Merge some BS1.7 changes:

internal_solid_infill_pattern

src/CMakeLists.txt

@@ -16,6 +16,7 @@ add_subdirectory(Shiny)
 add_subdirectory(semver)
 add_subdirectory(libigl)
 add_subdirectory(hints)
+add_subdirectory(mcut)
 
 # Adding libnest2d project for bin packing...
 add_subdirectory(libnest2d)

src/libslic3r/AABBMesh.cpp

@@ -0,0 +1,322 @@
+#include "AABBMesh.hpp"
+#include <Execution/ExecutionTBB.hpp>
+
+#include <libslic3r/AABBTreeIndirect.hpp>
+#include <libslic3r/TriangleMesh.hpp>
+
+#include <numeric>
+
+#ifdef SLIC3R_HOLE_RAYCASTER
+#include <libslic3r/SLA/Hollowing.hpp>
+#endif
+
+namespace Slic3r {
+
+class AABBMesh::AABBImpl {
+private:
+    AABBTreeIndirect::Tree3f m_tree;
+    double                   m_triangle_ray_epsilon;
+
+public:
+    void init(const indexed_triangle_set &its, bool calculate_epsilon)
+    {
+        m_triangle_ray_epsilon = 0.000001;
+        if (calculate_epsilon) {
+            // Calculate epsilon from average triangle edge length.
+            double l = its_average_edge_length(its);
+            if (l > 0)
+                m_triangle_ray_epsilon = 0.000001 * l * l;
+        }
+        m_tree = AABBTreeIndirect::build_aabb_tree_over_indexed_triangle_set(
+            its.vertices, its.indices);
+    }
+
+    void intersect_ray(const indexed_triangle_set &its,
+                       const Vec3d &               s,
+                       const Vec3d &               dir,
+                       igl::Hit &                  hit)
+    {
+        AABBTreeIndirect::intersect_ray_first_hit(its.vertices, its.indices,
+                                                  m_tree, s, dir, hit, m_triangle_ray_epsilon);
+    }
+
+    void intersect_ray(const indexed_triangle_set &its,
+                       const Vec3d &               s,
+                       const Vec3d &               dir,
+                       std::vector<igl::Hit> &     hits)
+    {
+        AABBTreeIndirect::intersect_ray_all_hits(its.vertices, its.indices,
+                                                 m_tree, s, dir, hits, m_triangle_ray_epsilon);
+    }
+
+    double squared_distance(const indexed_triangle_set & its,
+                            const Vec3d &                point,
+                            int &                        i,
+                            Eigen::Matrix<double, 1, 3> &closest)
+    {
+        size_t idx_unsigned = 0;
+        Vec3d  closest_vec3d(closest);
+        double dist =
+            AABBTreeIndirect::squared_distance_to_indexed_triangle_set(
+                its.vertices, its.indices, m_tree, point, idx_unsigned,
+                closest_vec3d);
+        i       = int(idx_unsigned);
+        closest = closest_vec3d;
+        return dist;
+    }
+};
+
+template<class M> void AABBMesh::init(const M &mesh, bool calculate_epsilon)
+{
+    // Build the AABB accelaration tree
+    m_aabb->init(*m_tm, calculate_epsilon);
+}
+
+AABBMesh::AABBMesh(const indexed_triangle_set &tmesh, bool calculate_epsilon)
+    : m_tm(&tmesh)
+    , m_aabb(new AABBImpl())
+    , m_vfidx{tmesh}
+    , m_fnidx{its_face_neighbors(tmesh)}
+{
+    init(tmesh, calculate_epsilon);
+}
+
+AABBMesh::AABBMesh(const TriangleMesh &mesh, bool calculate_epsilon)
+    : m_tm(&mesh.its)
+    , m_aabb(new AABBImpl())
+    , m_vfidx{mesh.its}
+    , m_fnidx{its_face_neighbors(mesh.its)}
+{
+    init(mesh, calculate_epsilon);
+}
+
+AABBMesh::~AABBMesh() {}
+
+AABBMesh::AABBMesh(const AABBMesh &other)
+    : m_tm(other.m_tm)
+    , m_aabb(new AABBImpl(*other.m_aabb))
+    , m_vfidx{other.m_vfidx}
+    , m_fnidx{other.m_fnidx}
+{}
+
+AABBMesh &AABBMesh::operator=(const AABBMesh &other)
+{
+    m_tm = other.m_tm;
+    m_aabb.reset(new AABBImpl(*other.m_aabb));
+    m_vfidx = other.m_vfidx;
+    m_fnidx = other.m_fnidx;
+
+    return *this;
+}
+
+AABBMesh &AABBMesh::operator=(AABBMesh &&other) = default;
+
+AABBMesh::AABBMesh(AABBMesh &&other) = default;
+
+
+
+const std::vector<Vec3f>& AABBMesh::vertices() const
+{
+    return m_tm->vertices;
+}
+
+
+
+const std::vector<Vec3i>& AABBMesh::indices()  const
+{
+    return m_tm->indices;
+}
+
+
+
+const Vec3f& AABBMesh::vertices(size_t idx) const
+{
+    return m_tm->vertices[idx];
+}
+
+
+
+const Vec3i& AABBMesh::indices(size_t idx) const
+{
+    return m_tm->indices[idx];
+}
+
+
+Vec3d AABBMesh::normal_by_face_id(int face_id) const {
+
+    return its_unnormalized_normal(*m_tm, face_id).cast<double>().normalized();
+}
+
+
+AABBMesh::hit_result
+AABBMesh::query_ray_hit(const Vec3d &s, const Vec3d &dir) const
+{
+    assert(is_approx(dir.norm(), 1.));
+    igl::Hit hit{-1, -1, 0.f, 0.f, 0.f};
+    hit.t = std::numeric_limits<float>::infinity();
+
+#ifdef SLIC3R_HOLE_RAYCASTER
+    if (! m_holes.empty()) {
+
+        // If there are holes, the hit_results will be made by
+        // query_ray_hits (object) and filter_hits (holes):
+        return filter_hits(query_ray_hits(s, dir));
+    }
+#endif
+
+    m_aabb->intersect_ray(*m_tm, s, dir, hit);
+    hit_result ret(*this);
+    ret.m_t = double(hit.t);
+    ret.m_dir = dir;
+    ret.m_source = s;
+    if(!std::isinf(hit.t) && !std::isnan(hit.t)) {
+        ret.m_normal = this->normal_by_face_id(hit.id);
+        ret.m_face_id = hit.id;
+    }
+
+    return ret;
+}
+
+std::vector<AABBMesh::hit_result>
+AABBMesh::query_ray_hits(const Vec3d &s, const Vec3d &dir) const
+{
+    std::vector<AABBMesh::hit_result> outs;
+    std::vector<igl::Hit> hits;
+    m_aabb->intersect_ray(*m_tm, s, dir, hits);
+
+    // The sort is necessary, the hits are not always sorted.
+    std::sort(hits.begin(), hits.end(),
+              [](const igl::Hit& a, const igl::Hit& b) { return a.t < b.t; });
+
+    // Remove duplicates. They sometimes appear, for example when the ray is cast
+    // along an axis of a cube due to floating-point approximations in igl (?)
+    hits.erase(std::unique(hits.begin(), hits.end(),
+                           [](const igl::Hit& a, const igl::Hit& b)
+                           { return a.t == b.t; }),
+               hits.end());
+
+    //  Convert the igl::Hit into hit_result
+    outs.reserve(hits.size());
+    for (const igl::Hit& hit : hits) {
+        outs.emplace_back(AABBMesh::hit_result(*this));
+        outs.back().m_t = double(hit.t);
+        outs.back().m_dir = dir;
+        outs.back().m_source = s;
+        if(!std::isinf(hit.t) && !std::isnan(hit.t)) {
+            outs.back().m_normal = this->normal_by_face_id(hit.id);
+            outs.back().m_face_id = hit.id;
+        }
+    }
+
+    return outs;
+}
+
+
+#ifdef SLIC3R_HOLE_RAYCASTER
+AABBMesh::hit_result IndexedMesh::filter_hits(
+    const std::vector<AABBMesh::hit_result>& object_hits) const
+{
+    assert(! m_holes.empty());
+    hit_result out(*this);
+
+    if (object_hits.empty())
+        return out;
+
+    const Vec3d& s = object_hits.front().source();
+    const Vec3d& dir = object_hits.front().direction();
+
+    // A helper struct to save an intersetion with a hole
+    struct HoleHit {
+        HoleHit(float t_p, const Vec3d& normal_p, bool entry_p) :
+            t(t_p), normal(normal_p), entry(entry_p) {}
+        float t;
+        Vec3d normal;
+        bool entry;
+    };
+    std::vector<HoleHit> hole_isects;
+    hole_isects.reserve(m_holes.size());
+
+    auto sf = s.cast<float>();
+    auto dirf = dir.cast<float>();
+
+    // Collect hits on all holes, preserve information about entry/exit
+    for (const sla::DrainHole& hole : m_holes) {
+        std::array<std::pair<float, Vec3d>, 2> isects;
+        if (hole.get_intersections(sf, dirf, isects)) {
+            // Ignore hole hits behind the source
+            if (isects[0].first > 0.f) hole_isects.emplace_back(isects[0].first, isects[0].second, true);
+            if (isects[1].first > 0.f) hole_isects.emplace_back(isects[1].first, isects[1].second, false);
+        }
+    }
+
+    // Holes can intersect each other, sort the hits by t
+    std::sort(hole_isects.begin(), hole_isects.end(),
+              [](const HoleHit& a, const HoleHit& b) { return a.t < b.t; });
+
+    // Now inspect the intersections with object and holes, in the order of
+    // increasing distance. Keep track how deep are we nested in mesh/holes and
+    // pick the correct intersection.
+    // This needs to be done twice - first to find out how deep in the structure
+    // the source is, then to pick the correct intersection.
+    int hole_nested = 0;
+    int object_nested = 0;
+    for (int dry_run=1; dry_run>=0; --dry_run) {
+        hole_nested = -hole_nested;
+        object_nested = -object_nested;
+
+        bool is_hole = false;
+        bool is_entry = false;
+        const HoleHit* next_hole_hit = hole_isects.empty() ? nullptr : &hole_isects.front();
+        const hit_result* next_mesh_hit = &object_hits.front();
+
+        while (next_hole_hit || next_mesh_hit) {
+            if (next_hole_hit && next_mesh_hit) // still have hole and obj hits
+                is_hole = (next_hole_hit->t < next_mesh_hit->m_t);
+            else
+                is_hole = next_hole_hit; // one or the other ran out
+
+            // Is this entry or exit hit?
+            is_entry = is_hole ? next_hole_hit->entry : ! next_mesh_hit->is_inside();
+
+            if (! dry_run) {
+                if (! is_hole && hole_nested == 0) {
+                    // This is a valid object hit
+                    return *next_mesh_hit;
+                }
+                if (is_hole && ! is_entry && object_nested != 0) {
+                    // This holehit is the one we seek
+                    out.m_t = next_hole_hit->t;
+                    out.m_normal = next_hole_hit->normal;
+                    out.m_source = s;
+                    out.m_dir = dir;
+                    return out;
+                }
+            }
+
+            // Increase/decrease the counter
+            (is_hole ? hole_nested : object_nested) += (is_entry ? 1 : -1);
+
+            // Advance the respective pointer
+            if (is_hole && next_hole_hit++ == &hole_isects.back())
+                next_hole_hit = nullptr;
+            if (! is_hole && next_mesh_hit++ == &object_hits.back())
+                next_mesh_hit = nullptr;
+        }
+    }
+
+    // if we got here, the ray ended up in infinity
+    return out;
+}
+#endif
+
+
+double AABBMesh::squared_distance(const Vec3d &p, int& i, Vec3d& c) const {
+    double sqdst = 0;
+    Eigen::Matrix<double, 1, 3> pp = p;
+    Eigen::Matrix<double, 1, 3> cc;
+    sqdst = m_aabb->squared_distance(*m_tm, pp, i, cc);
+    c = cc;
+    return sqdst;
+}
+
+} // namespace Slic3r

src/libslic3r/AABBMesh.hpp

@@ -0,0 +1,142 @@
+#ifndef PRUSASLICER_AABBMESH_H
+#define PRUSASLICER_AABBMESH_H
+
+#include <memory>
+#include <vector>
+
+#include <libslic3r/Point.hpp>
+#include <libslic3r/TriangleMesh.hpp>
+
+// There is an implementation of a hole-aware raycaster that was eventually
+// not used in production version. It is now hidden under following define
+// for possible future use.
+// #define SLIC3R_HOLE_RAYCASTER
+
+#ifdef SLIC3R_HOLE_RAYCASTER
+  #include "libslic3r/SLA/Hollowing.hpp"
+#endif
+
+struct indexed_triangle_set;
+
+namespace Slic3r {
+
+class TriangleMesh;
+
+// An index-triangle structure coupled with an AABB index to support ray
+// casting and other higher level operations.
+class AABBMesh {
+    class AABBImpl;
+
+    const indexed_triangle_set* m_tm;
+
+    std::unique_ptr<AABBImpl> m_aabb;
+    VertexFaceIndex m_vfidx;    // vertex-face index
+    std::vector<Vec3i> m_fnidx; // face-neighbor index
+
+#ifdef SLIC3R_HOLE_RAYCASTER
+    // This holds a copy of holes in the mesh. Initialized externally
+    // by load_mesh setter.
+    std::vector<sla::DrainHole> m_holes;
+#endif
+
+    template<class M> void init(const M &mesh, bool calculate_epsilon);
+
+public:
+
+    // calculate_epsilon ... calculate epsilon for triangle-ray intersection from an average triangle edge length.
+    // If set to false, a default epsilon is used, which works for "reasonable" meshes.
+    explicit AABBMesh(const indexed_triangle_set &tmesh, bool calculate_epsilon = false);
+    explicit AABBMesh(const TriangleMesh &mesh, bool calculate_epsilon = false);
+    
+    AABBMesh(const AABBMesh& other);
+    AABBMesh& operator=(const AABBMesh&);
+
+    AABBMesh(AABBMesh &&other);
+    AABBMesh& operator=(AABBMesh &&other);
+
+    ~AABBMesh();
+
+    const std::vector<Vec3f>& vertices() const;
+    const std::vector<Vec3i>& indices()  const;
+    const Vec3f& vertices(size_t idx) const;
+    const Vec3i& indices(size_t idx) const;
+
+    // Result of a raycast
+    class hit_result {
+        // m_t holds a distance from m_source to the intersection.
+        double m_t = infty();
+        int m_face_id = -1;
+        const AABBMesh *m_mesh = nullptr;
+        Vec3d m_dir    = Vec3d::Zero();
+        Vec3d m_source = Vec3d::Zero();
+        Vec3d m_normal = Vec3d::Zero();
+        friend class AABBMesh;
+        
+        // A valid object of this class can only be obtained from
+        // IndexedMesh::query_ray_hit method.
+        explicit inline hit_result(const AABBMesh& em): m_mesh(&em) {}
+    public:
+        // This denotes no hit on the mesh.
+        static inline constexpr double infty() { return std::numeric_limits<double>::infinity(); }
+        
+        explicit inline hit_result(double val = infty()) : m_t(val) {}
+        
+        inline double distance() const { return m_t; }
+        inline const Vec3d& direction() const { return m_dir; }
+        inline const Vec3d& source() const { return m_source; }
+        inline Vec3d position() const { return m_source + m_dir * m_t; }
+        inline int face() const { return m_face_id; }
+        inline bool is_valid() const { return m_mesh != nullptr; }
+        inline bool is_hit() const { return m_face_id >= 0 && !std::isinf(m_t); }
+
+        inline const Vec3d& normal() const {
+            assert(is_valid());
+            return m_normal;
+        }
+
+        inline bool is_inside() const {
+            return is_hit() && normal().dot(m_dir) > 0;
+        }
+    };
+
+#ifdef SLIC3R_HOLE_RAYCASTER
+    // Inform the object about location of holes
+    // creates internal copy of the vector
+    void load_holes(const std::vector<sla::DrainHole>& holes) {
+        m_holes = holes;
+    }
+
+    // Iterates over hits and holes and returns the true hit, possibly
+    // on the inside of a hole.
+    // This function is currently not used anywhere, it was written when the
+    // holes were subtracted on slices, that is, before we started using CGAL
+    // to actually cut the holes into the mesh.
+    hit_result filter_hits(const std::vector<AABBMesh::hit_result>& obj_hits) const;
+#endif
+
+    // Casting a ray on the mesh, returns the distance where the hit occures.
+    hit_result query_ray_hit(const Vec3d &s, const Vec3d &dir) const;
+    
+    // Casts a ray on the mesh and returns all hits
+    std::vector<hit_result> query_ray_hits(const Vec3d &s, const Vec3d &dir) const;
+
+    double squared_distance(const Vec3d& p, int& i, Vec3d& c) const;
+    inline double squared_distance(const Vec3d &p) const
+    {
+        int   i;
+        Vec3d c;
+        return squared_distance(p, i, c);
+    }
+
+    Vec3d normal_by_face_id(int face_id) const;
+
+    const indexed_triangle_set * get_triangle_mesh() const { return m_tm; }
+
+    const VertexFaceIndex &vertex_face_index() const { return m_vfidx; }
+    const std::vector<Vec3i> &face_neighbor_index() const { return m_fnidx; }
+};
+
+
+} // namespace Slic3r::sla
+
+#endif // INDEXEDMESH_H

src/libslic3r/AnyPtr.hpp

@@ -0,0 +1,130 @@
+#ifndef ANYPTR_HPP
+#define ANYPTR_HPP
+
+#include <memory>
+#include <type_traits>
+#include <boost/variant.hpp>
+
+namespace Slic3r {
+
+// A general purpose pointer holder that can hold any type of smart pointer
+// or raw pointer which can own or not own any object they point to.
+// In case a raw pointer is stored, it is not destructed so ownership is
+// assumed to be foreign.
+//
+// The stored pointer is not checked for being null when dereferenced.
+//
+// This is a movable only object due to the fact that it can possibly hold
+// a unique_ptr which a non-copy.
+template<class T>
+class AnyPtr {
+    enum { RawPtr, UPtr, ShPtr, WkPtr };
+
+    boost::variant<T*, std::unique_ptr<T>, std::shared_ptr<T>, std::weak_ptr<T>> ptr;
+
+    template<class Self> static T *get_ptr(Self &&s)
+    {
+        switch (s.ptr.which()) {
+        case RawPtr: return boost::get<T *>(s.ptr);
+        case UPtr: return boost::get<std::unique_ptr<T>>(s.ptr).get();
+        case ShPtr: return boost::get<std::shared_ptr<T>>(s.ptr).get();
+        case WkPtr: {
+            auto shptr = boost::get<std::weak_ptr<T>>(s.ptr).lock();
+            return shptr.get();
+        }
+        }
+
+        return nullptr;
+    }
+
+public:
+    template<class TT = T, class = std::enable_if_t<std::is_convertible_v<TT, T>>>
+    AnyPtr(TT *p = nullptr) : ptr{p}
+    {}
+    template<class TT, class = std::enable_if_t<std::is_convertible_v<TT, T>>>
+    AnyPtr(std::unique_ptr<TT> p) : ptr{std::unique_ptr<T>(std::move(p))}
+    {}
+    template<class TT, class = std::enable_if_t<std::is_convertible_v<TT, T>>>
+    AnyPtr(std::shared_ptr<TT> p) : ptr{std::shared_ptr<T>(std::move(p))}
+    {}
+    template<class TT, class = std::enable_if_t<std::is_convertible_v<TT, T>>>
+    AnyPtr(std::weak_ptr<TT> p) : ptr{std::weak_ptr<T>(std::move(p))}
+    {}
+
+    ~AnyPtr() = default;
+
+    AnyPtr(AnyPtr &&other) noexcept : ptr{std::move(other.ptr)} {}
+    AnyPtr(const AnyPtr &other) = delete;
+
+    AnyPtr &operator=(AnyPtr &&other) noexcept { ptr = std::move(other.ptr); return *this; }
+    AnyPtr &operator=(const AnyPtr &other) = delete;
+
+    template<class TT, class = std::enable_if_t<std::is_convertible_v<TT, T>>>
+    AnyPtr &operator=(TT *p) { ptr = p; return *this; }
+
+    template<class TT, class = std::enable_if_t<std::is_convertible_v<TT, T>>>
+    AnyPtr &operator=(std::unique_ptr<TT> p) { ptr = std::move(p); return *this; }
+
+    template<class TT, class = std::enable_if_t<std::is_convertible_v<TT, T>>>
+    AnyPtr &operator=(std::shared_ptr<TT> p) { ptr = p; return *this; }
+
+    template<class TT, class = std::enable_if_t<std::is_convertible_v<TT, T>>>
+    AnyPtr &operator=(std::weak_ptr<TT> p) { ptr = std::move(p); return *this; }
+
+    const T &operator*() const { return *get_ptr(*this); }
+    T &operator*() { return *get_ptr(*this); }
+
+    T *operator->() { return get_ptr(*this); }
+    const T *operator->() const { return get_ptr(*this); }
+
+    T *get() { return get_ptr(*this); }
+    const T *get() const { return get_ptr(*this); }
+
+    operator bool() const
+    {
+        switch (ptr.which()) {
+        case RawPtr: return bool(boost::get<T *>(ptr));
+        case UPtr: return bool(boost::get<std::unique_ptr<T>>(ptr));
+        case ShPtr: return bool(boost::get<std::shared_ptr<T>>(ptr));
+        case WkPtr: {
+            auto shptr = boost::get<std::weak_ptr<T>>(ptr).lock();
+            return bool(shptr);
+        }
+        }
+
+        return false;
+    }
+
+    // If the stored pointer is a shared or weak pointer, returns a reference
+    // counted copy. Empty shared pointer is returned otherwise.
+    std::shared_ptr<T> get_shared_cpy() const
+    {
+        std::shared_ptr<T> ret;
+
+        switch (ptr.which()) {
+        case ShPtr: ret = boost::get<std::shared_ptr<T>>(ptr); break;
+        case WkPtr: ret = boost::get<std::weak_ptr<T>>(ptr).lock(); break;
+        default:
+            ;
+        }
+
+        return ret;
+    }
+
+    // If the underlying pointer is unique, convert to shared pointer
+    void convert_unique_to_shared()
+    {
+        if (ptr.which() == UPtr)
+            ptr = std::shared_ptr<T>{std::move(boost::get<std::unique_ptr<T>>(ptr))};
+    }
+
+    // Returns true if the data is owned by this AnyPtr instance
+    bool is_owned() const noexcept
+    {
+        return ptr.which() == UPtr || ptr.which() == ShPtr;
+    }
+};
+
+} // namespace Slic3r
+
+#endif // ANYPTR_HPP

src/libslic3r/AppConfig.cpp

@@ -207,11 +207,17 @@ void AppConfig::set_defaults()
     if (get("developer_mode").empty())
         set_bool("developer_mode", false);
 
+    if (get("enable_ssl_for_mqtt").empty())
+        set_bool("enable_ssl_for_mqtt", true);
+
+    if (get("enable_ssl_for_ftp").empty())
+        set_bool("enable_ssl_for_ftp", true);
+
     if (get("severity_level").empty())
         set("severity_level", "info");
 
-    if (get("dump_video").empty())
+    if (get("internal_developer_mode").empty())
-        set_bool("dump_video", false);
+        set_bool("internal_developer_mode", false);
 
     // BBS
     if (get("preset_folder").empty())
@@ -571,14 +577,8 @@ std::string AppConfig::load()
 
 void AppConfig::save()
 {
-    {
+    if (! is_main_thread_active())
-        // Returns "undefined" if the thread naming functionality is not supported by the operating system.
+        throw CriticalException("Calling AppConfig::save() from a worker thread!");
-        std::optional<std::string> current_thread_name = get_current_thread_name();
-        if (current_thread_name && *current_thread_name != "bambustu_main" && *current_thread_name != "main") {
-            BOOST_LOG_TRIVIAL(error) << __FUNCTION__<<", current_thread_name is " << *current_thread_name;
-            throw CriticalException("Calling AppConfig::save() from a worker thread, thread name: " + *current_thread_name);
-        }
-    }
 
     // The config is first written to a file with a PID suffix and then moved
     // to avoid race conditions with multiple instances of Slic3r
@@ -838,12 +838,8 @@ std::string AppConfig::load()
 
 void AppConfig::save()
 {
-    {
+    if (! is_main_thread_active())
-        // Returns "undefined" if the thread naming functionality is not supported by the operating system.
+        throw CriticalException("Calling AppConfig::save() from a worker thread!");
-        std::optional<std::string> current_thread_name = get_current_thread_name();
-        if (current_thread_name && *current_thread_name != "bambustu_main")
-            throw CriticalException("Calling AppConfig::save() from a worker thread!");
-    }
 
     // The config is first written to a file with a PID suffix and then moved
     // to avoid race conditions with multiple instances of Slic3r

src/libslic3r/Brim.cpp

@@ -26,25 +26,29 @@ namespace Slic3r {
 static void append_and_translate(ExPolygons &dst, const ExPolygons &src, const PrintInstance &instance) {
     size_t dst_idx = dst.size();
     expolygons_append(dst, src);
+
+    Point instance_shift = instance.shift_without_plate_offset();
     for (; dst_idx < dst.size(); ++dst_idx)
-        dst[dst_idx].translate(instance.shift.x(), instance.shift.y());
+        dst[dst_idx].translate(instance_shift);
 }
 // BBS: generate brim area by objs
 static void append_and_translate(ExPolygons& dst, const ExPolygons& src,
     const PrintInstance& instance, const Print& print, std::map<ObjectID, ExPolygons>& brimAreaMap) {
     ExPolygons srcShifted = src;
-    for (size_t src_idx = 0; src_idx < src.size(); ++src_idx)
+    Point instance_shift = instance.shift_without_plate_offset();
-        srcShifted[src_idx].translate(instance.shift.x(), instance.shift.y());
+    for (size_t src_idx = 0; src_idx < srcShifted.size(); ++src_idx)
-    srcShifted = diff_ex(std::move(srcShifted), dst);
+        srcShifted[src_idx].translate(instance_shift);
+    srcShifted = diff_ex(srcShifted, dst);
     //expolygons_append(dst, temp2);
-    expolygons_append(brimAreaMap[instance.print_object->id()], srcShifted);
+    expolygons_append(brimAreaMap[instance.print_object->id()], std::move(srcShifted));
 }
 
 static void append_and_translate(Polygons &dst, const Polygons &src, const PrintInstance &instance) {
     size_t dst_idx = dst.size();
     polygons_append(dst, src);
+    Point instance_shift = instance.shift_without_plate_offset();
     for (; dst_idx < dst.size(); ++dst_idx)
-        dst[dst_idx].translate(instance.shift.x(), instance.shift.y());
+        dst[dst_idx].translate(instance_shift);
 }
 
 static float max_brim_width(const ConstPrintObjectPtrsAdaptor &objects)
@@ -89,12 +93,14 @@ static ConstPrintObjectPtrs get_top_level_objects_with_brim(const Print &print,
             islands_object.emplace_back(ex_poly.contour);
 
         islands.reserve(islands.size() + object->instances().size() * islands_object.size());
-        for (const PrintInstance &instance : object->instances())
+        for (const PrintInstance& instance : object->instances()) {
-            for (Polygon &poly : islands_object) {
+            Point instance_shift = instance.shift_without_plate_offset();
+            for (Polygon& poly : islands_object) {
                 islands.emplace_back(poly);
-                islands.back().translate(instance.shift);
+                islands.back().translate(instance_shift);
                 island_to_object.emplace_back(object);
             }
+        }
     }
     assert(islands.size() == island_to_object.size());
 
@@ -982,8 +988,6 @@ static ExPolygons outer_inner_brim_area(const Print& print,
         }
     }
     if (!bedExPoly.empty()){
-        auto plateOffset = print.get_plate_origin();
-        bedExPoly.front().translate(scale_(plateOffset.x()), scale_(plateOffset.y()));
         no_brim_area.push_back(bedExPoly.front());
     }
     for (const PrintObject* object : print.objects()) {
@@ -1224,8 +1228,9 @@ static void make_inner_island_brim(const Print& print, const ConstPrintObjectPtr
                 for (const PrintInstance& instance : object->instances()) {
                     size_t dst_idx = final_loops.size();
                     final_loops.insert(final_loops.end(), all_loops_object.begin(), all_loops_object.end());
+                    Point instance_shift = instance.shift_without_plate_offset();
                     for (; dst_idx < final_loops.size(); ++dst_idx)
-                        final_loops[dst_idx].translate(instance.shift.x(), instance.shift.y());
+                        final_loops[dst_idx].translate(instance_shift);
 
                 }
                 extrusion_entities_append_loops_and_paths(brim.entities, std::move(final_loops),
@@ -1561,6 +1566,12 @@ ExtrusionEntityCollection makeBrimInfill(const ExPolygons& singleBrimArea, const
     optimize_polylines_by_reversing(&all_loops);
     all_loops = connect_brim_lines(std::move(all_loops), offset(singleBrimArea, float(SCALED_EPSILON)), float(flow.scaled_spacing()) * 2.f);
 
+    //BBS: finally apply the plate offset which may very large
+    auto plate_offset = print.get_plate_origin();
+    Point scaled_plate_offset = Point(scaled(plate_offset.x()), scaled(plate_offset.y()));
+    for (Polyline& one_loop : all_loops)
+        one_loop.translate(scaled_plate_offset);
+
     extrusion_entities_append_loops_and_paths(brim.entities, std::move(all_loops), erBrim, float(flow.mm3_per_mm()), float(flow.width()), float(print.skirt_first_layer_height()));
     return brim;
 }
@@ -1589,14 +1600,14 @@ void make_brim(const Print& print, PrintTryCancel try_cancel, Polygons& islands_
         for (const ExPolygon& ex_poly : object->layers().front()->lslices)
             for (const PrintInstance& instance : object->instances()) {
                 auto ex_poly_translated = ex_poly;
-                ex_poly_translated.translate(instance.shift.x(), instance.shift.y());
+                ex_poly_translated.translate(instance.shift_without_plate_offset());
                 bbx.merge(get_extents(ex_poly_translated.contour));
             }
         if (!object->support_layers().empty())
         for (const Polygon& support_contour : object->support_layers().front()->support_fills.polygons_covered_by_spacing())
             for (const PrintInstance& instance : object->instances()) {
                 auto ex_poly_translated = support_contour;
-                ex_poly_translated.translate(instance.shift.x(), instance.shift.y());
+                ex_poly_translated.translate(instance.shift_without_plate_offset());
                 bbx.merge(get_extents(ex_poly_translated));
             }
         if (supportBrimAreaMap.find(printObjID) != supportBrimAreaMap.end()) {
@@ -1611,6 +1622,13 @@ void make_brim(const Print& print, PrintTryCancel try_cancel, Polygons& islands_
     }
 
     islands_area = to_polygons(islands_area_ex);
+
+    // BBS: plate offset is applied
+    const Vec3d plate_offset = print.get_plate_origin();
+    Point plate_shift = Point(scaled(plate_offset.x()), scaled(plate_offset.y()));
+    for (size_t iia = 0; iia < islands_area.size(); ++iia)
+        islands_area[iia].translate(plate_shift);
+
     for (auto iter = brimAreaMap.begin(); iter != brimAreaMap.end(); ++iter) {
         if (!iter->second.empty()) {
             brimMap.insert(std::make_pair(iter->first, makeBrimInfill(iter->second, print, islands_area)));

src/libslic3r/CMakeLists.txt

@@ -24,6 +24,9 @@ set(lisbslic3r_sources
     pchheader.hpp
     AABBTreeIndirect.hpp
     AABBTreeLines.hpp
+    AABBMesh.hpp
+    AABBMesh.cpp
+    AnyPtr.hpp
     BoundingBox.cpp
     BoundingBox.hpp
     BridgeDetector.cpp
@@ -96,6 +99,8 @@ set(lisbslic3r_sources
     Fill/FillRectilinear.hpp
     Flow.cpp
     Flow.hpp
+    FlushVolCalc.cpp
+    FlushVolCalc.hpp
     format.hpp
     Format/3mf.cpp
     Format/3mf.hpp
@@ -430,7 +435,7 @@ if (_opts)
     target_compile_options(libslic3r_cgal PRIVATE "${_opts_bad}")
 endif()
 
-target_link_libraries(libslic3r_cgal PRIVATE ${_cgal_tgt} libigl)
+target_link_libraries(libslic3r_cgal PRIVATE ${_cgal_tgt} libigl mcut)
 
 if (MSVC AND "${CMAKE_SIZEOF_VOID_P}" STREQUAL "4") # 32 bit MSVC workaround
     target_compile_definitions(libslic3r_cgal PRIVATE CGAL_DO_NOT_USE_MPZF)
@@ -497,6 +502,7 @@ target_link_libraries(libslic3r
     ZLIB::ZLIB
     ${OCCT_LIBS}
     Clipper2
+    mcut
     )
 
 if(NOT WIN32)

src/libslic3r/CSGMesh/CSGMesh.hpp

@@ -0,0 +1,86 @@
+#ifndef CSGMESH_HPP
+#define CSGMESH_HPP
+
+#include <libslic3r/AnyPtr.hpp>
+#include <admesh/stl.h>
+
+namespace Slic3r { namespace csg {
+
+// A CSGPartT should be an object that can provide at least a mesh + trafo and an
+// associated csg operation. A collection of CSGPartT objects can then
+// be interpreted as one model and used in various contexts. It can be assembled
+// with CGAL or OpenVDB, rendered with OpenCSG or provided to a ray-tracer to
+// deal with various parts of it according to the supported CSG types...
+//
+// A few simple templated interface functions are provided here and a default
+// CSGPart class that implements the necessary means to be usable as a
+// CSGPartT object.
+
+// Supported CSG operation types
+enum class CSGType { Union, Difference, Intersection };
+
+// A CSG part can instruct the processing to push the sub-result until a new
+// csg part with a pop instruction appears. This can be used to implement
+// parentheses in a CSG expression represented by the collection of csg parts.
+// A CSG part can not contain another CSG collection, only a mesh, this is why
+// its easier to do this stacking instead of recursion in the data definition.
+// CSGStackOp::Continue means no stack operation required.
+// When a CSG part contains a Push instruction, it is expected that the CSG
+// operation it contains refers to the whole collection spanning to the nearest
+// part with a Pop instruction.
+// e.g.:
+// {
+//      CUBE1: { mesh: cube, op: Union, stack op: Continue },
+//      CUBE2: { mesh: cube, op: Difference, stack op: Push},
+//      CUBE3: { mesh: cube, op: Union, stack op: Pop}
+// }
+// is a collection of csg parts representing the expression CUBE1 - (CUBE2 + CUBE3)
+enum class CSGStackOp { Push, Continue, Pop };
+
+// Get the CSG operation of the part. Can be overriden for any type
+template<class CSGPartT> CSGType get_operation(const CSGPartT &part)
+{
+    return part.operation;
+}
+
+// Get the stack operation required by the CSG part.
+template<class CSGPartT> CSGStackOp get_stack_operation(const CSGPartT &part)
+{
+    return part.stack_operation;
+}
+
+// Get the mesh for the part. Can be overriden for any type
+template<class CSGPartT>
+const indexed_triangle_set *get_mesh(const CSGPartT &part)
+{
+    return part.its_ptr.get();
+}
+
+// Get the transformation associated with the mesh inside a CSGPartT object.
+// Can be overriden for any type.
+template<class CSGPartT>
+Transform3f get_transform(const CSGPartT &part)
+{
+    return part.trafo;
+}
+
+// Default implementation
+struct CSGPart {
+    AnyPtr<const indexed_triangle_set> its_ptr;
+    Transform3f trafo;
+    CSGType operation;
+    CSGStackOp stack_operation;
+
+    CSGPart(AnyPtr<const indexed_triangle_set> ptr = {},
+            CSGType                            op  = CSGType::Union,
+            const Transform3f                 &tr  = Transform3f::Identity())
+        : its_ptr{std::move(ptr)}
+        , operation{op}
+        , stack_operation{CSGStackOp::Continue}
+        , trafo{tr}
+    {}
+};
+
+}} // namespace Slic3r::csg
+
+#endif // CSGMESH_HPP

src/libslic3r/CSGMesh/CSGMeshCopy.hpp

@@ -0,0 +1,80 @@
+#ifndef CSGMESHCOPY_HPP
+#define CSGMESHCOPY_HPP
+
+#include "CSGMesh.hpp"
+
+namespace Slic3r { namespace csg {
+
+// Copy a csg range but for the meshes, only copy the pointers. If the copy
+// is made from a CSGPart compatible object, and the pointer is a shared one,
+// it will be copied with reference counting.
+template<class It, class OutIt>
+void copy_csgrange_shallow(const Range<It> &csgrange, OutIt out)
+{
+    for (const auto &part : csgrange) {
+        CSGPart cpy{{},
+                    get_operation(part),
+                    get_transform(part)};
+
+        cpy.stack_operation = get_stack_operation(part);
+
+        if constexpr (std::is_convertible_v<decltype(part), const CSGPart&>) {
+            if (auto shptr = part.its_ptr.get_shared_cpy()) {
+                cpy.its_ptr = shptr;
+            }
+        }
+
+        if (!cpy.its_ptr)
+            cpy.its_ptr = AnyPtr<const indexed_triangle_set>{get_mesh(part)};
+
+        *out = std::move(cpy);
+        ++out;
+    }
+}
+
+// Copy the csg range, allocating new meshes
+template<class It, class OutIt>
+void copy_csgrange_deep(const Range<It> &csgrange, OutIt out)
+{
+    for (const auto &part : csgrange) {
+
+        CSGPart cpy{{}, get_operation(part), get_transform(part)};
+
+        if (auto meshptr = get_mesh(part)) {
+            cpy.its_ptr = std::make_unique<const indexed_triangle_set>(*meshptr);
+        }
+
+        cpy.stack_operation = get_stack_operation(part);
+
+        *out = std::move(cpy);
+        ++out;
+    }
+}
+
+template<class ItA, class ItB>
+bool is_same(const Range<ItA> &A, const Range<ItB> &B)
+{
+    bool ret = true;
+
+    size_t s = A.size();
+
+    if (B.size() != s)
+        ret = false;
+
+    size_t i = 0;
+    auto itA = A.begin();
+    auto itB = B.begin();
+    for (; ret && i < s; ++itA, ++itB, ++i) {
+        ret = ret &&
+              get_mesh(*itA) == get_mesh(*itB) &&
+              get_operation(*itA) == get_operation(*itB) &&
+              get_stack_operation(*itA) == get_stack_operation(*itB) &&
+              get_transform(*itA).isApprox(get_transform(*itB));
+    }
+
+    return ret;
+}
+
+}} // namespace Slic3r::csg
+
+#endif // CSGCOPY_HPP

src/libslic3r/CSGMesh/ModelToCSGMesh.hpp

@@ -0,0 +1,92 @@
+#ifndef MODELTOCSGMESH_HPP
+#define MODELTOCSGMESH_HPP
+
+#include "CSGMesh.hpp"
+
+#include "libslic3r/Model.hpp"
+#include "libslic3r/SLA/Hollowing.hpp"
+#include "libslic3r/MeshSplitImpl.hpp"
+
+namespace Slic3r { namespace csg {
+
+// Flags to select which parts to export from Model into a csg part collection.
+// These flags can be chained with the | operator
+enum ModelParts {
+    mpartsPositive = 1,   // Include positive parts
+    mpartsNegative = 2,   // Include negative parts
+    mpartsDrillHoles = 4, // Include drill holes
+    mpartsDoSplits = 8,   // Split each splitable mesh and export as a union of csg parts
+};
+
+template<class OutIt>
+bool model_to_csgmesh(const ModelObject &mo,
+                      const Transform3d &trafo, // Applies to all exported parts
+                      OutIt              out,   // Output iterator
+                      // values of ModelParts OR-ed
+                      int                parts_to_include = mpartsPositive
+                      )
+{
+    bool do_positives  = parts_to_include & mpartsPositive;
+    bool do_negatives  = parts_to_include & mpartsNegative;
+    bool do_drillholes = parts_to_include & mpartsDrillHoles;
+    bool do_splits     = parts_to_include & mpartsDoSplits;
+    bool has_splitable_volume = false;
+
+    for (const ModelVolume *vol : mo.volumes) {
+        if (vol && vol->mesh_ptr() &&
+            ((do_positives && vol->is_model_part()) ||
+             (do_negatives && vol->is_negative_volume()))) {
+
+            if (do_splits && its_is_splittable(vol->mesh().its)) {
+                CSGPart part_begin{{}, vol->is_model_part() ? CSGType::Union : CSGType::Difference};
+                part_begin.stack_operation = CSGStackOp::Push;
+                *out = std::move(part_begin);
+                ++out;
+
+                its_split(vol->mesh().its, SplitOutputFn{[&out, &vol, &trafo](indexed_triangle_set &&its) {
+                              if (its.empty())
+                                  return;
+
+                              CSGPart part{std::make_unique<indexed_triangle_set>(std::move(its)),
+                                       CSGType::Union,
+                                       (trafo * vol->get_matrix()).cast<float>()};
+
+                              *out = std::move(part);
+                              ++out;
+                          }});
+
+                CSGPart part_end{{}};
+                part_end.stack_operation = CSGStackOp::Pop;
+                *out = std::move(part_end);
+                ++out;
+                has_splitable_volume = true;
+            } else {
+                CSGPart part{&(vol->mesh().its),
+                             vol->is_model_part() ? CSGType::Union : CSGType::Difference,
+                             (trafo * vol->get_matrix()).cast<float>()};
+
+                *out = std::move(part);
+                ++out;
+            }
+        }
+    }
+
+    //if (do_drillholes) {
+    //    sla::DrainHoles drainholes = sla::transformed_drainhole_points(mo, trafo);
+
+    //    for (const sla::DrainHole &dhole : drainholes) {
+    //        CSGPart part{std::make_unique<const indexed_triangle_set>(
+    //                         dhole.to_mesh()),
+    //                     CSGType::Difference};
+
+    //        *out = std::move(part);
+    //        ++out;
+    //    }
+    //}
+
+    return has_splitable_volume;
+}
+
+}} // namespace Slic3r::csg
+
+#endif // MODELTOCSGMESH_HPP

src/libslic3r/CSGMesh/PerformCSGMeshBooleans.hpp

@@ -0,0 +1,375 @@
+#ifndef PERFORMCSGMESHBOOLEANS_HPP
+#define PERFORMCSGMESHBOOLEANS_HPP
+
+#include <stack>
+#include <vector>
+
+#include "CSGMesh.hpp"
+
+#include "libslic3r/Execution/ExecutionTBB.hpp"
+//#include "libslic3r/Execution/ExecutionSeq.hpp"
+#include "libslic3r/MeshBoolean.hpp"
+
+namespace Slic3r { namespace csg {
+
+// This method can be overriden when a specific CSGPart type supports caching
+// of the voxel grid
+template<class CSGPartT>
+MeshBoolean::cgal::CGALMeshPtr get_cgalmesh(const CSGPartT &csgpart)
+{
+    const indexed_triangle_set *its = csg::get_mesh(csgpart);
+    indexed_triangle_set dummy;
+
+    if (!its)
+        its = &dummy;
+
+    MeshBoolean::cgal::CGALMeshPtr ret;
+
+    indexed_triangle_set m = *its;
+    its_transform(m, get_transform(csgpart), true);
+
+    try {
+        ret = MeshBoolean::cgal::triangle_mesh_to_cgal(m);
+    } catch (...) {
+        // errors are ignored, simply return null
+        ret = nullptr;
+    }
+
+    return ret;
+}
+
+// This method can be overriden when a specific CSGPart type supports caching
+// of the voxel grid
+template<class CSGPartT>
+MeshBoolean::mcut::McutMeshPtr get_mcutmesh(const CSGPartT& csgpart)
+{
+    const indexed_triangle_set* its = csg::get_mesh(csgpart);
+    indexed_triangle_set dummy;
+
+    if (!its)
+        its = &dummy;
+
+    MeshBoolean::mcut::McutMeshPtr ret;
+
+    indexed_triangle_set m = *its;
+    its_transform(m, get_transform(csgpart), true);
+
+    try {
+        ret = MeshBoolean::mcut::triangle_mesh_to_mcut(m);
+    }
+    catch (...) {
+        // errors are ignored, simply return null
+        ret = nullptr;
+    }
+
+    return ret;
+}
+
+namespace detail_cgal {
+
+using MeshBoolean::cgal::CGALMeshPtr;
+
+inline void perform_csg(CSGType op, CGALMeshPtr &dst, CGALMeshPtr &src)
+{
+    if (!dst && op == CSGType::Union && src) {
+        dst = std::move(src);
+        return;
+    }
+
+    if (!dst || !src)
+        return;
+
+    switch (op) {
+    case CSGType::Union:
+        MeshBoolean::cgal::plus(*dst, *src);
+        break;
+    case CSGType::Difference:
+        MeshBoolean::cgal::minus(*dst, *src);
+        break;
+    case CSGType::Intersection:
+        MeshBoolean::cgal::intersect(*dst, *src);
+        break;
+    }
+}
+
+template<class Ex, class It>
+std::vector<CGALMeshPtr> get_cgalptrs(Ex policy, const Range<It> &csgrange)
+{
+    std::vector<CGALMeshPtr> ret(csgrange.size());
+    execution::for_each(policy, size_t(0), csgrange.size(),
+                        [&csgrange, &ret](size_t i) {
+        auto it = csgrange.begin();
+        std::advance(it, i);
+        auto &csgpart = *it;
+        ret[i]        = get_cgalmesh(csgpart);
+    });
+
+    return ret;
+}
+
+} // namespace detail
+
+namespace detail_mcut {
+
+    using MeshBoolean::mcut::McutMeshPtr;
+
+    inline void perform_csg(CSGType op, McutMeshPtr& dst, McutMeshPtr& src)
+    {
+        if (!dst && op == CSGType::Union && src) {
+            dst = std::move(src);
+            return;
+        }
+
+        if (!dst || !src)
+            return;
+
+        switch (op) {
+        case CSGType::Union:
+            MeshBoolean::mcut::do_boolean(*dst, *src,"UNION");
+            break;
+        case CSGType::Difference:
+            MeshBoolean::mcut::do_boolean(*dst, *src,"A_NOT_B");
+            break;
+        case CSGType::Intersection:
+            MeshBoolean::mcut::do_boolean(*dst, *src,"INTERSECTION");
+            break;
+        }
+    }
+
+    template<class Ex, class It>
+    std::vector<McutMeshPtr> get_mcutptrs(Ex policy, const Range<It>& csgrange)
+    {
+        std::vector<McutMeshPtr> ret(csgrange.size());
+        execution::for_each(policy, size_t(0), csgrange.size(),
+            [&csgrange, &ret](size_t i) {
+                auto it = csgrange.begin();
+                std::advance(it, i);
+                auto& csgpart = *it;
+                ret[i] = get_mcutmesh(csgpart);
+            });
+
+        return ret;
+    }
+
+} // namespace mcut_detail
+
+// Process the sequence of CSG parts with CGAL.
+template<class It>
+void perform_csgmesh_booleans_cgal(MeshBoolean::cgal::CGALMeshPtr &cgalm,
+                              const Range<It>                &csgrange)
+{
+    using MeshBoolean::cgal::CGALMesh;
+    using MeshBoolean::cgal::CGALMeshPtr;
+    using namespace detail_cgal;
+
+    struct Frame {
+        CSGType op; CGALMeshPtr cgalptr;
+        explicit Frame(CSGType csgop = CSGType::Union)
+            : op{ csgop }
+            , cgalptr{ MeshBoolean::cgal::triangle_mesh_to_cgal(indexed_triangle_set{}) }
+        {}
+    };
+
+    std::stack opstack{ std::vector<Frame>{} };
+
+    opstack.push(Frame{});
+
+    std::vector<CGALMeshPtr> cgalmeshes = get_cgalptrs(ex_tbb, csgrange);
+
+    size_t csgidx = 0;
+    for (auto& csgpart : csgrange) {
+
+        auto op = get_operation(csgpart);
+        CGALMeshPtr& cgalptr = cgalmeshes[csgidx++];
+
+        if (get_stack_operation(csgpart) == CSGStackOp::Push) {
+            opstack.push(Frame{ op });
+            op = CSGType::Union;
+        }
+
+        Frame* top = &opstack.top();
+
+        perform_csg(get_operation(csgpart), top->cgalptr, cgalptr);
+
+        if (get_stack_operation(csgpart) == CSGStackOp::Pop) {
+            CGALMeshPtr src = std::move(top->cgalptr);
+            auto popop = opstack.top().op;
+            opstack.pop();
+            CGALMeshPtr& dst = opstack.top().cgalptr;
+            perform_csg(popop, dst, src);
+        }
+    }
+
+    cgalm = std::move(opstack.top().cgalptr);
+}
+
+// Process the sequence of CSG parts with mcut.
+template<class It>
+void perform_csgmesh_booleans_mcut(MeshBoolean::mcut::McutMeshPtr& mcutm,
+    const Range<It>& csgrange)
+{
+    using MeshBoolean::mcut::McutMesh;
+    using MeshBoolean::mcut::McutMeshPtr;
+    using namespace detail_mcut;
+
+    struct Frame {
+        CSGType op; McutMeshPtr mcutptr;
+        explicit Frame(CSGType csgop = CSGType::Union)
+            : op{ csgop }
+            , mcutptr{ MeshBoolean::mcut::triangle_mesh_to_mcut(indexed_triangle_set{}) }
+        {}
+    };
+
+    std::stack opstack{ std::vector<Frame>{} };
+
+    opstack.push(Frame{});
+
+    std::vector<McutMeshPtr> McutMeshes = get_mcutptrs(ex_tbb, csgrange);
+
+    size_t csgidx = 0;
+    for (auto& csgpart : csgrange) {
+
+        auto op = get_operation(csgpart);
+        McutMeshPtr& mcutptr = McutMeshes[csgidx++];
+
+        if (get_stack_operation(csgpart) == CSGStackOp::Push) {
+            opstack.push(Frame{ op });
+            op = CSGType::Union;
+        }
+
+        Frame* top = &opstack.top();
+
+        perform_csg(get_operation(csgpart), top->mcutptr, mcutptr);
+
+        if (get_stack_operation(csgpart) == CSGStackOp::Pop) {
+            McutMeshPtr src = std::move(top->mcutptr);
+            auto popop = opstack.top().op;
+            opstack.pop();
+            McutMeshPtr& dst = opstack.top().mcutptr;
+            perform_csg(popop, dst, src);
+        }
+    }
+
+    mcutm = std::move(opstack.top().mcutptr);
+    
+}
+
+
+template<class It, class Visitor>
+It check_csgmesh_booleans(const Range<It> &csgrange, Visitor &&vfn)
+{
+    using namespace detail_cgal;
+
+    std::vector<CGALMeshPtr> cgalmeshes(csgrange.size());
+    auto check_part = [&csgrange, &cgalmeshes](size_t i)
+    {
+        auto it = csgrange.begin();
+        std::advance(it, i);
+        auto &csgpart = *it;
+        auto m = get_cgalmesh(csgpart);
+
+        // mesh can be nullptr if this is a stack push or pull
+        if (!get_mesh(csgpart) && get_stack_operation(csgpart) != CSGStackOp::Continue) {
+            cgalmeshes[i] = MeshBoolean::cgal::triangle_mesh_to_cgal(indexed_triangle_set{});
+            return;
+        }
+
+        try {
+            if (!m || MeshBoolean::cgal::empty(*m))
+                return;
+
+            if (!MeshBoolean::cgal::does_bound_a_volume(*m))
+                return;
+
+            if (MeshBoolean::cgal::does_self_intersect(*m))
+                return;
+        }
+        catch (...) { return; }
+
+        cgalmeshes[i] = std::move(m);
+    };
+    execution::for_each(ex_tbb, size_t(0), csgrange.size(), check_part);
+
+    It ret = csgrange.end();
+    for (size_t i = 0; i < csgrange.size(); ++i) {
+        if (!cgalmeshes[i]) {
+            auto it = csgrange.begin();
+            std::advance(it, i);
+            vfn(it);
+
+            if (ret == csgrange.end())
+                ret = it;
+        }
+    }
+
+    return ret;
+}
+
+template<class It>
+It check_csgmesh_booleans(const Range<It> &csgrange, bool use_mcut=false)
+{
+    if(!use_mcut)
+        return check_csgmesh_booleans(csgrange, [](auto &) {});
+    else {
+        using namespace detail_mcut;
+
+        std::vector<McutMeshPtr> McutMeshes(csgrange.size());
+        auto check_part = [&csgrange, &McutMeshes](size_t i) {
+            auto it = csgrange.begin();
+            std::advance(it, i);
+            auto& csgpart = *it;
+            auto m = get_mcutmesh(csgpart);
+
+            // mesh can be nullptr if this is a stack push or pull
+            if (!get_mesh(csgpart) && get_stack_operation(csgpart) != CSGStackOp::Continue) {
+                McutMeshes[i] = MeshBoolean::mcut::triangle_mesh_to_mcut(indexed_triangle_set{});
+                return;
+            }
+
+            try {
+                if (!m || MeshBoolean::mcut::empty(*m))
+                    return;
+            }
+            catch (...) { return; }
+
+            McutMeshes[i] = std::move(m);
+        };
+        execution::for_each(ex_tbb, size_t(0), csgrange.size(), check_part);
+
+        It ret = csgrange.end();
+        for (size_t i = 0; i < csgrange.size(); ++i) {
+            if (!McutMeshes[i]) {
+                auto it = csgrange.begin();
+                std::advance(it, i);
+
+                if (ret == csgrange.end())
+                    ret = it;
+            }
+        }
+
+        return ret;
+    }
+}
+
+template<class It>
+MeshBoolean::cgal::CGALMeshPtr perform_csgmesh_booleans(const Range<It> &csgparts)
+{
+    auto ret = MeshBoolean::cgal::triangle_mesh_to_cgal(indexed_triangle_set{});
+    if (ret)
+        perform_csgmesh_booleans_cgal(ret, csgparts);
+    return ret;
+}
+
+template<class It>
+MeshBoolean::mcut::McutMeshPtr  perform_csgmesh_booleans_mcut(const Range<It>& csgparts)
+{
+    auto ret = MeshBoolean::mcut::triangle_mesh_to_mcut(indexed_triangle_set{});
+    if (ret)
+        perform_csgmesh_booleans_mcut(ret, csgparts);
+    return ret;
+}
+
+} // namespace csg
+} // namespace Slic3r
+
+#endif // PERFORMCSGMESHBOOLEANS_HPP

src/libslic3r/CSGMesh/SliceCSGMesh.hpp

@@ -0,0 +1,131 @@
+#ifndef SLICECSGMESH_HPP
+#define SLICECSGMESH_HPP
+
+#include "CSGMesh.hpp"
+
+#include <stack>
+
+#include "libslic3r/TriangleMeshSlicer.hpp"
+#include "libslic3r/ClipperUtils.hpp"
+#include "libslic3r/Execution/ExecutionTBB.hpp"
+
+namespace Slic3r { namespace csg {
+
+namespace detail {
+
+inline void merge_slices(csg::CSGType op, size_t i,
+                  std::vector<ExPolygons> &target,
+                  std::vector<ExPolygons> &source)
+{
+    switch(op) {
+    case CSGType::Union:
+        for (ExPolygon &expoly : source[i])
+            target[i].emplace_back(std::move(expoly));
+        break;
+    case CSGType::Difference:
+        target[i] = diff_ex(target[i], source[i]);
+        break;
+    case CSGType::Intersection:
+        target[i] = intersection_ex(target[i], source[i]);
+        break;
+    }
+}
+
+inline void collect_nonempty_indices(csg::CSGType                   op,
+                              const std::vector<float>      &slicegrid,
+                              const std::vector<ExPolygons> &slices,
+                              std::vector<size_t>           &indices)
+{
+    indices.clear();
+    for (size_t i = 0; i < slicegrid.size(); ++i) {
+        if (op == CSGType::Intersection || !slices[i].empty())
+            indices.emplace_back(i);
+    }
+}
+
+} // namespace detail
+
+template<class ItCSG>
+std::vector<ExPolygons> slice_csgmesh_ex(
+    const Range<ItCSG>          &csgrange,
+    const std::vector<float>    &slicegrid,
+    const MeshSlicingParamsEx   &params,
+    const std::function<void()> &throw_on_cancel = [] {})
+{
+    using namespace detail;
+
+    struct Frame { CSGType op; std::vector<ExPolygons> slices; };
+
+    std::stack opstack{std::vector<Frame>{}};
+
+    MeshSlicingParamsEx params_cpy = params;
+    auto trafo = params.trafo;
+    auto nonempty_indices = reserve_vector<size_t>(slicegrid.size());
+
+    opstack.push({CSGType::Union, std::vector<ExPolygons>(slicegrid.size())});
+
+    for (const auto &csgpart : csgrange) {
+        const indexed_triangle_set *its = csg::get_mesh(csgpart);
+
+        auto op = get_operation(csgpart);
+
+        if (get_stack_operation(csgpart) == CSGStackOp::Push) {
+            opstack.push({op, std::vector<ExPolygons>(slicegrid.size())});
+            op = CSGType::Union;
+        }
+
+        Frame *top = &opstack.top();
+
+        if (its) {
+            params_cpy.trafo = trafo * csg::get_transform(csgpart).template cast<double>();
+            std::vector<ExPolygons> slices = slice_mesh_ex(*its,
+                                                           slicegrid, params_cpy,
+                                                           throw_on_cancel);
+
+            assert(slices.size() == slicegrid.size());
+
+            collect_nonempty_indices(op, slicegrid, slices, nonempty_indices);
+
+            execution::for_each(
+                ex_tbb, nonempty_indices.begin(), nonempty_indices.end(),
+                [op, &slices, &top](size_t i) {
+                    merge_slices(op, i, top->slices, slices);
+                }, execution::max_concurrency(ex_tbb));
+        }
+
+        if (get_stack_operation(csgpart) == CSGStackOp::Pop) {
+            std::vector<ExPolygons> popslices = std::move(top->slices);
+            auto popop = opstack.top().op;
+            opstack.pop();
+            std::vector<ExPolygons> &prev_slices = opstack.top().slices;
+
+            collect_nonempty_indices(popop, slicegrid, popslices, nonempty_indices);
+
+            execution::for_each(
+                ex_tbb, nonempty_indices.begin(), nonempty_indices.end(),
+                [&popslices, &prev_slices, popop](size_t i) {
+                    merge_slices(popop, i, prev_slices, popslices);
+                }, execution::max_concurrency(ex_tbb));
+        }
+    }
+
+    std::vector<ExPolygons> ret = std::move(opstack.top().slices);
+
+    // TODO: verify if this part can be omitted or not.
+    execution::for_each(ex_tbb, ret.begin(), ret.end(), [](ExPolygons &slice) {
+        auto it = std::remove_if(slice.begin(), slice.end(), [](const ExPolygon &p){
+            return p.area() < double(SCALED_EPSILON) * double(SCALED_EPSILON);
+        });
+
+        // Hopefully, ExPolygons are moved, not copied to new positions
+        // and that is cheap for expolygons
+        slice.erase(it, slice.end());
+        slice = union_ex(slice);
+    }, execution::max_concurrency(ex_tbb));
+
+    return ret;
+}
+
+}} // namespace Slic3r::csg
+
+#endif // SLICECSGMESH_HPP

src/libslic3r/CSGMesh/TriangleMeshAdapter.hpp

@@ -0,0 +1,95 @@
+#ifndef TRIANGLEMESHADAPTER_HPP
+#define TRIANGLEMESHADAPTER_HPP
+
+#include "CSGMesh.hpp"
+
+#include "libslic3r/TriangleMesh.hpp"
+
+namespace Slic3r { namespace csg {
+
+// Provide default overloads for indexed_triangle_set to be usable as a plain
+// CSGPart with an implicit union operation
+
+inline CSGType get_operation(const indexed_triangle_set &part)
+{
+    return CSGType::Union;
+}
+
+inline CSGStackOp get_stack_operation(const indexed_triangle_set &part)
+{
+    return CSGStackOp::Continue;
+}
+
+inline const indexed_triangle_set * get_mesh(const indexed_triangle_set &part)
+{
+    return ∂
+}
+
+inline Transform3f get_transform(const indexed_triangle_set &part)
+{
+    return Transform3f::Identity();
+}
+
+inline CSGType get_operation(const indexed_triangle_set *const part)
+{
+    return CSGType::Union;
+}
+
+inline CSGStackOp get_stack_operation(const indexed_triangle_set *const part)
+{
+    return CSGStackOp::Continue;
+}
+
+inline const indexed_triangle_set * get_mesh(const indexed_triangle_set *const part)
+{
+    return part;
+}
+
+inline Transform3f get_transform(const indexed_triangle_set *const part)
+{
+    return Transform3f::Identity();
+}
+
+inline CSGType get_operation(const TriangleMesh &part)
+{
+    return CSGType::Union;
+}
+
+inline CSGStackOp get_stack_operation(const TriangleMesh &part)
+{
+    return CSGStackOp::Continue;
+}
+
+inline const indexed_triangle_set * get_mesh(const TriangleMesh &part)
+{
+    return &part.its;
+}
+
+inline Transform3f get_transform(const TriangleMesh &part)
+{
+    return Transform3f::Identity();
+}
+
+inline CSGType get_operation(const TriangleMesh * const part)
+{
+    return CSGType::Union;
+}
+
+inline CSGStackOp get_stack_operation(const TriangleMesh * const part)
+{
+    return CSGStackOp::Continue;
+}
+
+inline const indexed_triangle_set * get_mesh(const TriangleMesh * const part)
+{
+    return &part->its;
+}
+
+inline Transform3f get_transform(const TriangleMesh * const part)
+{
+    return Transform3f::Identity();
+}
+
+}} // namespace Slic3r::csg
+
+#endif // TRIANGLEMESHADAPTER_HPP

src/libslic3r/CSGMesh/VoxelizeCSGMesh.hpp

@@ -0,0 +1,116 @@
+#ifndef VOXELIZECSGMESH_HPP
+#define VOXELIZECSGMESH_HPP
+
+#include <functional>
+#include <stack>
+
+#include "CSGMesh.hpp"
+#include "libslic3r/OpenVDBUtils.hpp"
+#include "libslic3r/Execution/ExecutionTBB.hpp"
+
+namespace Slic3r { namespace csg {
+
+using VoxelizeParams = MeshToGridParams;
+
+// This method can be overriden when a specific CSGPart type supports caching
+// of the voxel grid
+template<class CSGPartT>
+VoxelGridPtr get_voxelgrid(const CSGPartT &csgpart, VoxelizeParams params)
+{
+    const indexed_triangle_set *its = csg::get_mesh(csgpart);
+    VoxelGridPtr ret;
+
+    params.trafo(params.trafo() * csg::get_transform(csgpart));
+
+    if (its)
+        ret = mesh_to_grid(*its, params);
+
+    return ret;
+}
+
+namespace detail {
+
+inline void perform_csg(CSGType op, VoxelGridPtr &dst, VoxelGridPtr &src)
+{
+    if (!dst || !src)
+        return;
+
+    switch (op) {
+    case CSGType::Union:
+        if (is_grid_empty(*dst) && !is_grid_empty(*src))
+            dst = clone(*src);
+        else
+            grid_union(*dst, *src);
+
+        break;
+    case CSGType::Difference:
+        grid_difference(*dst, *src);
+        break;
+    case CSGType::Intersection:
+        grid_intersection(*dst, *src);
+        break;
+    }
+}
+
+} // namespace detail
+
+template<class It>
+VoxelGridPtr voxelize_csgmesh(const Range<It>      &csgrange,
+                              const VoxelizeParams &params = {})
+{
+    using namespace detail;
+
+    VoxelGridPtr ret;
+
+    std::vector<VoxelGridPtr> grids (csgrange.size());
+
+    execution::for_each(ex_tbb, size_t(0), csgrange.size(), [&](size_t csgidx) {
+        if (params.statusfn() && params.statusfn()(-1))
+            return;
+
+        auto it = csgrange.begin();
+        std::advance(it, csgidx);
+        auto &csgpart = *it;
+        grids[csgidx] = get_voxelgrid(csgpart, params);
+    }, execution::max_concurrency(ex_tbb));
+
+    size_t csgidx = 0;
+    struct Frame { CSGType op = CSGType::Union; VoxelGridPtr grid; };
+    std::stack opstack{std::vector<Frame>{}};
+
+    opstack.push({CSGType::Union, mesh_to_grid({}, params)});
+
+    for (auto &csgpart : csgrange) {
+        if (params.statusfn() && params.statusfn()(-1))
+            break;
+
+        auto &partgrid = grids[csgidx++];
+
+        auto op = get_operation(csgpart);
+
+        if (get_stack_operation(csgpart) == CSGStackOp::Push) {
+            opstack.push({op, mesh_to_grid({}, params)});
+            op = CSGType::Union;
+        }
+
+        Frame *top = &opstack.top();
+
+        perform_csg(get_operation(csgpart), top->grid, partgrid);
+
+        if (get_stack_operation(csgpart) == CSGStackOp::Pop) {
+            VoxelGridPtr popgrid = std::move(top->grid);
+            auto popop = opstack.top().op;
+            opstack.pop();
+            VoxelGridPtr &grid = opstack.top().grid;
+            perform_csg(popop, grid, popgrid);
+        }
+    }
+
+    ret = std::move(opstack.top().grid);
+
+    return ret;
+}
+
+}} // namespace Slic3r::csg
+
+#endif // VOXELIZECSGMESH_HPP

src/libslic3r/ExtrusionEntity.hpp

@@ -52,7 +52,8 @@ enum ExtrusionLoopRole {
 inline bool is_perimeter(ExtrusionRole role)
 {
     return role == erPerimeter
-        || role == erExternalPerimeter;
+        || role == erExternalPerimeter
+        || role == erOverhangPerimeter;
 }
 
 inline bool is_internal_perimeter(ExtrusionRole role)
@@ -101,6 +102,8 @@ public:
     virtual bool is_collection() const { return false; }
     virtual bool is_loop() const { return false; }
     virtual bool can_reverse() const { return true; }
+    virtual bool can_sort() const { return true; }//BBS: only used in ExtrusionEntityCollection
+    virtual void set_reverse() {}
     virtual ExtrusionEntity* clone() const = 0;
     // Create a new object, initialize it with this object using the move semantics.
     virtual ExtrusionEntity* clone_move() = 0;
@@ -151,12 +154,53 @@ public:
     ExtrusionPath(ExtrusionRole role) : mm3_per_mm(-1), width(-1), height(-1), m_role(role), m_no_extrusion(false) {}
     ExtrusionPath(ExtrusionRole role, double mm3_per_mm, float width, float height, bool no_extrusion = false) : mm3_per_mm(mm3_per_mm), width(width), height(height), m_role(role), m_no_extrusion(no_extrusion) {}
     ExtrusionPath(int overhang_degree, int curve_degree, ExtrusionRole role, double mm3_per_mm, float width, float height) : overhang_degree(overhang_degree), curve_degree(curve_degree), mm3_per_mm(mm3_per_mm), width(width), height(height), m_role(role) {}
-    ExtrusionPath(const ExtrusionPath& rhs) : polyline(rhs.polyline), overhang_degree(rhs.overhang_degree), curve_degree(rhs.curve_degree), mm3_per_mm(rhs.mm3_per_mm), width(rhs.width), height(rhs.height), m_role(rhs.m_role), m_no_extrusion(rhs.m_no_extrusion) {}
+    ExtrusionPath(const ExtrusionPath &rhs)
-    ExtrusionPath(ExtrusionPath&& rhs) : polyline(std::move(rhs.polyline)), overhang_degree(rhs.overhang_degree), curve_degree(rhs.curve_degree), mm3_per_mm(rhs.mm3_per_mm), width(rhs.width), height(rhs.height), m_role(rhs.m_role), m_no_extrusion(rhs.m_no_extrusion) {}
+        : polyline(rhs.polyline)
-    ExtrusionPath(const Polyline &polyline, const ExtrusionPath &rhs) : polyline(polyline), overhang_degree(rhs.overhang_degree), curve_degree(rhs.curve_degree), mm3_per_mm(rhs.mm3_per_mm), width(rhs.width), height(rhs.height), m_role(rhs.m_role), m_no_extrusion(rhs.m_no_extrusion) {}
+        , overhang_degree(rhs.overhang_degree)
-    ExtrusionPath(Polyline &&polyline, const ExtrusionPath &rhs) : polyline(std::move(polyline)), overhang_degree(rhs.overhang_degree), curve_degree(rhs.curve_degree), mm3_per_mm(rhs.mm3_per_mm), width(rhs.width), height(rhs.height), m_role(rhs.m_role), m_no_extrusion(rhs.m_no_extrusion) {}
+        , curve_degree(rhs.curve_degree)
+        , mm3_per_mm(rhs.mm3_per_mm)
+        , width(rhs.width)
+        , height(rhs.height)
+        , m_can_reverse(rhs.m_can_reverse)
+        , m_role(rhs.m_role)
+        , m_no_extrusion(rhs.m_no_extrusion)
+    {}
+    ExtrusionPath(ExtrusionPath &&rhs)
+        : polyline(std::move(rhs.polyline))
+        , overhang_degree(rhs.overhang_degree)
+        , curve_degree(rhs.curve_degree)
+        , mm3_per_mm(rhs.mm3_per_mm)
+        , width(rhs.width)
+        , height(rhs.height)
+        , m_can_reverse(rhs.m_can_reverse)
+        , m_role(rhs.m_role)
+        , m_no_extrusion(rhs.m_no_extrusion)
+    {}
+    ExtrusionPath(const Polyline &polyline, const ExtrusionPath &rhs)
+        : polyline(polyline)
+        , overhang_degree(rhs.overhang_degree)
+        , curve_degree(rhs.curve_degree)
+        , mm3_per_mm(rhs.mm3_per_mm)
+        , width(rhs.width)
+        , height(rhs.height)
+        , m_can_reverse(rhs.m_can_reverse)
+        , m_role(rhs.m_role)
+        , m_no_extrusion(rhs.m_no_extrusion)
+    {}
+    ExtrusionPath(Polyline &&polyline, const ExtrusionPath &rhs)
+        : polyline(std::move(polyline))
+        , overhang_degree(rhs.overhang_degree)
+        , curve_degree(rhs.curve_degree)
+        , mm3_per_mm(rhs.mm3_per_mm)
+        , width(rhs.width)
+        , height(rhs.height)
+        , m_can_reverse(rhs.m_can_reverse)
+        , m_role(rhs.m_role)
+        , m_no_extrusion(rhs.m_no_extrusion)
+    {}
 
     ExtrusionPath& operator=(const ExtrusionPath& rhs) {
+        m_can_reverse = rhs.m_can_reverse;
         m_role = rhs.m_role;
         m_no_extrusion = rhs.m_no_extrusion;
         this->mm3_per_mm = rhs.mm3_per_mm;
@@ -168,6 +212,7 @@ public:
         return *this;
     }
     ExtrusionPath& operator=(ExtrusionPath&& rhs) {
+        m_can_reverse = rhs.m_can_reverse;
         m_role = rhs.m_role;
         m_no_extrusion = rhs.m_no_extrusion;
         this->mm3_per_mm = rhs.mm3_per_mm;
@@ -238,10 +283,12 @@ public:
     bool is_force_no_extrusion() const { return m_no_extrusion; }
     void set_force_no_extrusion(bool no_extrusion) { m_no_extrusion = no_extrusion; }
     void set_extrusion_role(ExtrusionRole extrusion_role) { m_role = extrusion_role; }
+    void set_reverse() override { m_can_reverse = false; }
+    bool can_reverse() const override { return m_can_reverse; }
 
 private:
     void _inflate_collection(const Polylines &polylines, ExtrusionEntityCollection* collection) const;
-
+    bool m_can_reverse = true;
     ExtrusionRole m_role;
     //BBS
     bool m_no_extrusion = false;
@@ -256,16 +303,27 @@ public:
     ExtrusionPaths paths;
 
     ExtrusionMultiPath() {}
-    ExtrusionMultiPath(const ExtrusionMultiPath &rhs) : paths(rhs.paths) {}
+    ExtrusionMultiPath(const ExtrusionMultiPath &rhs) : paths(rhs.paths), m_can_reverse(rhs.m_can_reverse) {}
-    ExtrusionMultiPath(ExtrusionMultiPath &&rhs) : paths(std::move(rhs.paths)) {}
+    ExtrusionMultiPath(ExtrusionMultiPath &&rhs) : paths(std::move(rhs.paths)), m_can_reverse(rhs.m_can_reverse) {}
     ExtrusionMultiPath(const ExtrusionPaths &paths) : paths(paths) {}
-    ExtrusionMultiPath(const ExtrusionPath &path) { this->paths.push_back(path); }
+    ExtrusionMultiPath(const ExtrusionPath &path) {this->paths.push_back(path); m_can_reverse = path.can_reverse(); }
 
-    ExtrusionMultiPath& operator=(const ExtrusionMultiPath &rhs) { this->paths = rhs.paths; return *this; }
+    ExtrusionMultiPath &operator=(const ExtrusionMultiPath &rhs)
-    ExtrusionMultiPath& operator=(ExtrusionMultiPath &&rhs) { this->paths = std::move(rhs.paths); return *this; }
+    {
+        this->paths   = rhs.paths;
+        m_can_reverse = rhs.m_can_reverse;
+        return *this;
+    }
+    ExtrusionMultiPath &operator=(ExtrusionMultiPath &&rhs)
+    {
+        this->paths   = std::move(rhs.paths);
+        m_can_reverse = rhs.m_can_reverse;
+        return *this;
+    }
 
     bool is_loop() const override { return false; }
-    bool can_reverse() const override { return true; }
+    bool can_reverse() const override { return m_can_reverse; }
+    void set_reverse() override { m_can_reverse = false; }
 	ExtrusionEntity* clone() const override { return new ExtrusionMultiPath(*this); }
     // Create a new object, initialize it with this object using the move semantics.
 	ExtrusionEntity* clone_move() override { return new ExtrusionMultiPath(std::move(*this)); }
@@ -298,6 +356,9 @@ public:
             append(dst, p.polyline.points);
     }
     double total_volume() const override { double volume =0.; for (const auto& path : paths) volume += path.total_volume(); return volume; }
+
+private:
+    bool m_can_reverse = true;
 };
 
 // Single continuous extrusion loop, possibly with varying extrusion thickness, extrusion height or bridging / non bridging.

src/libslic3r/ExtrusionEntityCollection.hpp

@@ -32,12 +32,17 @@ public:
     ExtrusionEntitiesPtr entities;     // we own these entities
     bool no_sort;
     ExtrusionEntityCollection(): no_sort(false) {}
-    ExtrusionEntityCollection(const ExtrusionEntityCollection &other) : no_sort(other.no_sort) { this->append(other.entities); }
+    ExtrusionEntityCollection(const ExtrusionEntityCollection &other) : no_sort(other.no_sort), is_reverse(other.is_reverse) { this->append(other.entities); }
-    ExtrusionEntityCollection(ExtrusionEntityCollection &&other) : entities(std::move(other.entities)), no_sort(other.no_sort) {}
+    ExtrusionEntityCollection(ExtrusionEntityCollection &&other) : entities(std::move(other.entities)), no_sort(other.no_sort), is_reverse(other.is_reverse) {}
     explicit ExtrusionEntityCollection(const ExtrusionPaths &paths);
     ExtrusionEntityCollection& operator=(const ExtrusionEntityCollection &other);
     ExtrusionEntityCollection& operator=(ExtrusionEntityCollection &&other)
-        { this->entities = std::move(other.entities); this->no_sort = other.no_sort; return *this; }
+    {
+        this->entities = std::move(other.entities);
+        this->no_sort  = other.no_sort;
+        is_reverse     = other.is_reverse;
+        return *this;
+    }
     ~ExtrusionEntityCollection() { clear(); }
     explicit operator ExtrusionPaths() const;
     
@@ -50,7 +55,15 @@ public:
         }
         return out;
     }
-    bool can_reverse() const override { return !this->no_sort; }
+    bool can_sort() const override { return !this->no_sort; }
+    bool can_reverse() const override
+    {
+        if (this->no_sort)
+            return false;
+        else
+            return is_reverse;
+    }
+    void set_reverse() override { is_reverse = false; }
     bool empty() const { return this->entities.empty(); }
     void clear();
     void swap (ExtrusionEntityCollection &c);
@@ -126,6 +139,9 @@ public:
         throw Slic3r::RuntimeError("Calling length() on a ExtrusionEntityCollection");
         return 0.;        
     }
+
+private:
+    bool is_reverse{true};
 };
 
 } // namespace Slic3r

src/libslic3r/Fill/Fill.cpp

@@ -157,7 +157,9 @@ std::vector<SurfaceFill> group_fills(const Layer &layer)
 		        if (surface.is_solid()) {
 		            params.density = 100.f;
 					//FIXME for non-thick bridges, shall we allow a bottom surface pattern?
-                    if (surface.is_external() && ! is_bridge) {
+					if (surface.is_solid_infill())
+                        params.pattern = region_config.internal_solid_infill_pattern.value;
+                    else if (surface.is_external() && ! is_bridge) {
                         if(surface.is_top())
                             params.pattern = region_config.top_surface_pattern.value;
                         else
@@ -199,7 +201,6 @@ std::vector<SurfaceFill> group_fills(const Layer &layer)
 					// so that internall infill will be aligned over all layers of the current region.
 		            params.spacing = layerm.region().flow(*layer.object(), frInfill, layer.object()->config().layer_height, false).spacing();
 		            // Anchor a sparse infill to inner perimeters with the following anchor length:
-					// Anchor a sparse infill to inner perimeters with the following anchor length:
 			        params.anchor_length = float(region_config.infill_anchor);
 					if (region_config.infill_anchor.percent)
 						params.anchor_length = float(params.anchor_length * 0.01 * params.spacing);
@@ -492,8 +493,9 @@ void Layer::make_fills(FillAdaptive::Octree* adaptive_fill_octree, FillAdaptive:
 		params.using_internal_flow = using_internal_flow;
 		params.no_extrusion_overlap = surface_fill.params.overlap;
 		params.with_loop = surface_fill.params.with_loop;
-
 		params.config = &layerm->region().config();
+		if (surface_fill.params.pattern == ipGrid)
+			params.can_reverse = false;
 		for (ExPolygon& expoly : surface_fill.expolygons) {
             f->no_overlap_expolygons = intersection_ex(surface_fill.no_overlap_expolygons, ExPolygons() = {expoly}, ApplySafetyOffset::Yes);
 			// Spacing is modified by the filler to indicate adjustments. Reset it for each expolygon.
@@ -538,6 +540,7 @@ void Layer::make_ironing()
 
 	// First classify regions based on the extruder used.
 	struct IroningParams {
+		InfillPattern pattern;
 		int 		extruder 	= -1;
 		bool 		just_infill = false;
 		// Spacing of the ironing lines, also to calculate the extrusion flow from.
@@ -577,8 +580,7 @@ void Layer::make_ironing()
 
 		bool operator==(const IroningParams &rhs) const {
 			return this->extruder == rhs.extruder && this->just_infill == rhs.just_infill &&
-				   this->line_spacing == rhs.line_spacing && this->height == rhs.height && this->speed == rhs.speed &&
+				   this->line_spacing == rhs.line_spacing && this->height == rhs.height && this->speed == rhs.speed && this->angle == rhs.angle && this->pattern == rhs.pattern;
-				   this->angle == rhs.angle;
 		}
 
 		LayerRegion *layerm		= nullptr;
@@ -625,24 +627,36 @@ void Layer::make_ironing()
 				ironing_params.height 		= default_layer_height * 0.01 * config.ironing_flow;
 				ironing_params.speed 		= config.ironing_speed;
 				ironing_params.angle 		= config.infill_direction * M_PI / 180.;
+				ironing_params.pattern      = config.ironing_pattern;
 				ironing_params.layerm 		= layerm;
 				by_extruder.emplace_back(ironing_params);
 			}
 		}
 	std::sort(by_extruder.begin(), by_extruder.end());
 
-    FillRectilinear 	fill;
     FillParams 			fill_params;
-	fill.set_bounding_box(this->object()->bounding_box());
-	fill.layer_id 			 = this->id();
-    fill.z 					 = this->print_z;
-    fill.overlap 			 = 0;
     fill_params.density 	 = 1.;
     fill_params.monotonic    = true;
-
+    InfillPattern         f_pattern = ipRectilinear;
+    std::unique_ptr<Fill> f         = std::unique_ptr<Fill>(Fill::new_from_type(f_pattern));
+    f->set_bounding_box(this->object()->bounding_box());
+    f->layer_id = this->id();
+    f->z        = this->print_z;
+    f->overlap  = 0;
 	for (size_t i = 0; i < by_extruder.size();) {
 		// Find span of regions equivalent to the ironing operation.
 		IroningParams &ironing_params = by_extruder[i];
+		// Create the filler object.
+		if( f_pattern != ironing_params.pattern )
+		{
+            f_pattern               = ironing_params.pattern;
+            f = std::unique_ptr<Fill>(Fill::new_from_type(f_pattern));
+            f->set_bounding_box(this->object()->bounding_box());
+            f->layer_id = this->id();
+            f->z        = this->print_z;
+            f->overlap  = 0;
+		}
+
 		size_t j = i;
 		for (++ j; j < by_extruder.size() && ironing_params == by_extruder[j]; ++ j) ;
 
@@ -704,10 +718,10 @@ void Layer::make_ironing()
 		}
 
         // Create the filler object.
-        fill.spacing = ironing_params.line_spacing;
+        f->spacing = ironing_params.line_spacing;
-        fill.angle = float(ironing_params.angle + 0.25 * M_PI);
+        f->angle = float(ironing_params.angle + 0.25 * M_PI);
-        fill.link_max_length = (coord_t)scale_(3. * fill.spacing);
+        f->link_max_length = (coord_t) scale_(3. * f->spacing);
-		double extrusion_height = ironing_params.height * fill.spacing / nozzle_dmr;
+		double  extrusion_height = ironing_params.height * f->spacing / nozzle_dmr;
 		float  extrusion_width  = Flow::rounded_rectangle_extrusion_width_from_spacing(float(nozzle_dmr), float(extrusion_height));
 		double flow_mm3_per_mm = nozzle_dmr * extrusion_height;
         Surface surface_fill(stTop, ExPolygon());
@@ -715,7 +729,7 @@ void Layer::make_ironing()
 			surface_fill.expolygon = std::move(expoly);
 			Polylines polylines;
 			try {
-				polylines = fill.fill_surface(&surface_fill, fill_params);
+				polylines = f->fill_surface(&surface_fill, fill_params);
 			} catch (InfillFailedException &) {
 			}
 	        if (! polylines.empty()) {

src/libslic3r/Fill/FillBase.cpp

@@ -192,6 +192,7 @@ void Fill::fill_surface_extrusion(const Surface* surface, const FillParams& para
         out.push_back(eec = new ExtrusionEntityCollection());
         // Only concentric fills are not sorted.
         eec->no_sort = this->no_sort();
+        size_t idx   = eec->entities.size();
         if (params.use_arachne) {
             Flow new_flow = params.flow.with_spacing(float(this->spacing));
             variable_width(thick_polylines, params.extrusion_role, new_flow, eec->entities);
@@ -203,6 +204,10 @@ void Fill::fill_surface_extrusion(const Surface* surface, const FillParams& para
                 params.extrusion_role,
                 flow_mm3_per_mm, float(flow_width), params.flow.height());
         }
+        if (!params.can_reverse) {
+            for (size_t i = idx; i < eec->entities.size(); i++)
+                eec->entities[i]->set_reverse();
+        }
     }
 }
 

src/libslic3r/Fill/FillBase.hpp

@@ -78,6 +78,7 @@ struct FillParams
     float           no_extrusion_overlap{ 0.0 };
     const           PrintRegionConfig* config{ nullptr };
     bool            dont_sort{ false }; // do not sort the lines, just simply connect them
+    bool            can_reverse{true};
 };
 static_assert(IsTriviallyCopyable<FillParams>::value, "FillParams class is not POD (and it should be - see constructor).");
 

src/libslic3r/Fill/FillRectilinear.cpp

@@ -2994,6 +2994,10 @@ Polylines FillGrid::fill_surface(const Surface *surface, const FillParams &param
             { { 0.f, 0.f }, { float(M_PI / 2.), 0.f } },
             polylines_out))
         BOOST_LOG_TRIVIAL(error) << "FillGrid::fill_surface() failed to fill a region.";
+
+    if (this->layer_id % 2 == 1)
+        for (int i = 0; i < polylines_out.size(); i++)
+            std::reverse(polylines_out[i].begin(), polylines_out[i].end());
     return polylines_out;
 }
 

src/libslic3r/FlushVolCalc.cpp

@@ -0,0 +1,98 @@
+#include <cmath>
+#include <assert.h>
+#include "slic3r/Utils/ColorSpaceConvert.hpp"
+
+#include "FlushVolCalc.hpp"
+
+
+namespace Slic3r {
+
+const int g_min_flush_volume_from_support = 420.f;
+const int g_flush_volume_to_support = 230;
+
+const int g_max_flush_volume = 800;
+
+static float to_radians(float degree)
+{
+    return degree / 180.f * M_PI;
+}
+
+
+static float get_luminance(float r, float g, float b)
+{
+    return r * 0.3 + g * 0.59 + b * 0.11;
+}
+
+static float calc_triangle_3rd_edge(float edge_a, float edge_b, float degree_ab)
+{
+    return std::sqrt(edge_a * edge_a + edge_b * edge_b - 2 * edge_a * edge_b * std::cos(to_radians(degree_ab)));
+}
+
+static float DeltaHS_BBS(float h1, float s1, float v1, float h2, float s2, float v2)
+{
+    float h1_rad = to_radians(h1);
+    float h2_rad = to_radians(h2);
+
+    float dx = std::cos(h1_rad) * s1 * v1 - cos(h2_rad) * s2 * v2;
+    float dy = std::sin(h1_rad) * s1 * v1 - sin(h2_rad) * s2 * v2;
+    float dxy = std::sqrt(dx * dx + dy * dy);
+    return std::min(1.2f, dxy);
+}
+
+FlushVolCalculator::FlushVolCalculator(int min, int max, float multiplier)
+    :m_min_flush_vol(min), m_max_flush_vol(max), m_multiplier(multiplier)
+{
+}
+
+int FlushVolCalculator::calc_flush_vol(unsigned char src_a, unsigned char src_r, unsigned char src_g, unsigned char src_b,
+    unsigned char dst_a, unsigned char dst_r, unsigned char dst_g, unsigned char dst_b)
+{
+    // BBS: Transparent materials are treated as white materials
+    if (src_a == 0) {
+        src_r = src_g = src_b = 255;
+    }
+    if (dst_a == 0) {
+        dst_r = dst_g = dst_b = 255;
+    }
+
+    float src_r_f, src_g_f, src_b_f, dst_r_f, dst_g_f, dst_b_f;
+    float from_hsv_h, from_hsv_s, from_hsv_v;
+    float to_hsv_h, to_hsv_s, to_hsv_v;
+
+    src_r_f = (float)src_r / 255.f;
+    src_g_f = (float)src_g / 255.f;
+    src_b_f = (float)src_b / 255.f;
+    dst_r_f = (float)dst_r / 255.f;
+    dst_g_f = (float)dst_g / 255.f;
+    dst_b_f = (float)dst_b / 255.f;
+
+    // Calculate color distance in HSV color space
+    RGB2HSV(src_r_f, src_g_f,src_b_f, &from_hsv_h, &from_hsv_s, &from_hsv_v);
+    RGB2HSV(dst_r_f, dst_g_f, dst_b_f, &to_hsv_h, &to_hsv_s, &to_hsv_v);
+    float hs_dist = DeltaHS_BBS(from_hsv_h, from_hsv_s, from_hsv_v, to_hsv_h, to_hsv_s, to_hsv_v);
+
+    // 1. Color difference is more obvious if the dest color has high luminance
+    // 2. Color difference is more obvious if the source color has low luminance
+    float from_lumi = get_luminance(src_r_f, src_g_f, src_b_f);
+    float to_lumi = get_luminance(dst_r_f, dst_g_f, dst_b_f);
+    float lumi_flush = 0.f;
+    if (to_lumi >= from_lumi) {
+        lumi_flush = std::pow(to_lumi - from_lumi, 0.7f) * 560.f;
+    }
+    else {
+        lumi_flush = (from_lumi - to_lumi) * 80.f;
+
+        float inter_hsv_v = 0.67 * to_hsv_v + 0.33 * from_hsv_v;
+        hs_dist = std::min(inter_hsv_v, hs_dist);
+    }
+    float hs_flush = 230.f * hs_dist;
+
+    float flush_volume = calc_triangle_3rd_edge(hs_flush, lumi_flush, 120.f);
+    flush_volume = std::max(flush_volume, 60.f);
+
+    //float flush_multiplier = std::atof(m_flush_multiplier_ebox->GetValue().c_str());
+    flush_volume += m_min_flush_vol;
+    return std::min((int)flush_volume, m_max_flush_vol);
+}
+
+}

src/libslic3r/FlushVolCalc.hpp

@@ -0,0 +1,34 @@
+#ifndef slic3r_FlushVolCalc_hpp_
+#define slic3r_FlushVolCalc_hpp_
+
+#include "libslic3r.h"
+#include "Config.hpp"
+
+
+namespace Slic3r {
+
+extern const int g_min_flush_volume_from_support;
+extern const int g_flush_volume_to_support;
+extern const int g_max_flush_volume;
+
+class FlushVolCalculator
+{
+public:
+    FlushVolCalculator(int min, int max, float multiplier = 1.0f);
+    ~FlushVolCalculator()
+    {
+    }
+
+    int calc_flush_vol(unsigned char src_a, unsigned char src_r, unsigned char src_g, unsigned char src_b,
+        unsigned char dst_a, unsigned char dst_r, unsigned char dst_g, unsigned char dst_b);
+
+private:
+    int m_min_flush_vol;
+    int m_max_flush_vol;
+    float m_multiplier;
+};
+
+
+}
+
+#endif

src/libslic3r/Format/OBJ.cpp

@@ -15,9 +15,13 @@
 #define DIR_SEPARATOR '/'
 #endif
 
+//Translation
+#include "I18N.hpp"
+#define _L(s) Slic3r::I18N::translate(s)
+
 namespace Slic3r {
 
-bool load_obj(const char *path, TriangleMesh *meshptr)
+bool load_obj(const char *path, TriangleMesh *meshptr, std::string &message)
 {
     if (meshptr == nullptr)
         return false;
@@ -26,6 +30,7 @@ bool load_obj(const char *path, TriangleMesh *meshptr)
     ObjParser::ObjData data;
     if (! ObjParser::objparse(path, data)) {
         BOOST_LOG_TRIVIAL(error) << "load_obj: failed to parse " << path;
+        message = _L("load_obj: failed to parse");
         return false;
     }
     
@@ -40,10 +45,12 @@ bool load_obj(const char *path, TriangleMesh *meshptr)
             if (num_face_vertices > 4) {
                 // Non-triangular and non-quad faces are not supported as of now.
                 BOOST_LOG_TRIVIAL(error) << "load_obj: failed to parse " << path << ". The file contains polygons with more than 4 vertices.";
+                message = _L("The file contains polygons with more than 4 vertices.");
                 return false;
             } else if (num_face_vertices < 3) {
                 // Non-triangular and non-quad faces are not supported as of now.
                 BOOST_LOG_TRIVIAL(error) << "load_obj: failed to parse " << path << ". The file contains polygons with less than 2 vertices.";
+                message = _L("The file contains polygons with less than 2 vertices.");
                 return false;
             }
             if (num_face_vertices == 4)
@@ -75,6 +82,7 @@ bool load_obj(const char *path, TriangleMesh *meshptr)
                     assert(cnt < 4);
                     if (vertex.coordIdx < 0 || vertex.coordIdx >= int(its.vertices.size())) {
                         BOOST_LOG_TRIVIAL(error) << "load_obj: failed to parse " << path << ". The file contains invalid vertex index.";
+                        message = _L("The file contains invalid vertex index.");
                         return false;
                     }
                     indices[cnt ++] = vertex.coordIdx;
@@ -91,6 +99,7 @@ bool load_obj(const char *path, TriangleMesh *meshptr)
     *meshptr = TriangleMesh(std::move(its));
     if (meshptr->empty()) {
         BOOST_LOG_TRIVIAL(error) << "load_obj: This OBJ file couldn't be read because it's empty. " << path;
+        message = _L("This OBJ file couldn't be read because it's empty.");
         return false;
     }
     if (meshptr->volume() < 0)
@@ -98,11 +107,11 @@ bool load_obj(const char *path, TriangleMesh *meshptr)
     return true;
 }
 
-bool load_obj(const char *path, Model *model, const char *object_name_in)
+bool load_obj(const char *path, Model *model, std::string &message, const char *object_name_in)
 {
     TriangleMesh mesh;
     
-    bool ret = load_obj(path, &mesh);
+    bool ret = load_obj(path, &mesh, message);
     
     if (ret) {
         std::string  object_name;

src/libslic3r/Format/OBJ.hpp

@@ -8,8 +8,8 @@ class Model;
 class ModelObject;
 
 // Load an OBJ file into a provided model.
-extern bool load_obj(const char *path, TriangleMesh *mesh);
+extern bool load_obj(const char *path, TriangleMesh *mesh, std::string &message);
-extern bool load_obj(const char *path, Model *model, const char *object_name = nullptr);
+extern bool load_obj(const char *path, Model *model, std::string &message, const char *object_name = nullptr);
 
 extern bool store_obj(const char *path, TriangleMesh *mesh);
 extern bool store_obj(const char *path, ModelObject *model);

src/libslic3r/Format/STEP.cpp

@@ -28,7 +28,7 @@
 #include "TopExp_Explorer.hxx"
 #include "BRep_Tool.hxx"
 
-const double STEP_TRANS_CHORD_ERROR = 0.0025;
+const double STEP_TRANS_CHORD_ERROR = 0.003;
 const double STEP_TRANS_ANGLE_RES = 0.5;
 
 

src/libslic3r/Format/bbs_3mf.hpp

@@ -24,7 +24,9 @@ struct ThumbnailData;
 #define EMBEDDED_FILAMENT_FILE_FORMAT      "Metadata/filament_settings_%1%.config"
 #define EMBEDDED_PRINTER_FILE_FORMAT      "Metadata/machine_settings_%1%.config"
 
+#define BBL_DESIGNER_MODEL_TITLE_TAG     "Title"
 #define BBL_DESIGNER_PROFILE_ID_TAG      "DesignProfileId"
+#define BBL_DESIGNER_PROFILE_TITLE_TAG   "ProfileTitle"
 #define BBL_DESIGNER_MODEL_ID_TAG        "DesignModelId"
 
 
@@ -76,10 +78,12 @@ struct PlateData
     std::string     gcode_weight;
     std::string     plate_name;
     std::vector<FilamentInfo> slice_filaments_info;
+    std::vector<size_t> skipped_objects;
     DynamicPrintConfig config;
     bool            is_support_used {false};
     bool            is_sliced_valid = false;
     bool            toolpath_outside {false};
+    bool            is_label_object_enabled {false};
 
     std::vector<GCodeProcessorResult::SliceWarning> warnings;
 
@@ -108,6 +112,7 @@ enum class SaveStrategy
     WithSliceInfo       = 1 << 8,
     SkipAuxiliary       = 1 << 9,
     UseLoadedId         = 1 << 10,
+    ShareMesh           = 1 << 11,
 
     SplitModel = 0x1000 | ProductionExt,
     Encrypted  = SecureContentExt | SplitModel,
@@ -221,6 +226,10 @@ extern bool load_bbs_3mf(const char* path, DynamicPrintConfig* config, ConfigSub
 
 extern std::string bbs_3mf_get_thumbnail(const char * path);
 
+extern bool load_gcode_3mf_from_stream(std::istream & data, DynamicPrintConfig* config, Model* model, PlateDataPtrs* plate_data_list, 
+       Semver* file_version);
+
+
 //BBS: add plate data list related logic
 // add backup logic
 // Save the given model and the config data contained in the given Print into a 3mf file.

src/libslic3r/GCode/ConflictChecker.cpp

@@ -89,14 +89,10 @@ inline Grids line_rasterization(const Line &line, int64_t xdist = RasteXDistance
 }
 } // namespace RasterizationImpl
 
-void LinesBucketQueue::emplace_back_bucket(std::vector<ExtrusionPaths> &&paths, const void *objPtr, Point offset)
+void LinesBucketQueue::emplace_back_bucket(ExtrusionLayers &&els, const void *objPtr, Point offset)
 {
     auto oldSize = _buckets.capacity();
-    if (_objsPtrToId.find(objPtr) == _objsPtrToId.end()) {
+    _buckets.emplace_back(std::move(els), objPtr, offset);
-        _objsPtrToId.insert({objPtr, _objsPtrToId.size()});
-        _idToObjsPtr.insert({_objsPtrToId.size() - 1, objPtr});
-    }
-    _buckets.emplace_back(std::move(paths), _objsPtrToId[objPtr], offset);
     _pq.push(&_buckets.back());
     auto newSize = _buckets.capacity();
     if (oldSize != newSize) { // pointers change
@@ -106,15 +102,16 @@ void LinesBucketQueue::emplace_back_bucket(std::vector<ExtrusionPaths> &&paths,
     }
 }
 
-double LinesBucketQueue::removeLowests()
+// remove lowest and get the current bottom z
+float LinesBucketQueue::getCurrBottomZ()
 {
     auto lowest = _pq.top();
     _pq.pop();
-    double                     curHeight = lowest->curHeight();
+    float                      layerBottomZ = lowest->curBottomZ();
     std::vector<LinesBucket *> lowests;
     lowests.push_back(lowest);
 
-    while (_pq.empty() == false && std::abs(_pq.top()->curHeight() - lowest->curHeight()) < EPSILON) {
+    while (_pq.empty() == false && std::abs(_pq.top()->curBottomZ() - lowest->curBottomZ()) < EPSILON) {
         lowests.push_back(_pq.top());
         _pq.pop();
     }
@@ -123,7 +120,7 @@ double LinesBucketQueue::removeLowests()
         bp->raise();
         if (bp->valid()) { _pq.push(bp); }
     }
-    return curHeight;
+    return layerBottomZ;
 }
 
 LineWithIDs LinesBucketQueue::getCurLines() const
@@ -156,32 +153,44 @@ void getExtrusionPathsFromEntity(const ExtrusionEntityCollection *entity, Extrus
     getExtrusionPathImpl(entity, paths);
 }
 
-ExtrusionPaths getExtrusionPathsFromLayer(LayerRegionPtrs layerRegionPtrs)
+ExtrusionLayers getExtrusionPathsFromLayer(const LayerRegionPtrs layerRegionPtrs)
 {
-    ExtrusionPaths paths;
+    ExtrusionLayers perimeters; // periments and infills
-    for (auto regionPtr : layerRegionPtrs) {
+    perimeters.resize(layerRegionPtrs.size());
-        getExtrusionPathsFromEntity(&regionPtr->perimeters, paths);
+    int i = 0;
-        if (regionPtr->perimeters.empty() == false) { getExtrusionPathsFromEntity(&regionPtr->fills, paths); }
+    for (LayerRegion *regionPtr : layerRegionPtrs) {
+        perimeters[i].layer    = regionPtr->layer();
+        perimeters[i].bottom_z = regionPtr->layer()->bottom_z();
+        perimeters[i].height   = regionPtr->layer()->height;
+        getExtrusionPathsFromEntity(&regionPtr->perimeters, perimeters[i].paths);
+        getExtrusionPathsFromEntity(&regionPtr->fills, perimeters[i].paths);
+        ++i;
     }
-    return paths;
+    return perimeters;
 }
 
-ExtrusionPaths getExtrusionPathsFromSupportLayer(SupportLayer *supportLayer)
+ExtrusionLayer getExtrusionPathsFromSupportLayer(SupportLayer *supportLayer)
 {
-    ExtrusionPaths paths;
+    ExtrusionLayer el;
-    getExtrusionPathsFromEntity(&supportLayer->support_fills, paths);
+    getExtrusionPathsFromEntity(&supportLayer->support_fills, el.paths);
-    return paths;
+    el.layer    = supportLayer;
+    el.bottom_z = supportLayer->bottom_z();
+    el.height   = supportLayer->height;
+    return el;
 }
 
-std::pair<std::vector<ExtrusionPaths>, std::vector<ExtrusionPaths>> getAllLayersExtrusionPathsFromObject(PrintObject *obj)
+ObjectExtrusions getAllLayersExtrusionPathsFromObject(PrintObject *obj)
 {
-    std::vector<ExtrusionPaths> objPaths, supportPaths;
+    ObjectExtrusions oe;
 
-    for (auto layerPtr : obj->layers()) { objPaths.push_back(getExtrusionPathsFromLayer(layerPtr->regions())); }
+    for (auto layerPtr : obj->layers()) {
+        auto perimeters = getExtrusionPathsFromLayer(layerPtr->regions());
+        oe.perimeters.insert(oe.perimeters.end(), perimeters.begin(), perimeters.end());
+    }
 
-    for (auto supportLayerPtr : obj->support_layers()) { supportPaths.push_back(getExtrusionPathsFromSupportLayer(supportLayerPtr)); }
+    for (auto supportLayerPtr : obj->support_layers()) { oe.support.push_back(getExtrusionPathsFromSupportLayer(supportLayerPtr)); }
 
-    return {std::move(objPaths), std::move(supportPaths)};
+    return oe;
 }
 
 ConflictComputeOpt ConflictChecker::find_inter_of_lines(const LineWithIDs &lines)
@@ -205,72 +214,90 @@ ConflictComputeOpt ConflictChecker::find_inter_of_lines(const LineWithIDs &lines
 }
 
 ConflictResultOpt ConflictChecker::find_inter_of_lines_in_diff_objs(PrintObjectPtrs                      objs,
-                                                                  std::optional<const FakeWipeTower *> wtdptr) // find the first intersection point of lines in different objects
+                                                                    std::optional<const FakeWipeTower *> wtdptr) // find the first intersection point of lines in different objects
 {
-    if (objs.size() <= 1) { return {}; }
+    if (objs.size() <= 1 && !wtdptr) { return {}; }
     LinesBucketQueue conflictQueue;
     if (wtdptr.has_value()) { // wipe tower at 0 by default
-        auto wtpaths = wtdptr.value()->getFakeExtrusionPathsFromWipeTower();
+        auto            wtpaths = wtdptr.value()->getFakeExtrusionPathsFromWipeTower();
-        conflictQueue.emplace_back_bucket(std::move(wtpaths), wtdptr.value(), {wtdptr.value()->plate_origin.x(),wtdptr.value()->plate_origin.y()});
+        ExtrusionLayers wtels;
+        wtels.type = ExtrusionLayersType::WIPE_TOWER;
+        for (int i = 0; i < wtpaths.size(); ++i) { // assume that wipe tower always has same height
+            ExtrusionLayer el;
+            el.paths    = wtpaths[i];
+            el.bottom_z = wtpaths[i].front().height * (float) i;
+            el.layer    = nullptr;
+            wtels.push_back(el);
+        }
+        conflictQueue.emplace_back_bucket(std::move(wtels), wtdptr.value(), {wtdptr.value()->plate_origin.x(), wtdptr.value()->plate_origin.y()});
     }
     for (PrintObject *obj : objs) {
         auto layers = getAllLayersExtrusionPathsFromObject(obj);
-        conflictQueue.emplace_back_bucket(std::move(layers.first), obj, obj->instances().front().shift);
+        conflictQueue.emplace_back_bucket(std::move(layers.perimeters), obj, obj->instances().front().shift);
-        conflictQueue.emplace_back_bucket(std::move(layers.second), obj, obj->instances().front().shift);
+        conflictQueue.emplace_back_bucket(std::move(layers.support), obj, obj->instances().front().shift);
     }
 
     std::vector<LineWithIDs> layersLines;
-    std::vector<double>      heights;
+    std::vector<float>       bottomZs;
     while (conflictQueue.valid()) {
-        LineWithIDs lines     = conflictQueue.getCurLines();
+        LineWithIDs lines = conflictQueue.getCurLines();
-        double      curHeight = conflictQueue.removeLowests();
+        float curBottomZ = conflictQueue.getCurrBottomZ();
-        heights.push_back(curHeight);
+        bottomZs.push_back(curBottomZ);
         layersLines.push_back(std::move(lines));
     }
 
-    bool                                   find = false;
+    bool                                                          find = false;
-    tbb::concurrent_vector<std::pair<ConflictComputeResult,double>> conflict;
+    tbb::concurrent_vector<std::pair<ConflictComputeResult, float>> conflict;
-
     tbb::parallel_for(tbb::blocked_range<size_t>(0, layersLines.size()), [&](tbb::blocked_range<size_t> range) {
         for (size_t i = range.begin(); i < range.end(); i++) {
             auto interRes = find_inter_of_lines(layersLines[i]);
             if (interRes.has_value()) {
                 find = true;
-                conflict.emplace_back(interRes.value(),heights[i]);
+                conflict.emplace_back(interRes.value(), bottomZs[i]);
                 break;
             }
         }
     });
 
     if (find) {
-        const void *ptr1           = conflictQueue.idToObjsPtr(conflict[0].first._obj1);
+        const void *ptr1           = conflict[0].first._obj1;
-        const void *ptr2           = conflictQueue.idToObjsPtr(conflict[0].first._obj2);
+        const void *ptr2           = conflict[0].first._obj2;
-        double      conflictHeight = conflict[0].second;
+        float       conflictPrintZ = conflict[0].second;
         if (wtdptr.has_value()) {
             const FakeWipeTower *wtdp = wtdptr.value();
             if (ptr1 == wtdp || ptr2 == wtdp) {
                 if (ptr2 == wtdp) { std::swap(ptr1, ptr2); }
                 const PrintObject *obj2 = reinterpret_cast<const PrintObject *>(ptr2);
-                return std::make_optional<ConflictResult>("WipeTower", obj2->model_object()->name, conflictHeight, nullptr, ptr2);
+                return std::make_optional<ConflictResult>("WipeTower", obj2->model_object()->name, conflictPrintZ, nullptr, ptr2);
             }
         }
         const PrintObject *obj1 = reinterpret_cast<const PrintObject *>(ptr1);
         const PrintObject *obj2 = reinterpret_cast<const PrintObject *>(ptr2);
-        return std::make_optional<ConflictResult>(obj1->model_object()->name, obj2->model_object()->name, conflictHeight, ptr1, ptr2);
+        return std::make_optional<ConflictResult>(obj1->model_object()->name, obj2->model_object()->name, conflictPrintZ, ptr1, ptr2);
     } else
         return {};
 }
 
 ConflictComputeOpt ConflictChecker::line_intersect(const LineWithID &l1, const LineWithID &l2)
 {
+    constexpr double SUPPORT_THRESHOLD = 100;  // this large almost disables conflict check of supports
+    constexpr double OTHER_THRESHOLD   = 0.01;
     if (l1._id == l2._id) { return {}; } // return true if lines are from same object
     Point inter;
     bool  intersect = l1._line.intersection(l2._line, &inter);
+
     if (intersect) {
-        auto dist1 = std::min(unscale(Point(l1._line.a - inter)).norm(), unscale(Point(l1._line.b - inter)).norm());
+        double dist1 = std::min(unscale(Point(l1._line.a - inter)).norm(), unscale(Point(l1._line.b - inter)).norm());
-        auto dist2 = std::min(unscale(Point(l2._line.a - inter)).norm(), unscale(Point(l2._line.b - inter)).norm());
+        double dist2 = std::min(unscale(Point(l2._line.a - inter)).norm(), unscale(Point(l2._line.b - inter)).norm());
-        auto dist  = std::min(dist1, dist2);
+        double dist  = std::min(dist1, dist2);
-        if (dist > 0.01) { return std::make_optional<ConflictComputeResult>(l1._id, l2._id); } // the two lines intersects if dist>0.01mm
+        ExtrusionRole r1        = l1._role;
+        ExtrusionRole r2        = l2._role;
+        bool          both_support = r1 == ExtrusionRole::erSupportMaterial || r1 == ExtrusionRole::erSupportMaterialInterface || r1 == ExtrusionRole::erSupportTransition;
+        both_support = both_support && ( r2 == ExtrusionRole::erSupportMaterial || r2 == ExtrusionRole::erSupportMaterialInterface || r2 == ExtrusionRole::erSupportTransition);
+        if (dist > (both_support ? SUPPORT_THRESHOLD:OTHER_THRESHOLD)) {
+            // the two lines intersects if dist>0.01mm for regular lines, and if dist>1mm for both supports
+            return std::make_optional<ConflictComputeResult>(l1._id, l2._id);
+        }
     }
     return {};
 }

src/libslic3r/GCode/ConflictChecker.hpp

@@ -14,55 +14,91 @@ namespace Slic3r {
 
 struct LineWithID
 {
-    Line _line;
+    Line          _line;
-    int  _id;
+    const void *  _id;
-    int  _role;
+    ExtrusionRole _role;
 
-    LineWithID(const Line &line, int id, int role) : _line(line), _id(id), _role(role) {}
+    LineWithID(const Line &line, const void* id, ExtrusionRole role) : _line(line), _id(id), _role(role) {}
 };
 
 using LineWithIDs = std::vector<LineWithID>;
 
+struct ExtrusionLayer
+{
+    ExtrusionPaths paths;
+    const Layer *  layer;
+    float          bottom_z;
+    float          height;
+};
+
+enum class ExtrusionLayersType { INFILL, PERIMETERS, SUPPORT, WIPE_TOWER };
+
+struct ExtrusionLayers : public std::vector<ExtrusionLayer>
+{
+    ExtrusionLayersType type;
+};
+
+struct ObjectExtrusions
+{
+    ExtrusionLayers perimeters;
+    ExtrusionLayers support;
+
+    ObjectExtrusions()
+    {
+        perimeters.type = ExtrusionLayersType::PERIMETERS;
+        support.type    = ExtrusionLayersType::SUPPORT;
+    }
+};
+
 class LinesBucket
 {
-private:
+public:
-    double   _curHeight  = 0.0;
+    float    _curBottomZ = 0.0;
     unsigned _curPileIdx = 0;
 
-    std::vector<ExtrusionPaths> _piles;
+    ExtrusionLayers _piles;
-    int                         _id;
+    const void*     _id;
-    Point                       _offset;
+    Point           _offset;
 
 public:
-    LinesBucket(std::vector<ExtrusionPaths> &&paths, int id, Point offset) : _piles(paths), _id(id), _offset(offset) {}
+    LinesBucket(ExtrusionLayers &&paths, const void* id, Point offset) : _piles(paths), _id(id), _offset(offset) {}
     LinesBucket(LinesBucket &&) = default;
 
+    std::pair<int, int> curRange() const
+    {
+        auto begin = std::lower_bound(_piles.begin(), _piles.end(), _piles[_curPileIdx], [](const ExtrusionLayer &l, const ExtrusionLayer &r) { return l.bottom_z < r.bottom_z; });
+        auto end = std::upper_bound(_piles.begin(), _piles.end(), _piles[_curPileIdx], [](const ExtrusionLayer &l, const ExtrusionLayer &r) { return l.bottom_z < r.bottom_z; });
+        return std::make_pair<int, int>(std::distance(_piles.begin(), begin), std::distance(_piles.begin(), end));
+    }
     bool valid() const { return _curPileIdx < _piles.size(); }
     void raise()
     {
-        if (valid()) {
+        if (!valid()) { return; }
-            if (_piles[_curPileIdx].empty() == false) { _curHeight += _piles[_curPileIdx].front().height; }
+        auto [b, e] = curRange();
-            _curPileIdx++;
+        _curPileIdx += (e - b);
-        }
+        _curBottomZ = _curPileIdx == _piles.size() ? _piles.back().bottom_z : _piles[_curPileIdx].bottom_z;
     }
-    double      curHeight() const { return _curHeight; }
+    float curBottomZ() const { return _curBottomZ; }
     LineWithIDs curLines() const
     {
+        auto [b, e] = curRange();
         LineWithIDs lines;
-        for (const ExtrusionPath &path : _piles[_curPileIdx]) {
+        for (int i = b; i < e; ++i) {
-            if (path.is_force_no_extrusion() == false) {
+            for (const ExtrusionPath &path : _piles[i].paths) {
-                Polyline check_polyline = path.polyline;
+                if (path.is_force_no_extrusion() == false) {
-                check_polyline.translate(_offset);
+                    Polyline check_polyline = path.polyline;
-                Lines tmpLines = check_polyline.lines();
+                    check_polyline.translate(_offset);
-                for (const Line &line : tmpLines) { lines.emplace_back(line, _id, path.role()); }
+                    Lines tmpLines = check_polyline.lines();
+                    for (const Line &line : tmpLines) { lines.emplace_back(line, _id, path.role()); }
+                }
             }
         }
         return lines;
     }
 
-    friend bool operator>(const LinesBucket &left, const LinesBucket &right) { return left._curHeight > right._curHeight; }
+    friend bool operator>(const LinesBucket &left, const LinesBucket &right) { return left._curBottomZ > right._curBottomZ; }
-    friend bool operator<(const LinesBucket &left, const LinesBucket &right) { return left._curHeight < right._curHeight; }
+    friend bool operator<(const LinesBucket &left, const LinesBucket &right) { return left._curBottomZ < right._curBottomZ; }
-    friend bool operator==(const LinesBucket &left, const LinesBucket &right) { return left._curHeight == right._curHeight; }
+    friend bool operator==(const LinesBucket &left, const LinesBucket &right) { return left._curBottomZ == right._curBottomZ; }
 };
 
 struct LinesBucketPtrComp
@@ -72,40 +108,31 @@ struct LinesBucketPtrComp
 
 class LinesBucketQueue
 {
-private:
+public:
     std::vector<LinesBucket>                                                           _buckets;
     std::priority_queue<LinesBucket *, std::vector<LinesBucket *>, LinesBucketPtrComp> _pq;
-    std::map<int, const void *>                                                        _idToObjsPtr;
-    std::map<const void *, int>                                                        _objsPtrToId;
 
 public:
-    void        emplace_back_bucket(std::vector<ExtrusionPaths> &&paths, const void *objPtr, Point offset);
+    void        emplace_back_bucket(ExtrusionLayers &&els, const void *objPtr, Point offset);
     bool        valid() const { return _pq.empty() == false; }
-    const void *idToObjsPtr(int id)
+    float       getCurrBottomZ();
-    {
-        if (_idToObjsPtr.find(id) != _idToObjsPtr.end())
-            return _idToObjsPtr[id];
-        else
-            return nullptr;
-    }
-    double      removeLowests();
     LineWithIDs getCurLines() const;
 };
 
 void getExtrusionPathsFromEntity(const ExtrusionEntityCollection *entity, ExtrusionPaths &paths);
 
-ExtrusionPaths getExtrusionPathsFromLayer(LayerRegionPtrs layerRegionPtrs);
+ExtrusionLayers getExtrusionPathsFromLayer(const LayerRegionPtrs layerRegionPtrs);
 
-ExtrusionPaths getExtrusionPathsFromSupportLayer(SupportLayer *supportLayer);
+ExtrusionLayer getExtrusionPathsFromSupportLayer(SupportLayer *supportLayer);
 
-std::pair<std::vector<ExtrusionPaths>, std::vector<ExtrusionPaths>> getAllLayersExtrusionPathsFromObject(PrintObject *obj);
+ObjectExtrusions getAllLayersExtrusionPathsFromObject(PrintObject *obj);
 
 struct ConflictComputeResult
 {
-    int _obj1;
+    const void* _obj1;
-    int _obj2;
+    const void* _obj2;
 
-    ConflictComputeResult(int o1, int o2) : _obj1(o1), _obj2(o2) {}
+    ConflictComputeResult(const void* o1, const void* o2) : _obj1(o1), _obj2(o2) {}
     ConflictComputeResult() = default;
 };
 

src/libslic3r/GCode/SpiralVase.cpp

@@ -54,7 +54,7 @@ std::string SpiralVase::process_layer(const std::string &gcode)
     // For absolute extruder distances it will be switched off.
     // Tapering the absolute extruder distances requires to process every extrusion value after the first transition
     // layer.
-    bool  transition = m_transition_layer && m_config.use_relative_e_distances;
+    bool  transition = m_transition_layer && m_config.use_relative_e_distances.value;
     float layer_height_factor = layer_height / total_layer_length;
     float len = 0.f;
     m_reader.parse_buffer(gcode, [&new_gcode, &z, total_layer_length, layer_height_factor, transition, &len]

src/libslic3r/Geometry/VoronoiOffset.cpp

@@ -782,6 +782,9 @@ void annotate_inside_outside(VD &vd, const Lines &lines)
 
     for (const VD::edge_type &edge : vd.edges())
         if (edge.vertex1() == nullptr) {
+            if (edge.vertex0() == nullptr)
+                continue;
+
             // Infinite Voronoi edge separating two Point sites or a Point site and a Segment site.
             // Infinite edge is always outside and it references at least one valid vertex.
             assert(edge.is_infinite());
@@ -888,6 +891,9 @@ void annotate_inside_outside(VD &vd, const Lines &lines)
     for (const VD::edge_type &edge : vd.edges()) {
         assert((edge_category(edge) == EdgeCategory::Unknown) == (edge_category(edge.twin()) == EdgeCategory::Unknown));
         if (edge_category(edge) == EdgeCategory::Unknown) {
+            if (!edge.is_finite())
+                continue;
+
             assert(edge.is_finite());
             const VD::cell_type &cell   = *edge.cell();
             const VD::cell_type &cell2  = *edge.twin()->cell();

src/libslic3r/MeshBoolean.cpp

@@ -2,6 +2,7 @@
 #include "MeshBoolean.hpp"
 #include "libslic3r/TriangleMesh.hpp"
 #include "libslic3r/TryCatchSignal.hpp"
+#include "libslic3r/format.hpp"
 #undef PI
 
 // Include igl first. It defines "L" macro which then clashes with our localization
@@ -12,6 +13,7 @@
 #include <CGAL/Polygon_mesh_processing/corefinement.h>
 #include <CGAL/Exact_integer.h>
 #include <CGAL/Surface_mesh.h>
+#include <CGAL/Cartesian_converter.h>
 #include <CGAL/Polygon_mesh_processing/orient_polygon_soup.h>
 #include <CGAL/Polygon_mesh_processing/repair.h>
 #include <CGAL/Polygon_mesh_processing/remesh.h>
@@ -22,6 +24,9 @@
 #include <CGAL/property_map.h>
 #include <CGAL/boost/graph/copy_face_graph.h>
 #include <CGAL/boost/graph/Face_filtered_graph.h>
+// BBS: for boolean using mcut
+#include "mcut/include/mcut/mcut.h"
+#include "boost/log/trivial.hpp"
 
 namespace Slic3r {
 namespace MeshBoolean {
@@ -32,17 +37,17 @@ using MapMatrixXiUnaligned = Eigen::Map<const Eigen::Matrix<int,   Eigen::Dynami
 TriangleMesh eigen_to_triangle_mesh(const EigenMesh &emesh)
 {
     auto &VC = emesh.first; auto &FC = emesh.second;
-    
+
     indexed_triangle_set its;
     its.vertices.reserve(size_t(VC.rows()));
     its.indices.reserve(size_t(FC.rows()));
-    
+
     for (Eigen::Index i = 0; i < VC.rows(); ++i)
         its.vertices.emplace_back(VC.row(i).cast<float>());
-    
+
     for (Eigen::Index i = 0; i < FC.rows(); ++i)
         its.indices.emplace_back(FC.row(i));
-    
+
     return TriangleMesh { std::move(its) };
 }
 
@@ -63,12 +68,12 @@ void minus(EigenMesh &A, const EigenMesh &B)
 {
     auto &[VA, FA] = A;
     auto &[VB, FB] = B;
-    
+
     Eigen::MatrixXd VC;
     Eigen::MatrixXi FC;
     igl::MeshBooleanType boolean_type(igl::MESH_BOOLEAN_TYPE_MINUS);
     igl::copyleft::cgal::mesh_boolean(VA, FA, VB, FB, boolean_type, VC, FC);
-    
+
     VA = std::move(VC); FA = std::move(FC);
 }
 
@@ -87,7 +92,7 @@ void self_union(EigenMesh &A)
 
     igl::MeshBooleanType boolean_type(igl::MESH_BOOLEAN_TYPE_UNION);
     igl::copyleft::cgal::mesh_boolean(V, F, Eigen::MatrixXd(), Eigen::MatrixXi(), boolean_type, VC, FC);
-    
+
     A = std::move(result);
 }
 
@@ -114,6 +119,11 @@ struct CGALMesh {
     CGALMesh(const _EpicMesh& _m) :m(_m) {}
 };
 
+void save_CGALMesh(const std::string& fname, const CGALMesh& cgal_mesh) {
+    std::ofstream os(fname);
+    os << cgal_mesh.m;
+    os.close();
+}
 // /////////////////////////////////////////////////////////////////////////////
 // Converions from and to CGAL mesh
 // /////////////////////////////////////////////////////////////////////////////
@@ -179,12 +189,13 @@ inline Vec3f to_vec3f(const _EpecMesh::Point& v)
     return { float(iv.x()), float(iv.y()), float(iv.z()) };
 }
 
-template<class _Mesh> TriangleMesh cgal_to_triangle_mesh(const _Mesh &cgalmesh)
+template<class _Mesh>
+indexed_triangle_set cgal_to_indexed_triangle_set(const _Mesh &cgalmesh)
 {
     indexed_triangle_set its;
     its.vertices.reserve(cgalmesh.num_vertices());
     its.indices.reserve(cgalmesh.num_faces());
-    
+
     const auto &faces = cgalmesh.faces();
     const auto &vertices = cgalmesh.vertices();
     int vsize = int(vertices.size());
@@ -208,8 +219,8 @@ template<class _Mesh> TriangleMesh cgal_to_triangle_mesh(const _Mesh &cgalmesh)
         if (i == 3)
             its.indices.emplace_back(facet);
     }
-    
+
-    return TriangleMesh(std::move(its));
+    return its;
 }
 
 std::unique_ptr<CGALMesh, CGALMeshDeleter>
@@ -223,7 +234,12 @@ triangle_mesh_to_cgal(const std::vector<stl_vertex> &V,
 
 TriangleMesh cgal_to_triangle_mesh(const CGALMesh &cgalmesh)
 {
-    return cgal_to_triangle_mesh(cgalmesh.m);
+    return TriangleMesh{cgal_to_indexed_triangle_set(cgalmesh.m)};
+}
+
+indexed_triangle_set cgal_to_indexed_triangle_set(const CGALMesh &cgalmesh)
+{
+    return cgal_to_indexed_triangle_set(cgalmesh.m);
 }
 
 // /////////////////////////////////////////////////////////////////////////////
@@ -303,10 +319,7 @@ void segment(CGALMesh& src, std::vector<CGALMesh>& dst, double smoothing_alpha =
         _EpicMesh out;
         CGAL::copy_face_graph(segment_mesh, out);
 
-        //std::ostringstream oss;
+        // save_CGALMesh("out.off", out);
-        //oss << "Segment_" << id << ".off";
-        //std::ofstream os(oss.str().data());
-        //os << out;
 
         // fill holes
         typedef boost::graph_traits<_EpicMesh>::halfedge_descriptor      halfedge_descriptor;
@@ -330,7 +343,7 @@ void segment(CGALMesh& src, std::vector<CGALMesh>& dst, double smoothing_alpha =
         //if (id > 2) {
         //    mesh_merged.join(out);
         //}
-        //else 
+        //else
         {
             dst.emplace_back(std::move(CGALMesh(out)));
         }
@@ -382,9 +395,17 @@ TriangleMesh merge(std::vector<TriangleMesh> meshes)
     return cgal_to_triangle_mesh(dst);
 }
 
-// /////////////////////////////////////////////////////////////////////////////
+template<class Op> void _mesh_boolean_do(Op &&op, indexed_triangle_set &A, const indexed_triangle_set &B)
-// Now the public functions for TriangleMesh input:
+{
-// /////////////////////////////////////////////////////////////////////////////
+    CGALMesh meshA;
+    CGALMesh meshB;
+    triangle_mesh_to_cgal(A.vertices, A.indices, meshA.m);
+    triangle_mesh_to_cgal(B.vertices, B.indices, meshB.m);
+
+    _cgal_do(op, meshA, meshB);
+
+    A = cgal_to_indexed_triangle_set(meshA.m);
+}
 
 template<class Op> void _mesh_boolean_do(Op &&op, TriangleMesh &A, const TriangleMesh &B)
 {
@@ -392,10 +413,10 @@ template<class Op> void _mesh_boolean_do(Op &&op, TriangleMesh &A, const Triangl
     CGALMesh meshB;
     triangle_mesh_to_cgal(A.its.vertices, A.its.indices, meshA.m);
     triangle_mesh_to_cgal(B.its.vertices, B.its.indices, meshB.m);
-    
+
     _cgal_do(op, meshA, meshB);
-    
+
-    A = cgal_to_triangle_mesh(meshA.m);
+    A = cgal_to_triangle_mesh(meshA);
 }
 
 void minus(TriangleMesh &A, const TriangleMesh &B)
@@ -413,6 +434,21 @@ void intersect(TriangleMesh &A, const TriangleMesh &B)
     _mesh_boolean_do(_cgal_intersection, A, B);
 }
 
+void minus(indexed_triangle_set &A, const indexed_triangle_set &B)
+{
+    _mesh_boolean_do(_cgal_diff, A, B);
+}
+
+void plus(indexed_triangle_set &A, const indexed_triangle_set &B)
+{
+    _mesh_boolean_do(_cgal_union, A, B);
+}
+
+void intersect(indexed_triangle_set &A, const indexed_triangle_set &B)
+{
+    _mesh_boolean_do(_cgal_intersection, A, B);
+}
+
 bool does_self_intersect(const TriangleMesh &mesh)
 {
     CGALMesh cgalm;
@@ -424,7 +460,7 @@ void CGALMeshDeleter::operator()(CGALMesh *ptr) { delete ptr; }
 
 bool does_bound_a_volume(const CGALMesh &mesh)
 {
-    return CGALProc::does_bound_a_volume(mesh.m);
+    return CGAL::is_closed(mesh.m) && CGALProc::does_bound_a_volume(mesh.m);
 }
 
 bool empty(const CGALMesh &mesh)
@@ -432,7 +468,437 @@ bool empty(const CGALMesh &mesh)
     return mesh.m.is_empty();
 }
 
+CGALMeshPtr clone(const CGALMesh &m)
+{
+    return CGALMeshPtr{new CGALMesh{m}};
+}
+
 } // namespace cgal
 
+
+namespace mcut {
+/* BBS: MusangKing
+ * mcut mesh array format for Boolean Opts calculation
+ */
+struct McutMesh
+{
+    // variables for mesh data in a format suited for mcut
+    std::vector<uint32_t> faceSizesArray;
+    std::vector<uint32_t> faceIndicesArray;
+    std::vector<double>   vertexCoordsArray;
+};
+void McutMeshDeleter::operator()(McutMesh *ptr) { delete ptr; }
+
+bool empty(const McutMesh &mesh) { return mesh.vertexCoordsArray.empty() || mesh.faceIndicesArray.empty(); }
+void triangle_mesh_to_mcut(const TriangleMesh &src_mesh, McutMesh &srcMesh, const Transform3d &src_nm = Transform3d::Identity())
+{
+    // vertices precision convention and copy
+    srcMesh.vertexCoordsArray.reserve(src_mesh.its.vertices.size() * 3);
+    for (int i = 0; i < src_mesh.its.vertices.size(); ++i) {
+        const Vec3d v = src_nm * src_mesh.its.vertices[i].cast<double>();
+        srcMesh.vertexCoordsArray.push_back(v[0]);
+        srcMesh.vertexCoordsArray.push_back(v[1]);
+        srcMesh.vertexCoordsArray.push_back(v[2]);
+    }
+
+    // faces copy
+    srcMesh.faceIndicesArray.reserve(src_mesh.its.indices.size() * 3);
+    srcMesh.faceSizesArray.reserve(src_mesh.its.indices.size());
+    for (int i = 0; i < src_mesh.its.indices.size(); ++i) {
+        const int &f0 = src_mesh.its.indices[i][0];
+        const int &f1 = src_mesh.its.indices[i][1];
+        const int &f2 = src_mesh.its.indices[i][2];
+        srcMesh.faceIndicesArray.push_back(f0);
+        srcMesh.faceIndicesArray.push_back(f1);
+        srcMesh.faceIndicesArray.push_back(f2);
+
+        srcMesh.faceSizesArray.push_back((uint32_t) 3);
+    }
+}
+
+McutMeshPtr triangle_mesh_to_mcut(const indexed_triangle_set &M)
+{
+    std::unique_ptr<McutMesh, McutMeshDeleter> out(new McutMesh{});
+    TriangleMesh                               trimesh(M);
+    triangle_mesh_to_mcut(trimesh, *out.get());
+    return out;
+}
+
+TriangleMesh mcut_to_triangle_mesh(const McutMesh &mcutmesh)
+{
+    uint32_t ccVertexCount = mcutmesh.vertexCoordsArray.size() / 3;
+    auto    &ccVertices    = mcutmesh.vertexCoordsArray;
+    auto    &ccFaceIndices = mcutmesh.faceIndicesArray;
+    auto    &faceSizes     = mcutmesh.faceSizesArray;
+    uint32_t ccFaceCount   = faceSizes.size();
+    // rearrange vertices/faces and save into result mesh
+    std::vector<Vec3f> vertices(ccVertexCount);
+    for (uint32_t i = 0; i < ccVertexCount; i++) {
+        vertices[i][0] = (float) ccVertices[(uint64_t) i * 3 + 0];
+        vertices[i][1] = (float) ccVertices[(uint64_t) i * 3 + 1];
+        vertices[i][2] = (float) ccVertices[(uint64_t) i * 3 + 2];
+    }
+
+    // output faces
+    int faceVertexOffsetBase = 0;
+
+    // for each face in CC
+    std::vector<Vec3i> faces(ccFaceCount);
+    for (uint32_t f = 0; f < ccFaceCount; ++f) {
+        int faceSize = faceSizes.at(f);
+
+        // for each vertex in face
+        for (int v = 0; v < faceSize; v++) { faces[f][v] = ccFaceIndices[(uint64_t) faceVertexOffsetBase + v]; }
+        faceVertexOffsetBase += faceSize;
+    }
+
+    TriangleMesh out(vertices, faces);
+    return out;
+}
+
+void merge_mcut_meshes(McutMesh& src, const McutMesh& cut) {
+    indexed_triangle_set all_its;
+    TriangleMesh tri_src = mcut_to_triangle_mesh(src);
+    TriangleMesh tri_cut = mcut_to_triangle_mesh(cut);
+    its_merge(all_its, tri_src.its);
+    its_merge(all_its, tri_cut.its);
+    src = *triangle_mesh_to_mcut(all_its);
+    }
+
+MCAPI_ATTR void MCAPI_CALL mcDebugOutput(McDebugSource source,
+    McDebugType type,
+    unsigned int id,
+    McDebugSeverity severity,
+    size_t length,
+    const char* message,
+    const void* userParam)
+{
+    BOOST_LOG_TRIVIAL(debug)<<Slic3r::format("mcut mcDebugOutput message ( %d ): %s ", id, message);
+
+    switch (source) {
+        case MC_DEBUG_SOURCE_API:
+            BOOST_LOG_TRIVIAL(debug)<<("Source: API");
+            break;
+        case MC_DEBUG_SOURCE_KERNEL:
+            BOOST_LOG_TRIVIAL(debug)<<("Source: Kernel");
+            break;
+        }
+
+    switch (type) {
+        case MC_DEBUG_TYPE_ERROR:
+            BOOST_LOG_TRIVIAL(debug)<<("Type: Error");
+            break;
+        case MC_DEBUG_TYPE_DEPRECATED_BEHAVIOR:
+            BOOST_LOG_TRIVIAL(debug)<<("Type: Deprecated Behaviour");
+            break;
+        case MC_DEBUG_TYPE_OTHER:
+            BOOST_LOG_TRIVIAL(debug)<<("Type: Other");
+            break;
+        }
+
+    switch (severity) {
+        case MC_DEBUG_SEVERITY_HIGH:
+            BOOST_LOG_TRIVIAL(debug)<<("Severity: high");
+            break;
+        case MC_DEBUG_SEVERITY_MEDIUM:
+            BOOST_LOG_TRIVIAL(debug)<<("Severity: medium");
+            break;
+        case MC_DEBUG_SEVERITY_LOW:
+            BOOST_LOG_TRIVIAL(debug)<<("Severity: low");
+            break;
+        case MC_DEBUG_SEVERITY_NOTIFICATION:
+            BOOST_LOG_TRIVIAL(debug)<<("Severity: notification");
+            break;
+        }
+}
+
+
+void do_boolean(McutMesh &srcMesh, const McutMesh &cutMesh, const std::string &boolean_opts)
+{
+    // create context
+    McContext context = MC_NULL_HANDLE;
+    McResult  err     = mcCreateContext(&context, 0);
+    // add debug callback according to https://cutdigital.github.io/mcut.site/tutorials/debugging/
+    mcDebugMessageCallback(context, mcDebugOutput, nullptr);
+    mcDebugMessageControl(
+        context,
+        MC_DEBUG_SOURCE_ALL,
+        MC_DEBUG_TYPE_ERROR,
+        MC_DEBUG_SEVERITY_MEDIUM,
+        true);
+    // We can either let MCUT compute all possible meshes (including patches etc.), or we can
+    // constrain the library to compute exactly the boolean op mesh we want. This 'constrained' case
+    // is done with the following flags.
+    // NOTE#1: you can extend these flags by bitwise ORing with additional flags (see `McDispatchFlags' in mcut.h)
+    // NOTE#2: below order of columns MATTERS
+    const std::map<std::string, McFlags> booleanOpts = {
+        {"A_NOT_B", MC_DISPATCH_FILTER_FRAGMENT_SEALING_INSIDE | MC_DISPATCH_FILTER_FRAGMENT_LOCATION_ABOVE},
+        {"B_NOT_A", MC_DISPATCH_FILTER_FRAGMENT_SEALING_OUTSIDE | MC_DISPATCH_FILTER_FRAGMENT_LOCATION_BELOW},
+        {"UNION", MC_DISPATCH_FILTER_FRAGMENT_SEALING_OUTSIDE | MC_DISPATCH_FILTER_FRAGMENT_LOCATION_ABOVE},
+        {"INTERSECTION", MC_DISPATCH_FILTER_FRAGMENT_SEALING_INSIDE | MC_DISPATCH_FILTER_FRAGMENT_LOCATION_BELOW},
+    };
+
+    std::map<std::string, McFlags>::const_iterator it          = booleanOpts.find(boolean_opts);
+    McFlags                                        boolOpFlags = it->second;
+
+    if (srcMesh.vertexCoordsArray.empty() && (boolean_opts == "UNION" || boolean_opts == "B_NOT_A")) {
+        srcMesh = cutMesh;
+        mcReleaseContext(context);
+        return;
+    }
+
+    err = mcDispatch(context,
+                     MC_DISPATCH_VERTEX_ARRAY_DOUBLE |          // vertices are in array of doubles
+                         MC_DISPATCH_ENFORCE_GENERAL_POSITION | // perturb if necessary
+                         boolOpFlags,                           // filter flags which specify the type of output we want
+                     // source mesh
+                     reinterpret_cast<const void *>(srcMesh.vertexCoordsArray.data()), reinterpret_cast<const uint32_t *>(srcMesh.faceIndicesArray.data()),
+                     srcMesh.faceSizesArray.data(), static_cast<uint32_t>(srcMesh.vertexCoordsArray.size() / 3), static_cast<uint32_t>(srcMesh.faceSizesArray.size()),
+                     // cut mesh
+                     reinterpret_cast<const void *>(cutMesh.vertexCoordsArray.data()), cutMesh.faceIndicesArray.data(), cutMesh.faceSizesArray.data(),
+                     static_cast<uint32_t>(cutMesh.vertexCoordsArray.size() / 3), static_cast<uint32_t>(cutMesh.faceSizesArray.size()));
+    if (err != MC_NO_ERROR) {
+        BOOST_LOG_TRIVIAL(debug) << "MCUT mcDispatch fails! err=" << err;
+        mcReleaseContext(context);
+        if (boolean_opts == "UNION") {
+            merge_mcut_meshes(srcMesh, cutMesh);
+        }
+        else {
+            // when src mesh has multiple connected components, mcut refuses to work.
+            // But we can force it to work by spliting the src mesh into disconnected components,
+            // and do booleans seperately, then merge all the results.
+            indexed_triangle_set all_its;
+            TriangleMesh tri_src = mcut_to_triangle_mesh(srcMesh);
+            std::vector<indexed_triangle_set> src_parts = its_split(tri_src.its);
+            if (src_parts.size() == 1)
+            {
+                //can not split, return error directly
+                BOOST_LOG_TRIVIAL(error) << boost::format("bool operation %1% failed, also can not split")%boolean_opts;
+                return;
+            }
+            for (size_t i = 0; i < src_parts.size(); i++)
+            {
+                auto part = triangle_mesh_to_mcut(src_parts[i]);
+                do_boolean(*part, cutMesh, boolean_opts);
+                TriangleMesh tri_part = mcut_to_triangle_mesh(*part);
+                its_merge(all_its, tri_part.its);
+            }
+            srcMesh = *triangle_mesh_to_mcut(all_its);
+        }
+
+        return;
+    }
+
+    // query the number of available connected component
+    uint32_t numConnComps;
+    err = mcGetConnectedComponents(context, MC_CONNECTED_COMPONENT_TYPE_FRAGMENT, 0, NULL, &numConnComps);
+    if (err != MC_NO_ERROR || numConnComps==0) {
+        BOOST_LOG_TRIVIAL(debug) << "MCUT mcGetConnectedComponents fails! err=" << err << ", numConnComps" << numConnComps;
+        mcReleaseContext(context);
+        if (numConnComps == 0 && boolean_opts == "UNION") {
+            merge_mcut_meshes(srcMesh, cutMesh);
+        }
+        return;
+    }
+
+    std::vector<McConnectedComponent> connectedComponents(numConnComps, MC_NULL_HANDLE);
+    err = mcGetConnectedComponents(context, MC_CONNECTED_COMPONENT_TYPE_FRAGMENT, (uint32_t) connectedComponents.size(), connectedComponents.data(), NULL);
+
+    McutMesh outMesh;
+    int N_vertices = 0;
+    // traversal of all connected components
+    for (int n = 0; n < numConnComps; ++n) {
+        // query the data of each connected component from MCUT
+        McConnectedComponent connComp = connectedComponents[n];
+
+        // query the vertices
+        McSize numBytes                  = 0;
+        err                               = mcGetConnectedComponentData(context, connComp, MC_CONNECTED_COMPONENT_DATA_VERTEX_DOUBLE, 0, NULL, &numBytes);
+        uint32_t            ccVertexCount = (uint32_t) (numBytes / (sizeof(double) * 3));
+        std::vector<double> ccVertices((uint64_t) ccVertexCount * 3u, 0);
+        err = mcGetConnectedComponentData(context, connComp, MC_CONNECTED_COMPONENT_DATA_VERTEX_DOUBLE, numBytes, (void *) ccVertices.data(), NULL);
+
+        // query the faces
+        numBytes = 0;
+        err      = mcGetConnectedComponentData(context, connComp, MC_CONNECTED_COMPONENT_DATA_FACE_TRIANGULATION, 0, NULL, &numBytes);
+        std::vector<uint32_t> ccFaceIndices(numBytes / sizeof(uint32_t), 0);
+        err = mcGetConnectedComponentData(context, connComp, MC_CONNECTED_COMPONENT_DATA_FACE_TRIANGULATION, numBytes, ccFaceIndices.data(), NULL);
+        std::vector<uint32_t> faceSizes(ccFaceIndices.size() / 3, 3);
+
+        const uint32_t ccFaceCount = static_cast<uint32_t>(faceSizes.size());
+
+        // Here we show, how to know when connected components, pertain particular boolean operations.
+        McPatchLocation patchLocation = (McPatchLocation) 0;
+        err                           = mcGetConnectedComponentData(context, connComp, MC_CONNECTED_COMPONENT_DATA_PATCH_LOCATION, sizeof(McPatchLocation), &patchLocation, NULL);
+
+        McFragmentLocation fragmentLocation = (McFragmentLocation) 0;
+        err = mcGetConnectedComponentData(context, connComp, MC_CONNECTED_COMPONENT_DATA_FRAGMENT_LOCATION, sizeof(McFragmentLocation), &fragmentLocation, NULL);
+
+        outMesh.vertexCoordsArray.insert(outMesh.vertexCoordsArray.end(), ccVertices.begin(), ccVertices.end());
+
+        // add offset to face index
+        for (size_t i = 0; i < ccFaceIndices.size(); i++) {
+            ccFaceIndices[i] += N_vertices;
+        }
+
+        int faceVertexOffsetBase = 0;
+
+        // for each face in CC
+        std::vector<Vec3i> faces(ccFaceCount);
+        for (uint32_t f = 0; f < ccFaceCount; ++f) {
+            bool reverseWindingOrder = (fragmentLocation == MC_FRAGMENT_LOCATION_BELOW) && (patchLocation == MC_PATCH_LOCATION_OUTSIDE);
+            int  faceSize            = faceSizes.at(f);
+            if (reverseWindingOrder) {
+                std::vector<uint32_t> faceIndex(faceSize);
+                // for each vertex in face
+                for (int v = faceSize - 1; v >= 0; v--) { faceIndex[v] = ccFaceIndices[(uint64_t) faceVertexOffsetBase + v]; }
+                std::copy(faceIndex.begin(), faceIndex.end(), ccFaceIndices.begin() + faceVertexOffsetBase);
+            }
+            faceVertexOffsetBase += faceSize;
+        }
+
+        outMesh.faceIndicesArray.insert(outMesh.faceIndicesArray.end(), ccFaceIndices.begin(), ccFaceIndices.end());
+        outMesh.faceSizesArray.insert(outMesh.faceSizesArray.end(), faceSizes.begin(), faceSizes.end());
+
+        N_vertices += ccVertexCount;
+    }
+
+    // free connected component data
+    err = mcReleaseConnectedComponents(context, 0, NULL);
+
+    // destroy context
+    err = mcReleaseContext(context);
+
+    srcMesh = outMesh;
+}
+
+/* BBS: Musang King
+ * mcut for Mesh Boolean which provides C-style syntax API
+ */
+std::vector<TriangleMesh> make_boolean(const McutMesh &srcMesh, const McutMesh &cutMesh, const std::string &boolean_opts)
+{
+    // create context
+    McContext context = MC_NULL_HANDLE;
+    McResult  err     = mcCreateContext(&context, 0);
+    // add debug callback according to https://cutdigital.github.io/mcut.site/tutorials/debugging/
+    mcDebugMessageCallback(context, mcDebugOutput, nullptr);
+    mcDebugMessageControl(
+        context,
+        MC_DEBUG_SOURCE_ALL,
+        MC_DEBUG_TYPE_ERROR,
+        MC_DEBUG_SEVERITY_MEDIUM,
+        true);
+    // We can either let MCUT compute all possible meshes (including patches etc.), or we can
+    // constrain the library to compute exactly the boolean op mesh we want. This 'constrained' case
+    // is done with the following flags.
+    // NOTE#1: you can extend these flags by bitwise ORing with additional flags (see `McDispatchFlags' in mcut.h)
+    // NOTE#2: below order of columns MATTERS
+    const std::map<std::string, McFlags> booleanOpts = {
+        {"A_NOT_B", MC_DISPATCH_FILTER_FRAGMENT_SEALING_INSIDE | MC_DISPATCH_FILTER_FRAGMENT_LOCATION_ABOVE},
+        {"B_NOT_A", MC_DISPATCH_FILTER_FRAGMENT_SEALING_OUTSIDE | MC_DISPATCH_FILTER_FRAGMENT_LOCATION_BELOW},
+        {"UNION", MC_DISPATCH_FILTER_FRAGMENT_SEALING_OUTSIDE | MC_DISPATCH_FILTER_FRAGMENT_LOCATION_ABOVE},
+        {"INTERSECTION", MC_DISPATCH_FILTER_FRAGMENT_SEALING_INSIDE | MC_DISPATCH_FILTER_FRAGMENT_LOCATION_BELOW},
+    };
+
+    std::map<std::string, McFlags>::const_iterator it          = booleanOpts.find(boolean_opts);
+    McFlags                                        boolOpFlags = it->second;
+
+    err = mcDispatch(context,
+                     MC_DISPATCH_VERTEX_ARRAY_DOUBLE |          // vertices are in array of doubles
+                         MC_DISPATCH_ENFORCE_GENERAL_POSITION | // perturb if necessary
+                         boolOpFlags,                           // filter flags which specify the type of output we want
+                     // source mesh
+                     reinterpret_cast<const void *>(srcMesh.vertexCoordsArray.data()), reinterpret_cast<const uint32_t *>(srcMesh.faceIndicesArray.data()),
+                     srcMesh.faceSizesArray.data(), static_cast<uint32_t>(srcMesh.vertexCoordsArray.size() / 3), static_cast<uint32_t>(srcMesh.faceSizesArray.size()),
+                     // cut mesh
+                     reinterpret_cast<const void *>(cutMesh.vertexCoordsArray.data()), cutMesh.faceIndicesArray.data(), cutMesh.faceSizesArray.data(),
+                     static_cast<uint32_t>(cutMesh.vertexCoordsArray.size() / 3), static_cast<uint32_t>(cutMesh.faceSizesArray.size()));
+
+    // query the number of available connected component
+    uint32_t numConnComps;
+    err = mcGetConnectedComponents(context, MC_CONNECTED_COMPONENT_TYPE_FRAGMENT, 0, NULL, &numConnComps);
+
+    std::vector<McConnectedComponent> connectedComponents(numConnComps, MC_NULL_HANDLE);
+    err = mcGetConnectedComponents(context, MC_CONNECTED_COMPONENT_TYPE_FRAGMENT, (uint32_t) connectedComponents.size(), connectedComponents.data(), NULL);
+
+    std::vector<TriangleMesh> outs;
+    // traversal of all connected components
+    for (int n = 0; n < numConnComps; ++n) {
+        // query the data of each connected component from MCUT
+        McConnectedComponent connComp = connectedComponents[n];
+
+        // query the vertices
+        McSize numBytes                   = 0;
+        err                               = mcGetConnectedComponentData(context, connComp, MC_CONNECTED_COMPONENT_DATA_VERTEX_DOUBLE, 0, NULL, &numBytes);
+        uint32_t            ccVertexCount = (uint32_t) (numBytes / (sizeof(double) * 3));
+        std::vector<double> ccVertices((uint64_t) ccVertexCount * 3u, 0);
+        err = mcGetConnectedComponentData(context, connComp, MC_CONNECTED_COMPONENT_DATA_VERTEX_DOUBLE, numBytes, (void *) ccVertices.data(), NULL);
+
+        // query the faces
+        numBytes = 0;
+        err      = mcGetConnectedComponentData(context, connComp, MC_CONNECTED_COMPONENT_DATA_FACE_TRIANGULATION, 0, NULL, &numBytes);
+        std::vector<uint32_t> ccFaceIndices(numBytes / sizeof(uint32_t), 0);
+        err = mcGetConnectedComponentData(context, connComp, MC_CONNECTED_COMPONENT_DATA_FACE_TRIANGULATION, numBytes, ccFaceIndices.data(), NULL);
+        std::vector<uint32_t> faceSizes(ccFaceIndices.size() / 3, 3);
+
+        const uint32_t ccFaceCount = static_cast<uint32_t>(faceSizes.size());
+
+        // Here we show, how to know when connected components, pertain particular boolean operations.
+        McPatchLocation patchLocation = (McPatchLocation) 0;
+        err                           = mcGetConnectedComponentData(context, connComp, MC_CONNECTED_COMPONENT_DATA_PATCH_LOCATION, sizeof(McPatchLocation), &patchLocation, NULL);
+
+        McFragmentLocation fragmentLocation = (McFragmentLocation) 0;
+        err = mcGetConnectedComponentData(context, connComp, MC_CONNECTED_COMPONENT_DATA_FRAGMENT_LOCATION, sizeof(McFragmentLocation), &fragmentLocation, NULL);
+
+        // rearrange vertices/faces and save into result mesh
+        std::vector<Vec3f> vertices(ccVertexCount);
+        for (uint32_t i = 0; i < ccVertexCount; ++i) {
+            vertices[i][0] = (float) ccVertices[(uint64_t) i * 3 + 0];
+            vertices[i][1] = (float) ccVertices[(uint64_t) i * 3 + 1];
+            vertices[i][2] = (float) ccVertices[(uint64_t) i * 3 + 2];
+        }
+
+        // output faces
+        int faceVertexOffsetBase = 0;
+
+        // for each face in CC
+        std::vector<Vec3i> faces(ccFaceCount);
+        for (uint32_t f = 0; f < ccFaceCount; ++f) {
+            bool reverseWindingOrder = (fragmentLocation == MC_FRAGMENT_LOCATION_BELOW) && (patchLocation == MC_PATCH_LOCATION_OUTSIDE);
+            int  faceSize            = faceSizes.at(f);
+
+            // for each vertex in face
+            for (int v = (reverseWindingOrder ? (faceSize - 1) : 0); (reverseWindingOrder ? (v >= 0) : (v < faceSize)); v += (reverseWindingOrder ? -1 : 1)) {
+                faces[f][v] = ccFaceIndices[(uint64_t) faceVertexOffsetBase + v];
+            }
+            faceVertexOffsetBase += faceSize;
+        }
+
+        TriangleMesh out(vertices, faces);
+        outs.emplace_back(out);
+    }
+
+    // free connected component data
+    err = mcReleaseConnectedComponents(context, (uint32_t) connectedComponents.size(), connectedComponents.data());
+
+    // destroy context
+    err = mcReleaseContext(context);
+
+    return outs;
+}
+
+void make_boolean(const TriangleMesh &src_mesh, const TriangleMesh &cut_mesh, std::vector<TriangleMesh> &dst_mesh, const std::string &boolean_opts)
+{
+    McutMesh srcMesh, cutMesh;
+    triangle_mesh_to_mcut(src_mesh, srcMesh);
+    triangle_mesh_to_mcut(cut_mesh, cutMesh);
+    //dst_mesh = make_boolean(srcMesh, cutMesh, boolean_opts);
+    do_boolean(srcMesh, cutMesh, boolean_opts);
+    dst_mesh.push_back(mcut_to_triangle_mesh(srcMesh));
+}
+
+} // namespace mcut
+
+
 } // namespace MeshBoolean
 } // namespace Slic3r

src/libslic3r/MeshBoolean.hpp

@@ -26,27 +26,37 @@ namespace cgal {
 
 struct CGALMesh;
 struct CGALMeshDeleter { void operator()(CGALMesh *ptr); };
+using CGALMeshPtr = std::unique_ptr<CGALMesh, CGALMeshDeleter>;
 
-std::unique_ptr<CGALMesh, CGALMeshDeleter>
+CGALMeshPtr clone(const CGALMesh &m);
-triangle_mesh_to_cgal(const std::vector<stl_vertex> &V,
-                      const std::vector<stl_triangle_vertex_indices> &F);
 
-inline std::unique_ptr<CGALMesh, CGALMeshDeleter> triangle_mesh_to_cgal(const indexed_triangle_set &M)
+void save_CGALMesh(const std::string& fname, const CGALMesh& cgal_mesh);
+
+CGALMeshPtr triangle_mesh_to_cgal(
+    const std::vector<stl_vertex> &V,
+    const std::vector<stl_triangle_vertex_indices> &F);
+
+inline CGALMeshPtr triangle_mesh_to_cgal(const indexed_triangle_set &M)
 {
     return triangle_mesh_to_cgal(M.vertices, M.indices);
 }
-inline std::unique_ptr<CGALMesh, CGALMeshDeleter> triangle_mesh_to_cgal(const TriangleMesh &M)
+inline CGALMeshPtr triangle_mesh_to_cgal(const TriangleMesh &M)
 {
     return triangle_mesh_to_cgal(M.its);
 }
 
 TriangleMesh cgal_to_triangle_mesh(const CGALMesh &cgalmesh);
-    
+indexed_triangle_set cgal_to_indexed_triangle_set(const CGALMesh &cgalmesh);
+
 // Do boolean mesh difference with CGAL bypassing igl.
 void minus(TriangleMesh &A, const TriangleMesh &B);
 void plus(TriangleMesh &A, const TriangleMesh &B);
 void intersect(TriangleMesh &A, const TriangleMesh &B);
 
+void minus(indexed_triangle_set &A, const indexed_triangle_set &B);
+void plus(indexed_triangle_set &A, const indexed_triangle_set &B);
+void intersect(indexed_triangle_set &A, const indexed_triangle_set &B);
+
 void minus(CGALMesh &A, CGALMesh &B);
 void plus(CGALMesh &A, CGALMesh &B);
 void intersect(CGALMesh &A, CGALMesh &B);
@@ -62,6 +72,27 @@ bool does_bound_a_volume(const CGALMesh &mesh);
 bool empty(const CGALMesh &mesh);
 }
 
+namespace mcut {
+struct McutMesh;
+struct McutMeshDeleter
+{
+    void operator()(McutMesh *ptr);
+};
+using McutMeshPtr = std::unique_ptr<McutMesh, McutMeshDeleter>;
+bool empty(const McutMesh &mesh);
+
+McutMeshPtr  triangle_mesh_to_mcut(const indexed_triangle_set &M);
+TriangleMesh mcut_to_triangle_mesh(const McutMesh &mcutmesh);
+
+// do boolean and save result to srcMesh
+void do_boolean(McutMesh &srcMesh, const McutMesh &cutMesh, const std::string &boolean_opts);
+
+std::vector<TriangleMesh> make_boolean(const McutMesh &srcMesh, const McutMesh &cutMesh, const std::string &boolean_opts);
+
+// do boolean and convert result to TriangleMesh
+void make_boolean(const TriangleMesh &src_mesh, const TriangleMesh &cut_mesh, std::vector<TriangleMesh> &dst_mesh, const std::string &boolean_opts);
+} // namespace mcut
+
 } // namespace MeshBoolean
 } // namespace Slic3r
 #endif // libslic3r_MeshBoolean_hpp_

src/libslic3r/MeshSplitImpl.hpp

@@ -108,6 +108,21 @@ template<class IndexT> struct ItsNeighborsWrapper
     const auto& get_index() const noexcept { return index_ref; }
 };
 
+// Can be used as the second argument to its_split to apply a functor on each
+// part, instead of collecting them into a container.
+template<class Fn>
+struct SplitOutputFn {
+
+    Fn fn;
+
+    SplitOutputFn(Fn f): fn{std::move(f)} {}
+
+    SplitOutputFn &operator *() { return *this; }
+    void           operator=(indexed_triangle_set &&its) { fn(std::move(its)); }
+    void           operator=(indexed_triangle_set &its) { fn(its); }
+    SplitOutputFn& operator++() { return *this; };
+};
+
 // Splits a mesh into multiple meshes when possible.
 template<class Its, class OutputIt>
 void its_split(const Its &m, OutputIt out_it)
@@ -155,7 +170,8 @@ void its_split(const Its &m, OutputIt out_it)
             mesh.indices.emplace_back(new_face);
         }
 
-        out_it = std::move(mesh);
+        *out_it = std::move(mesh);
+        ++out_it;
     }
 }
 

src/libslic3r/Model.cpp

@@ -190,7 +190,7 @@ Model Model::read_from_file(const std::string& input_file, DynamicPrintConfig* c
     else if (boost::algorithm::iends_with(input_file, ".stl"))
         result = load_stl(input_file.c_str(), &model, nullptr, stlFn);
     else if (boost::algorithm::iends_with(input_file, ".obj"))
-        result = load_obj(input_file.c_str(), &model);
+        result = load_obj(input_file.c_str(), &model, message);
     else if (boost::algorithm::iends_with(input_file, ".svg"))
         result = load_svg(input_file.c_str(), &model, message);
     //BBS: remove the old .amf.xml files
@@ -1063,6 +1063,28 @@ void ModelObject::assign_new_unique_ids_recursive()
 // BBS: production extension
 int ModelObject::get_backup_id() const { return m_model ? get_model()->get_object_backup_id(*this) : -1; }
 
+// BBS: Boolean Operations impl. - MusangKing
+bool ModelObject::make_boolean(ModelObject *cut_object, const std::string &boolean_opts)
+{
+    // merge meshes into single volume instead of multi-parts object
+    if (this->volumes.size() != 1) {
+        // we can't merge meshes if there's not just one volume
+        return false;
+    }
+    std::vector<TriangleMesh> new_meshes;
+
+    const TriangleMesh &cut_mesh = cut_object->mesh();
+    MeshBoolean::mcut::make_boolean(this->mesh(), cut_mesh, new_meshes, boolean_opts);
+
+    this->clear_volumes();
+    int i = 1;
+    for (TriangleMesh &mesh : new_meshes) {
+        ModelVolume *vol = this->add_volume(mesh);
+        vol->name        = this->name + "_" + std::to_string(i++);
+    }
+    return true;
+}
+
 ModelVolume* ModelObject::add_volume(const TriangleMesh &mesh)
 {
     ModelVolume* v = new ModelVolume(this, mesh);
@@ -1707,7 +1729,7 @@ void ModelObject::apply_cut_connectors(const std::string &name)
         // Transform the new modifier to be aligned inside the instance
         new_volume->set_transformation(translate_transform * connector.rotation_m * scale_transform);
 
-        new_volume->cut_info = {connector.attribs.type, connector.radius_tolerance, connector.height_tolerance};
+        new_volume->cut_info = {connector.attribs.type, connector.radius, connector.height, connector.radius_tolerance, connector.height_tolerance};
         new_volume->name     = name + "-" + std::to_string(++connector_id);
     }
     cut_id.increase_connectors_cnt(cut_connectors.size());
@@ -1982,6 +2004,16 @@ static void reset_instance_transformation(ModelObject* object, size_t src_instan
 
     for (size_t i = 0; i < object->instances.size(); ++i) {
         auto& obj_instance = object->instances[i];
+
+        Geometry::Transformation instance_transformation_copy = obj_instance->get_transformation();
+        instance_transformation_copy.set_offset(Vec3d(0, 0, 0));
+        if (object->volumes.size() == 1) {
+            instance_transformation_copy.set_offset(-object->volumes[0]->get_offset());
+        }
+
+        if (i == src_instance_idx && object->volumes.size() == 1)
+            invalidate_translations(object, obj_instance);
+
         const Vec3d offset = obj_instance->get_offset();
         const double rot_z = obj_instance->get_rotation().z();
 
@@ -2011,6 +2043,13 @@ static void reset_instance_transformation(ModelObject* object, size_t src_instan
         }
 
         obj_instance->set_rotation(rotation);
+
+        // update the assemble matrix
+        const Transform3d &assemble_matrix = obj_instance->get_assemble_transformation().get_matrix();
+        const Transform3d &instance_inverse_matrix = instance_transformation_copy.get_matrix().inverse();
+        Transform3d new_instance_inverse_matrix = instance_inverse_matrix * obj_instance->get_transformation().get_matrix(true).inverse();
+        Transform3d new_assemble_transform = assemble_matrix * new_instance_inverse_matrix;
+        obj_instance->set_assemble_from_transform(new_assemble_transform);
     }
 }
 
@@ -2090,16 +2129,12 @@ ModelObjectPtrs ModelObject::cut(size_t instance, std::array<Vec3d, 4> plane_poi
     }
     else {
         if (attributes.has(ModelObjectCutAttribute::KeepUpper) && upper->volumes.size() > 0) {
-            invalidate_translations(upper, instances[instance]);
-
             reset_instance_transformation(upper, instance, cut_matrix, attributes.has(ModelObjectCutAttribute::PlaceOnCutUpper),
                                           attributes.has(ModelObjectCutAttribute::FlipUpper), local_displace);
 
             res.push_back(upper);
         }
         if (attributes.has(ModelObjectCutAttribute::KeepLower) && lower->volumes.size() > 0) {
-            invalidate_translations(lower, instances[instance]);
-
             reset_instance_transformation(lower, instance, cut_matrix, attributes.has(ModelObjectCutAttribute::PlaceOnCutLower),
                                           attributes.has(ModelObjectCutAttribute::PlaceOnCutLower) ? true : attributes.has(ModelObjectCutAttribute::FlipLower));
 
@@ -2108,8 +2143,6 @@ ModelObjectPtrs ModelObject::cut(size_t instance, std::array<Vec3d, 4> plane_poi
 
         if (attributes.has(ModelObjectCutAttribute::CreateDowels) && !dowels.empty()) {
             for (auto dowel : dowels) {
-                invalidate_translations(dowel, instances[instance]);
-
                 reset_instance_transformation(dowel, instance, Transform3d::Identity(), false, false, local_dowels_displace);
 
                 local_dowels_displace += dowel->full_raw_mesh_bounding_box().size().cwiseProduct(Vec3d(-1.5, -1.5, 0.0));
@@ -2323,9 +2356,15 @@ void ModelObject::split(ModelObjectPtrs* new_objects)
             {
                 Vec3d shift = model_instance->get_transformation().get_matrix(true) * new_vol->get_offset();
                 model_instance->set_offset(model_instance->get_offset() + shift);
+                
                 //BBS: add assemble_view related logic
-                model_instance->set_assemble_transformation(model_instance->get_transformation());
+                Geometry::Transformation instance_transformation_copy = model_instance->get_transformation();
-                model_instance->set_offset_to_assembly(new_vol->get_offset());
+                instance_transformation_copy.set_offset(-new_vol->get_offset());
+                const Transform3d &assemble_matrix = model_instance->get_assemble_transformation().get_matrix();
+                const Transform3d &instance_inverse_matrix = instance_transformation_copy.get_matrix().inverse();
+                Transform3d new_instance_inverse_matrix = instance_inverse_matrix * model_instance->get_transformation().get_matrix(true).inverse();
+                Transform3d new_assemble_transform      = assemble_matrix * new_instance_inverse_matrix;
+                model_instance->set_assemble_from_transform(new_assemble_transform);
             }
 
             new_vol->set_offset(Vec3d::Zero());
@@ -2749,11 +2788,23 @@ void ModelVolume::apply_tolerance()
 
     Vec3d sf = get_scaling_factor();
     // make a "hole" wider
-    sf[X] *= 1. + double(cut_info.radius_tolerance);
+    double size_scale = 1.f;
-    sf[Y] *= 1. + double(cut_info.radius_tolerance);
+    if (abs(cut_info.radius - 0) < EPSILON) // For compatibility with old files
+        size_scale = 1.f + double(cut_info.radius_tolerance);
+    else
+        size_scale = (double(cut_info.radius) + double(cut_info.radius_tolerance)) / double(cut_info.radius);
+
+    sf[X] *= size_scale;
+    sf[Y] *= size_scale;
 
     // make a "hole" dipper
-    sf[Z] *= 1. + double(cut_info.height_tolerance);
+    double height_scale = 1.f;
+    if (abs(cut_info.height - 0) < EPSILON)  // For compatibility with old files
+        height_scale = 1.f + double(cut_info.height_tolerance);
+    else
+        height_scale = (double(cut_info.height) + double(cut_info.height_tolerance)) / double(cut_info.height);
+
+    sf[Z] *= height_scale;
 
     set_scaling_factor(sf);
 }
@@ -3368,19 +3419,18 @@ void ModelInstance::get_arrange_polygon(void *ap, const Slic3r::DynamicPrintConf
 
     //BBS: add materials related information
     ModelVolume *volume = NULL;
-    for (size_t i = 0; i < object->volumes.size(); ++ i) {
+    for (size_t i = 0; i < object->volumes.size(); ++i) {
-        if (object->volumes[i]->is_model_part())
+        if (object->volumes[i]->is_model_part()) {
-        {
             volume = object->volumes[i];
-            break;
+            if (!volume) {
+                BOOST_LOG_TRIVIAL(error) << __FUNCTION__ << "invalid object, should not happen";
+                return;
+            }
+            auto ve = object->volumes[i]->get_extruders();
+            ret.extrude_ids.insert(ret.extrude_ids.end(), ve.begin(), ve.end());
         }
     }
-    if (!volume)
+
-    {
-        BOOST_LOG_TRIVIAL(error) << __FUNCTION__ << "invalid object, should not happen";
-        return;
-    }
-    ret.extrude_ids = volume->get_extruders();
     // get per-object support extruders
     auto op = object->get_config_value<ConfigOptionBool>(config_global, "enable_support");
     bool is_support_enabled = op && op->getBool();

src/libslic3r/Model.hpp

@@ -511,6 +511,10 @@ public:
     ModelObjectPtrs segment(size_t instance, unsigned int max_extruders, double smoothing_alpha = 0.5, int segment_number = 5);
     void split(ModelObjectPtrs* new_objects);
     void merge();
+
+    // BBS: Boolean opts - Musang King
+    bool make_boolean(ModelObject *cut_object, const std::string &boolean_opts);
+
     ModelObjectPtrs merge_volumes(std::vector<int>& vol_indeces);//BBS
     // Support for non-uniform scaling of instances. If an instance is rotated by angles, which are not multiples of ninety degrees,
     // then the scaling in world coordinate system is not representable by the Geometry::Transformation structure.
@@ -698,7 +702,8 @@ enum class EnforcerBlockerType : int8_t {
     Extruder13,
     Extruder14,
     Extruder15,
-    ExtruderMax
+    Extruder16,
+    ExtruderMax = Extruder16
 };
 
 enum class ConversionType : int {
@@ -839,12 +844,15 @@ public:
         bool             is_connector{false};
         bool             is_processed{true};
         CutConnectorType connector_type{CutConnectorType::Plug};
+        float            radius{0.f};
+        float            height{0.f};
         float            radius_tolerance{0.f}; // [0.f : 1.f]
         float            height_tolerance{0.f}; // [0.f : 1.f]
 
         CutInfo() = default;
-        CutInfo(CutConnectorType type, float rad_tolerance, float h_tolerance, bool processed = false)
+        CutInfo(CutConnectorType type, float radius_, float height_, float rad_tolerance, float h_tolerance, bool processed = false)
-            : is_connector(true), is_processed(processed), connector_type(type), radius_tolerance(rad_tolerance), height_tolerance(h_tolerance)
+            : is_connector(true), is_processed(processed), connector_type(type)
+            , radius(radius_), height(height_), radius_tolerance(rad_tolerance), height_tolerance(h_tolerance)
         {}
 
         void set_processed() { is_processed = true; }

src/libslic3r/ModelArrange.cpp

@@ -157,6 +157,11 @@ ArrangePolygon get_instance_arrange_poly(ModelInstance* instance, const Slic3r::
     }        
 #else
     ap.brim_width = 0;
+    // For by-layer printing, need to shrink bed a little, so the support won't go outside bed.
+    // We set it to 5mm because that's how much a normal support will grow by default.
+    auto supp_type_ptr = obj->get_config_value<ConfigOptionBool>(config, "enable_support");
+    if (supp_type_ptr && supp_type_ptr->getBool())
+        ap.brim_width = 5.0;
 #endif
     
     ap.height = obj->bounding_box().size().z();

src/libslic3r/Preset.cpp

@@ -705,14 +705,44 @@ bool Preset::has_lidar(PresetBundle *preset_bundle)
     return has_lidar;
 }
 
+BedType Preset::get_default_bed_type(PresetBundle* preset_bundle)
+{
+    if (config.has("default_bed_type") && !config.opt_string("default_bed_type").empty()) {
+        try {
+            std::string str_bed_type = config.opt_string("default_bed_type");
+            int bed_type_value = atoi(str_bed_type.c_str());
+            return BedType(bed_type_value);
+        } catch(...) {
+            ;
+        }
+    }
+
+    std::string model_id = this->get_printer_type(preset_bundle);
+    if (model_id == "BL-P001" || model_id == "BL-P002") {
+        return BedType::btPC;
+    } else if (model_id == "C11") {
+        return BedType::btPEI;
+    }
+    return BedType::btPEI;
+}
+
+bool Preset::has_cali_lines(PresetBundle* preset_bundle)
+{
+    std::string model_id = this->get_printer_type(preset_bundle);
+    if (model_id == "BL-P001" || model_id == "BL-P002") {
+        return true;
+    }
+    return false;
+}
+
 static std::vector<std::string> s_Preset_print_options {
     "layer_height", "initial_layer_print_height", "wall_loops", "slice_closing_radius", "spiral_mode", "slicing_mode",
     "top_shell_layers", "top_shell_thickness", "bottom_shell_layers", "bottom_shell_thickness",
     "ensure_vertical_shell_thickness", "reduce_crossing_wall", "detect_thin_wall", "detect_overhang_wall",
     "seam_position", "staggered_inner_seams", "wall_infill_order", "sparse_infill_density", "sparse_infill_pattern", "top_surface_pattern", "bottom_surface_pattern",
     "infill_direction",
-    "minimum_sparse_infill_area", "reduce_infill_retraction",
+    "minimum_sparse_infill_area", "reduce_infill_retraction","internal_solid_infill_pattern",
-    "ironing_type", "ironing_flow", "ironing_speed", "ironing_spacing",
+    "ironing_type", "ironing_pattern", "ironing_flow", "ironing_speed", "ironing_spacing",
     "max_travel_detour_distance",
     "fuzzy_skin", "fuzzy_skin_thickness", "fuzzy_skin_point_distance",
 #ifdef HAS_PRESSURE_EQUALIZER
@@ -729,7 +759,7 @@ static std::vector<std::string> s_Preset_print_options {
     "independent_support_layer_height",
     "support_angle", "support_interface_top_layers", "support_interface_bottom_layers",
     "support_interface_pattern", "support_interface_spacing", "support_interface_loop_pattern",
-    "support_top_z_distance", "support_on_build_plate_only","support_critical_regions_only", "bridge_no_support", "thick_bridges", "max_bridge_length", "print_sequence",
+    "support_top_z_distance", "support_on_build_plate_only","support_critical_regions_only", "bridge_no_support", "thick_bridges", "max_bridge_length", "print_sequence", "support_remove_small_overhang",
     "filename_format", "wall_filament", "support_bottom_z_distance",
     "sparse_infill_filament", "solid_infill_filament", "support_filament", "support_interface_filament",
     "ooze_prevention", "standby_temperature_delta", "interface_shells", "line_width", "initial_layer_line_width",
@@ -1960,8 +1990,9 @@ Preset& PresetCollection::load_preset(const std::string &path, const std::string
 }
 
 //BBS: add project embedded preset logic
-void PresetCollection::save_current_preset(const std::string &new_name, bool detach, bool save_to_project)
+void PresetCollection::save_current_preset(const std::string &new_name, bool detach, bool save_to_project, Preset* _curr_preset)
 {
+    Preset curr_preset = _curr_preset ? *_curr_preset : m_edited_preset;
     //BBS: add lock logic for sync preset in background
     std::string final_inherits;
     lock();
@@ -1980,7 +2011,7 @@ void PresetCollection::save_current_preset(const std::string &new_name, bool det
             return;
         }
         // Overwriting an existing preset.
-        preset.config = std::move(m_edited_preset.config);
+        preset.config = std::move(curr_preset.config);
         // The newly saved preset will be activated -> make it visible.
         preset.is_visible = true;
         //TODO: remove the detach logic
@@ -1997,7 +2028,7 @@ void PresetCollection::save_current_preset(const std::string &new_name, bool det
         unlock();
     } else {
         // Creating a new preset.
-        Preset       &preset   = *m_presets.insert(it, m_edited_preset);
+        Preset       &preset   = *m_presets.insert(it, curr_preset);
         std::string  &inherits = preset.inherits();
         std::string   old_name = preset.name;
         preset.name = new_name;

src/libslic3r/Preset.hpp

@@ -303,6 +303,8 @@ public:
     bool is_custom_defined();
 
     bool has_lidar(PresetBundle *preset_bundle);
+    BedType get_default_bed_type(PresetBundle *preset_bundle);
+    bool has_cali_lines(PresetBundle* preset_bundle);
 
 
 
@@ -474,7 +476,7 @@ public:
     // a new preset is stored into the list of presets.
     // All presets are marked as not modified and the new preset is activated.
     //BBS: add project embedded preset logic
-    void            save_current_preset(const std::string &new_name, bool detach = false, bool save_to_project = false);
+    void            save_current_preset(const std::string &new_name, bool detach = false, bool save_to_project = false, Preset* _curr_preset = nullptr);
 
     // Delete the current preset, activate the first visible preset.
     // returns true if the preset was deleted successfully.

src/libslic3r/PresetBundle.cpp

@@ -43,7 +43,7 @@ static std::vector<std::string> s_project_options {
 
 //BBS: add BBL as default
 const char *PresetBundle::BBL_BUNDLE = "Custom";
-const char *PresetBundle::BBL_DEFAULT_PRINTER_MODEL = "";
+const char *PresetBundle::BBL_DEFAULT_PRINTER_MODEL = "MyKlipper 0.4 nozzle";
 const char *PresetBundle::BBL_DEFAULT_PRINTER_VARIANT = "0.4";
 const char *PresetBundle::BBL_DEFAULT_FILAMENT = "My Generic PLA";
 
@@ -255,6 +255,8 @@ PresetsConfigSubstitutions PresetBundle::load_presets(AppConfig &config, Forward
 
     this->load_selections(config, preferred_selection);
 
+    set_calibrate_printer("");
+
     //BBS: add config related logs
     BOOST_LOG_TRIVIAL(info) << __FUNCTION__ << boost::format(" finished, returned substitutions %1%")%substitutions.size();
     return substitutions;
@@ -419,6 +421,12 @@ void PresetBundle::reset_project_embedded_presets()
         Preset* selected_filament = this->filaments.find_preset(filament_presets[i], false);
         if (!selected_filament) {
             //it should be the project embedded presets
+            Preset& current_printer = this->printers.get_selected_preset();
+            const std::vector<std::string> &prefered_filament_profiles = current_printer.config.option<ConfigOptionStrings>("default_filament_profile")->values;
+            const std::string prefered_filament_profile = prefered_filament_profiles.empty() ? std::string() : prefered_filament_profiles.front();
+            if (!prefered_filament_profile.empty())
+                filament_presets[i] = prefered_filament_profile;
+            else
             filament_presets[i] = this->filaments.first_visible().name;
         }
     }
@@ -525,23 +533,32 @@ PresetsConfigSubstitutions PresetBundle::load_user_presets(std::string user, For
     // BBS do not load sla_print
     // BBS: change directoties by design
     try {
+        std::string print_selected_preset_name = prints.get_selected_preset().name;
         this->prints.load_presets(dir_user_presets, PRESET_PRINT_NAME, substitutions, substitution_rule);
+        prints.select_preset_by_name(print_selected_preset_name, false);
     } catch (const std::runtime_error &err) {
         errors_cummulative += err.what();
     }
     try {
+        std::string filament_selected_preset_name = filaments.get_selected_preset().name;
         this->filaments.load_presets(dir_user_presets, PRESET_FILAMENT_NAME, substitutions, substitution_rule);
+        filaments.select_preset_by_name(filament_selected_preset_name, false);
     } catch (const std::runtime_error &err) {
         errors_cummulative += err.what();
     }
     try {
+        std::string printer_selected_preset_name = printers.get_selected_preset().name;
         this->printers.load_presets(dir_user_presets, PRESET_PRINTER_NAME, substitutions, substitution_rule);
+        printers.select_preset_by_name(printer_selected_preset_name, false);
     } catch (const std::runtime_error &err) {
         errors_cummulative += err.what();
     }
     if (!errors_cummulative.empty()) throw Slic3r::RuntimeError(errors_cummulative);
     this->update_multi_material_filament_presets();
     this->update_compatible(PresetSelectCompatibleType::Never);
+
+    set_calibrate_printer("");
+
     return PresetsConfigSubstitutions();
 }
 
@@ -609,6 +626,8 @@ PresetsConfigSubstitutions PresetBundle::load_user_presets(AppConfig &
     this->update_compatible(PresetSelectCompatibleType::Never);
     //this->load_selections(config, PresetPreferences());
 
+    set_calibrate_printer("");
+
     if (! errors_cummulative.empty())
         throw Slic3r::RuntimeError(errors_cummulative);
 
@@ -1535,8 +1554,8 @@ unsigned int PresetBundle::sync_ams_list(unsigned int &unknowns)
             BOOST_LOG_TRIVIAL(warning) << __FUNCTION__ << boost::format(": filament_id %1% not found or system or compatible") % filament_id;
             auto filament_type = "Generic " + ams.opt_string("filament_type", 0u);
             iter = std::find_if(filaments.begin(), filaments.end(), [&filament_type](auto &f) { return f.is_compatible && f.is_system
-                    && boost::algorithm::starts_with(f.name, filament_type);
+                        && boost::algorithm::starts_with(f.name, filament_type);
-            });
+                });
             if (iter == filaments.end())
                 iter = std::find_if(filaments.begin(), filaments.end(), [&filament_type](auto &f) { return f.is_compatible && f.is_system; });
             if (iter == filaments.end())
@@ -1557,6 +1576,29 @@ unsigned int PresetBundle::sync_ams_list(unsigned int &unknowns)
     return filament_presets.size();
 }
 
+void PresetBundle::set_calibrate_printer(std::string name)
+{
+    if (name.empty()) {
+        calibrate_filaments.clear();
+        return;
+    }
+    if (!name.empty())
+        calibrate_printer = printers.find_preset(name);
+    const Preset &                printer_preset = calibrate_printer ? *calibrate_printer : printers.get_edited_preset();
+    const PresetWithVendorProfile active_printer = printers.get_preset_with_vendor_profile(printer_preset);
+    DynamicPrintConfig            config;
+    config.set_key_value("printer_preset", new ConfigOptionString(active_printer.preset.name));
+    const ConfigOption *opt = active_printer.preset.config.option("nozzle_diameter");
+    if (opt) config.set_key_value("num_extruders", new ConfigOptionInt((int) static_cast<const ConfigOptionFloats *>(opt)->values.size()));
+    calibrate_filaments.clear();
+    for (size_t i = filaments.num_default_presets(); i < filaments.size(); ++i) {
+        const Preset &                preset                          = filaments.m_presets[i];
+        const PresetWithVendorProfile this_preset_with_vendor_profile = filaments.get_preset_with_vendor_profile(preset);
+        bool                          is_compatible                   = is_compatible_with_printer(this_preset_with_vendor_profile, active_printer, &config);
+        if (is_compatible) calibrate_filaments.insert(&preset);
+    }
+}
+
 //BBS: check whether this is the only edited filament
 bool PresetBundle::is_the_only_edited_filament(unsigned int filament_index)
 {

src/libslic3r/PresetBundle.hpp

@@ -88,6 +88,7 @@ public:
 
     // Orca: update selected filament and print
     void           update_selections(AppConfig &config);
+    void set_calibrate_printer(std::string name);
 
     PresetCollection            prints;
     PresetCollection            sla_prints;
@@ -102,6 +103,9 @@ public:
     std::vector<std::string>    filament_presets;
     // BBS: ams
     std::vector<DynamicPrintConfig> filament_ams_list;
+    // Calibrate
+    Preset const * calibrate_printer = nullptr;
+    std::set<Preset const *> calibrate_filaments;
 
     // The project configuration values are kept separated from the print/filament/printer preset,
     // they are being serialized / deserialized from / to the .amf, .3mf, .config, .gcode,

src/libslic3r/PrintConfig.cpp

@@ -267,7 +267,7 @@ CONFIG_OPTION_ENUM_DEFINE_STATIC_MAPS(ForwardCompatibilitySubstitutionRule)
 
 static const t_config_enum_values s_keys_map_OverhangFanThreshold = {
     { "0%",         Overhang_threshold_none },
-    { "5%",         Overhang_threshold_1_4  },
+    { "10%",         Overhang_threshold_1_4  },
     { "25%",        Overhang_threshold_2_4  },
     { "50%",        Overhang_threshold_3_4  },
     { "75%",        Overhang_threshold_4_4  },
@@ -673,13 +673,13 @@ void PrintConfigDef::init_fff_params()
     def->enum_keys_map = &ConfigOptionEnum<OverhangFanThreshold>::get_enum_values();
     def->mode = comAdvanced;
     def->enum_values.emplace_back("0%");
-    def->enum_values.emplace_back("5%");
+    def->enum_values.emplace_back("10%");
     def->enum_values.emplace_back("25%");
     def->enum_values.emplace_back("50%");
     def->enum_values.emplace_back("75%");
     def->enum_values.emplace_back("95%");
     def->enum_labels.emplace_back("0%");
-    def->enum_labels.emplace_back("5%");
+    def->enum_labels.emplace_back("10%");
     def->enum_labels.emplace_back("25%");
     def->enum_labels.emplace_back("50%");
     def->enum_labels.emplace_back("75%");
@@ -1061,6 +1061,15 @@ void PrintConfigDef::init_fff_params()
     def->enum_labels = def_top_fill_pattern->enum_labels;
     def->set_default_value(new ConfigOptionEnum<InfillPattern>(ipRectilinear));
 
+	def                = this->add("internal_solid_infill_pattern", coEnum);
+    def->label         = L("Internal solid infill pattern");
+    def->category      = L("Strength");
+    def->tooltip       = L("Line pattern of internal solid infill. if the detect nattow internal solid infill be enabled, the concentric pattern will be used for the small area.");
+    def->enum_keys_map = &ConfigOptionEnum<InfillPattern>::get_enum_values();
+    def->enum_values   = def_top_fill_pattern->enum_values;
+    def->enum_labels   = def_top_fill_pattern->enum_labels;
+    def->set_default_value(new ConfigOptionEnum<InfillPattern>(ipRectilinear));
+    
     def = this->add("outer_wall_line_width", coFloatOrPercent);
     def->label = L("Outer wall");
     def->category = L("Quality");
@@ -1348,6 +1357,8 @@ void PrintConfigDef::init_fff_params()
     def->enum_values.push_back("PET-CF");
     def->enum_values.push_back("PETG-CF");
     def->enum_values.push_back("PVA");
+    def->enum_values.push_back("HIPS");
+    def->enum_values.push_back("PLA-AERO");
     def->mode = comSimple;
     def->set_default_value(new ConfigOptionStrings { "PLA" });
 
@@ -1388,6 +1399,9 @@ void PrintConfigDef::init_fff_params()
     def->cli = ConfigOptionDef::nocli;
 
     def = this->add("filament_vendor", coStrings);
+    def->label = L("Vendor");
+    def->tooltip = L("Vendor of filament. For show only");
+    def->mode = comAdvanced;
     def->set_default_value(new ConfigOptionStrings{L("(Undefined)")});
     def->cli = ConfigOptionDef::nocli;
 
@@ -2028,6 +2042,17 @@ void PrintConfigDef::init_fff_params()
     def->mode = comAdvanced;
     def->set_default_value(new ConfigOptionEnum<IroningType>(IroningType::NoIroning));
 
+    def                = this->add("ironing_pattern", coEnum);
+    def->label         = L("Ironing Pattern");
+    def->category      = L("Quality");
+    def->enum_keys_map = &ConfigOptionEnum<InfillPattern>::get_enum_values();
+    def->enum_values.push_back("concentric");
+    def->enum_values.push_back("zig-zag");
+    def->enum_labels.push_back(L("Concentric"));
+    def->enum_labels.push_back(L("Rectilinear"));
+    def->mode = comAdvanced;
+    def->set_default_value(new ConfigOptionEnum<InfillPattern>(ipRectilinear));
+    
     def = this->add("ironing_flow", coPercent);
     def->label = L("Ironing flow");
     def->category = L("Quality");
@@ -2994,6 +3019,13 @@ void PrintConfigDef::init_fff_params()
     def->mode     = comAdvanced;
     def->set_default_value(new ConfigOptionBool(false));
 
+    def = this->add("support_remove_small_overhang", coBool);
+    def->label = L("Remove small overhangs");
+    def->category = L("Support");
+    def->tooltip = L("Remove small overhangs that possibly need no supports.");
+    def->mode = comAdvanced;
+    def->set_default_value(new ConfigOptionBool(true));
+
     // BBS: change type to common float.
     // It may be rounded to mulitple layer height when independent_support_layer_height is false.
     def = this->add("support_top_z_distance", coFloat);
@@ -4491,6 +4523,8 @@ void PrintConfigDef::handle_legacy(t_config_option_key &opt_key, std::string &va
                 ReplaceString(value, split_key, copy_key);
             }
         }
+    } else if (opt_key == "overhang_fan_threshold" && value == "5%") {
+        value = "10%";
     }
 
     // Ignore the following obsolete configuration keys:
@@ -4502,7 +4536,7 @@ void PrintConfigDef::handle_legacy(t_config_option_key &opt_key, std::string &va
         , "max_volumetric_extrusion_rate_slope_positive", "max_volumetric_extrusion_rate_slope_negative"
 #endif /* HAS_PRESSURE_EQUALIZER */
         // BBS
-        , "support_sharp_tails","remove_small_overhangs", "support_with_sheath",
+        , "support_sharp_tails","support_remove_small_overhangs", "support_with_sheath",
         "tree_support_branch_diameter_angle", "tree_support_collision_resolution", "tree_support_with_infill",
         "max_volumetric_speed", "max_print_speed",
         "support_closing_radius",
@@ -4970,6 +5004,11 @@ std::map<std::string, std::string> validate(const FullPrintConfig &cfg, bool und
         error_message.emplace("bottom_surface_pattern", L("invalid value ") + cfg.bottom_surface_pattern.serialize());
     }
 
+    // --soild-fill-pattern
+    if (!print_config_def.get("internal_solid_infill_pattern")->has_enum_value(cfg.internal_solid_infill_pattern.serialize())) {
+        error_message.emplace("internal_solid_infill_pattern", L("invalid value ") + cfg.internal_solid_infill_pattern.serialize());
+    }
+
     // --fill-density
     if (fabs(cfg.sparse_infill_density.value - 100.) < EPSILON &&
         ! print_config_def.get("top_surface_pattern")->has_enum_value(cfg.sparse_infill_pattern.serialize())) {
@@ -5168,14 +5207,14 @@ CLIActionsConfigDef::CLIActionsConfigDef()
     /*def = this->add("export_amf", coBool);
     def->label = L("Export AMF");
     def->tooltip = L("Export the model(s) as AMF.");
-    def->set_default_value(new ConfigOptionBool(false));
+    def->set_default_value(new ConfigOptionBool(false));*/
 
     def = this->add("export_stl", coBool);
     def->label = L("Export STL");
-    def->tooltip = L("Export the model(s) as STL.");
+    def->tooltip = L("Export the objects as multiple STL.");
     def->set_default_value(new ConfigOptionBool(false));
 
-    def = this->add("export_gcode", coBool);
+    /*def = this->add("export_gcode", coBool);
     def->label = L("Export G-code");
     def->tooltip = L("Slice the model and export toolpaths as G-code.");
     def->cli = "export-gcode|gcode|g";
@@ -5207,6 +5246,12 @@ CLIActionsConfigDef::CLIActionsConfigDef()
     def->cli = "uptodate";
     def->set_default_value(new ConfigOptionBool(false));
 
+    def = this->add("load_defaultfila", coBool);
+    def->label = L("Load default filaments");
+    def->tooltip = L("Load first filament as default for those not loaded");
+    def->cli_params = "option";
+    def->set_default_value(new ConfigOptionBool(false));
+
     def = this->add("mtcpp", coInt);
     def->label = L("mtcpp");
     def->tooltip = L("max triangle count per plate for slicing.");
@@ -5307,6 +5352,12 @@ CLITransformConfigDef::CLITransformConfigDef()
     //def->cli = "arrange|a";
     def->set_default_value(new ConfigOptionInt(0));
 
+    def = this->add("repetitions", coInt);
+    def->label = L("Repetions count");
+    def->tooltip = L("Repetions count of the whole model");
+    def->cli_params = "count";
+    def->set_default_value(new ConfigOptionInt(1));
+
     /*def = this->add("ensure_on_bed", coBool);
     def->label = L("Ensure on bed");
     def->tooltip = L("Lift the object above the bed when it is partially below. Enabled by default, use --no-ensure-on-bed to disable.");
@@ -5412,12 +5463,18 @@ CLIMiscConfigDef::CLIMiscConfigDef()
     def->cli_params = "\"filament1.json;filament2.json;...\"";
     def->set_default_value(new ConfigOptionStrings());
 
-    def = this->add("skip_objects", coStrings);
+    def = this->add("skip_objects", coInts);
     def->label = L("Skip Objects");
     def->tooltip = L("Skip some objects in this print");
-    def->cli_params = "\"3;5;10;77\"";
+    def->cli_params = "\"3,5,10,77\"";
     def->set_default_value(new ConfigOptionInts());
 
+    def = this->add("uptodate_settings", coStrings);
+    def->label = L("load uptodate process/machine settings when using uptodate");
+    def->tooltip = L("load uptodate process/machine settings from the specified file when using uptodate");
+    def->cli_params = "\"setting1.json;setting2.json\"";
+    def->set_default_value(new ConfigOptionStrings());
+
     /*def = this->add("output", coString);
     def->label = L("Output File");
     def->tooltip = L("The file where the output will be written (if not specified, it will be based on the input file).");

src/libslic3r/PrintConfig.hpp

@@ -663,6 +663,7 @@ PRINT_CONFIG_CLASS_DEFINE(
     ((ConfigOptionFloat,               support_angle))
     ((ConfigOptionBool,                support_on_build_plate_only))
     ((ConfigOptionBool,                support_critical_regions_only))
+    ((ConfigOptionBool,                support_remove_small_overhang))
     ((ConfigOptionFloat,               support_top_z_distance))
     ((ConfigOptionFloat,               support_bottom_z_distance))
     ((ConfigOptionInt,                 enforce_support_layers))
@@ -731,6 +732,7 @@ PRINT_CONFIG_CLASS_DEFINE(
     ((ConfigOptionBool,                 ensure_vertical_shell_thickness))
     ((ConfigOptionEnum<InfillPattern>,  top_surface_pattern))
     ((ConfigOptionEnum<InfillPattern>,  bottom_surface_pattern))
+    ((ConfigOptionEnum<InfillPattern>, internal_solid_infill_pattern))
     ((ConfigOptionFloatOrPercent,       outer_wall_line_width))
     ((ConfigOptionFloat,                outer_wall_speed))
     ((ConfigOptionFloat,                infill_direction))
@@ -748,6 +750,7 @@ PRINT_CONFIG_CLASS_DEFINE(
     ((ConfigOptionBool, infill_combination))
     // Ironing options
     ((ConfigOptionEnum<IroningType>, ironing_type))
+    ((ConfigOptionEnum<InfillPattern>, ironing_pattern))
     ((ConfigOptionPercent, ironing_flow))
     ((ConfigOptionFloat, ironing_spacing))
     ((ConfigOptionFloat, ironing_speed))

src/libslic3r/PrintObject.cpp

@@ -855,6 +855,7 @@ bool PrintObject::invalidate_state_by_config_options(
         } else if (
                opt_key == "top_surface_pattern"
             || opt_key == "bottom_surface_pattern"
+            || opt_key == "internal_solid_infill_pattern"
             || opt_key == "external_fill_link_max_length"
             || opt_key == "sparse_infill_pattern"
             || opt_key == "infill_anchor"

src/libslic3r/PrintObjectSlice.cpp

@@ -504,14 +504,28 @@ bool groupingVolumes(std::vector<VolumeSlices> objSliceByVolume, std::vector<gro
     std::vector<int> groupIndex(objSliceByVolume.size(), -1);
     double offsetValue = 0.05 / SCALING_FACTOR;
 
+    std::vector<std::vector<int>> osvIndex;
     for (int i = 0; i != objSliceByVolume.size(); ++i) {
         for (int j = 0; j != objSliceByVolume[i].slices.size(); ++j) {
-            objSliceByVolume[i].slices[j] = offset_ex(objSliceByVolume[i].slices[j], offsetValue);
+            osvIndex.push_back({ i,j });
-            for (ExPolygon& poly_ex : objSliceByVolume[i].slices[j])
-                poly_ex.douglas_peucker(resolution);
         }
     }
 
+    tbb::parallel_for(tbb::blocked_range<int>(0, osvIndex.size()),
+        [&osvIndex, &objSliceByVolume, &offsetValue, &resolution](const tbb::blocked_range<int>& range) {
+            for (auto k = range.begin(); k != range.end(); ++k) {
+                for (ExPolygon& poly_ex : objSliceByVolume[osvIndex[k][0]].slices[osvIndex[k][1]])
+                    poly_ex.douglas_peucker(resolution);
+            }
+        });
+
+    tbb::parallel_for(tbb::blocked_range<int>(0, osvIndex.size()),
+        [&osvIndex, &objSliceByVolume,&offsetValue, &resolution](const tbb::blocked_range<int>& range) {
+            for (auto k = range.begin(); k != range.end(); ++k) {
+                objSliceByVolume[osvIndex[k][0]].slices[osvIndex[k][1]] = offset_ex(objSliceByVolume[osvIndex[k][0]].slices[osvIndex[k][1]], offsetValue);
+            }
+        });
+
     for (int i = 0; i != objSliceByVolume.size(); ++i) {
         if (groupIndex[i] < 0) {
             groupIndex[i] = i;
@@ -596,27 +610,43 @@ void applyNegtiveVolumes(ModelVolumePtrs model_volumes, const std::vector<Volume
     }
 }
 
-void reGroupingLayerPolygons(std::vector<groupedVolumeSlices>& gvss, ExPolygons eps)
+void reGroupingLayerPolygons(std::vector<groupedVolumeSlices>& gvss, ExPolygons &eps, double resolution)
 {
     std::vector<int> epsIndex;
     epsIndex.resize(eps.size(), -1);
-    for (int ie = 0; ie != eps.size(); ie++) {
+
-        if (eps[ie].area() <= 0)
+    auto gvssc = gvss;
-            continue;
+    auto epsc = eps;
-        double minArea = eps[ie].area();
+
-        for (int iv = 0; iv != gvss.size(); iv++) {
+    for (ExPolygon& poly_ex : epsc)
-            auto clipedExPolys = diff_ex(eps[ie], gvss[iv].slices);
+        poly_ex.douglas_peucker(resolution);
-            double area = 0;
+
-            for (const auto& ce : clipedExPolys) {
+    for (int i = 0; i != gvssc.size(); ++i) {
-                area += ce.area();
+        for (ExPolygon& poly_ex : gvssc[i].slices)
-            }
+            poly_ex.douglas_peucker(resolution);
-            if (area < minArea) {
-                minArea = area;
-                epsIndex[ie] = iv;
-            }
-        }
     }
 
+    tbb::parallel_for(tbb::blocked_range<int>(0, epsc.size()),
+        [&epsc, &gvssc, &epsIndex](const tbb::blocked_range<int>& range) {
+            for (auto ie = range.begin(); ie != range.end(); ++ie) {
+                if (epsc[ie].area() <= 0)
+                    continue;
+
+                double minArea = epsc[ie].area();
+                for (int iv = 0; iv != gvssc.size(); iv++) {
+                    auto clipedExPolys = diff_ex(epsc[ie], gvssc[iv].slices);
+                    double area = 0;
+                    for (const auto& ce : clipedExPolys) {
+                        area += ce.area();
+                    }
+                    if (area < minArea) {
+                        minArea = area;
+                        epsIndex[ie] = iv;
+                    }
+                }
+            }
+        });
+
     for (int iv = 0; iv != gvss.size(); iv++)
         gvss[iv].slices.clear();
 
@@ -663,9 +693,10 @@ std::string fix_slicing_errors(PrintObject* object, LayerPtrs &layers, const std
     }
 
     BOOST_LOG_TRIVIAL(debug) << "Slicing objects - fixing slicing errors in parallel - begin";
+    std::atomic<bool> is_replaced = false;
     tbb::parallel_for(
         tbb::blocked_range<size_t>(0, buggy_layers.size()),
-        [&layers, &throw_if_canceled, &buggy_layers, &error_msg](const tbb::blocked_range<size_t>& range) {
+        [&layers, &throw_if_canceled, &buggy_layers, &is_replaced](const tbb::blocked_range<size_t>& range) {
             for (size_t buggy_layer_idx = range.begin(); buggy_layer_idx < range.end(); ++ buggy_layer_idx) {
                 throw_if_canceled();
                 size_t idx_layer = buggy_layers[buggy_layer_idx];
@@ -712,7 +743,7 @@ std::string fix_slicing_errors(PrintObject* object, LayerPtrs &layers, const std
                         }
                     if (!expolys.empty()) {
                         //BBS
-                        error_msg = L("Empty layers around bottom are replaced by nearest normal layers.");
+                        is_replaced = true;
                         layerm->slices.set(union_ex(expolys), stInternal);
                     }
                 }
@@ -723,6 +754,9 @@ std::string fix_slicing_errors(PrintObject* object, LayerPtrs &layers, const std
     throw_if_canceled();
     BOOST_LOG_TRIVIAL(debug) << "Slicing objects - fixing slicing errors in parallel - end";
 
+    if(is_replaced)
+        error_msg = L("Empty layers around bottom are replaced by nearest normal layers.");
+
     // remove empty layers from bottom
     while (! layers.empty() && (layers.front()->lslices.empty() || layers.front()->empty())) {
         delete layers.front();
@@ -752,7 +786,7 @@ void groupingVolumesForBrim(PrintObject* object, LayerPtrs& layers, int firstLay
     applyNegtiveVolumes(object->model_object()->volumes, object->firstLayerObjSliceMod(), object->firstLayerObjGroupsMod(), scaled_resolution);
 
     // BBS: the actual first layer slices stored in layers are re-sorted by volume group and will be used to generate brim
-    reGroupingLayerPolygons(object->firstLayerObjGroupsMod(), layers.front()->lslices);
+    reGroupingLayerPolygons(object->firstLayerObjGroupsMod(), layers.front()->lslices, scaled_resolution);
 }
 
 // Called by make_perimeters()
@@ -777,7 +811,6 @@ void PrintObject::slice()
     m_layers = new_layers(this, generate_object_layers(m_slicing_params, layer_height_profile));
     this->slice_volumes();
     m_print->throw_if_canceled();
-
     int firstLayerReplacedBy = 0;
 
 #if 1
@@ -1137,8 +1170,12 @@ void PrintObject::slice_volumes()
                                                                  std::min(0.f, xy_hole_scaled),
                                                                  trimming);
                             //BBS: trim surfaces
-                            for (size_t region_id = 0; region_id < layer->regions().size(); ++region_id)
+                            for (size_t region_id = 0; region_id < layer->regions().size(); ++region_id) {
-                                layer->regions()[region_id]->trim_surfaces(to_polygons(trimming));
+                                // BBS: split trimming result by region
+                                ExPolygons contour_exp = to_expolygons(std::move(layer->regions()[region_id]->slices.surfaces));
+
+                                layer->regions()[region_id]->slices.set(intersection_ex(contour_exp, to_polygons(trimming)), stInternal);
+                            }
                         }
 	                }
 	                // Merge all regions' slices to get islands, chain them by a shortest path.

src/libslic3r/ProjectTask.cpp

@@ -185,4 +185,11 @@ namespace Slic3r {
         project_path.clear();
     }
 
+    BBLModelTask::BBLModelTask()
+    {
+        job_id      = -1;
+        design_id   = -1;
+        profile_id  = -1;
+    }
+
 } // namespace Slic3r

src/libslic3r/ProjectTask.hpp

@@ -17,6 +17,7 @@ namespace Slic3r {
 class BBLProject;
 class BBLProfile;
 class BBLTask;
+class BBLModelTask;
 
 
 enum MachineBedType {
@@ -95,6 +96,20 @@ enum TaskUserOptions {
     OPTIONS_RECORD_TIMELAPSE = 4
 };
 
+class BBLModelTask {
+public:
+    BBLModelTask();
+    ~BBLModelTask() {}
+
+    int                         job_id;
+    int                         design_id;
+    int                         profile_id;
+    std::string                 task_id;
+    std::string                 model_id;
+    std::string                 model_name;
+    std::string                 profile_name;
+};
+
 class BBLSubTask {
 public:
     enum SubTaskStatus {
@@ -112,6 +127,7 @@ public:
     BBLSubTask(const BBLSubTask& obj) {
         task_id             = obj.task_id;
         parent_id           = obj.parent_id;
+        task_model_id       = obj.task_model_id;
         task_project_id     = obj.task_project_id;
         task_profile_id     = obj.task_profile_id;
         task_name           = obj.task_name;
@@ -127,9 +143,14 @@ public:
         task_flow_cali      = obj.task_flow_cali;
         task_vibration_cali = obj.task_vibration_cali;
         task_layer_inspect  = obj.task_layer_inspect;
+
+        job_id              = obj.job_id;
+        origin_model_name   = obj.origin_model_name;
+        origin_profile_name = obj.origin_profile_name;
     }
 
     std::string     task_id;            /* plate id */
+    std::string     task_model_id;      /* model id */
     std::string     task_project_id;    /* project id */
     std::string     task_profile_id;    /* profile id*/
     std::string     task_name;          /* task name, generally filename as task name */
@@ -161,6 +182,10 @@ public:
     BBLTask*        parent_task_;
     std::string     parent_id;
 
+    int             job_id;
+    std::string     origin_model_name;
+    std::string     origin_profile_name;
+
     int parse_content_json(std::string json_str);
     static BBLSubTask::SubTaskStatus parse_status(std::string status);
     static BBLSubTask::SubTaskStatus parse_user_service_task_status(int status);
@@ -186,6 +211,7 @@ public:
     std::wstring                task_dst_url;       /* put task to dest url in machine */
     BBLProfile*                 profile_;
     std::string                 task_project_id;
+    std::string                 task_model_id;
     std::string                 task_profile_id;
     std::vector<BBLSubTask*>    subtasks;
     std::map<std::string, BBLSliceInfo*> slice_info; /* slice info of subtasks, key: plate idx, 1, 2, 3, etc... */

src/libslic3r/ShortestPath.cpp

@@ -1057,6 +1057,16 @@ void chain_and_reorder_extrusion_paths(std::vector<ExtrusionPath> &extrusion_pat
 	reorder_extrusion_paths(extrusion_paths, chain_extrusion_paths(extrusion_paths, start_near));
 }
 
+std::vector<size_t> chain_expolygons(const ExPolygons &input_exploy) {
+	Points points;
+	for (const ExPolygon &exploy : input_exploy) {
+		BoundingBox bbox;
+		bbox = get_extents(exploy);
+		points.push_back(bbox.center());
+	}
+	return chain_points(points);
+}
+
 std::vector<size_t> chain_points(const Points &points, Point *start_near)
 {
 	auto segment_end_point = [&points](size_t idx, bool /* first_point */) -> const Point& { return points[idx]; };

src/libslic3r/ShortestPath.hpp

@@ -13,6 +13,7 @@ namespace ClipperLib { class PolyNode; }
 namespace Slic3r {
 
 std::vector<size_t> 				 chain_points(const Points &points, Point *start_near = nullptr);
+std::vector<size_t> 				 chain_expolygons(const ExPolygons &input_exploy);
 
 std::vector<std::pair<size_t, bool>> chain_extrusion_entities(std::vector<ExtrusionEntity*> &entities, const Point *start_near = nullptr);
 void                                 reorder_extrusion_entities(std::vector<ExtrusionEntity*> &entities, const std::vector<std::pair<size_t, bool>> &chain);

src/libslic3r/Slicing.cpp

@@ -190,32 +190,47 @@ std::vector<coordf_t> layer_height_profile_from_ranges(
     // 2) Convert the trimmed ranges to a height profile, fill in the undefined intervals between z=0 and z=slicing_params.object_print_z_max()
     // with slicing_params.layer_height
     std::vector<coordf_t> layer_height_profile;
-    for (std::vector<std::pair<t_layer_height_range,coordf_t>>::const_iterator it_range = ranges_non_overlapping.begin(); it_range != ranges_non_overlapping.end(); ++ it_range) {
+    auto last_z = [&layer_height_profile]() {
-        coordf_t lo = it_range->first.first;
+        return layer_height_profile.empty() ? 0. : *(layer_height_profile.end() - 2);
-        coordf_t hi = it_range->first.second;
+    };
-        coordf_t height = it_range->second;
+    auto lh_append = [&layer_height_profile](coordf_t z, coordf_t layer_height) {
-        coordf_t last_z      = layer_height_profile.empty() ? 0. : layer_height_profile[layer_height_profile.size() - 2];
+        if (!layer_height_profile.empty()) {
-        if (lo > last_z + EPSILON) {
+            bool last_z_matches = is_approx(*(layer_height_profile.end() - 2), z);
+            bool last_h_matches = is_approx(layer_height_profile.back(), layer_height);
+            if (last_h_matches) {
+                if (last_z_matches) {
+                    // Drop a duplicate.
+                    return;
+                }
+                if (layer_height_profile.size() >= 4 && is_approx(*(layer_height_profile.end() - 3), layer_height)) {
+                    // Third repetition of the same layer_height. Update z of the last entry.
+                    *(layer_height_profile.end() - 2) = z;
+                    return;
+                }
+            }
+        }
+        layer_height_profile.push_back(z);
+        layer_height_profile.push_back(layer_height);
+    };
+
+    for (const std::pair<t_layer_height_range, coordf_t>& non_overlapping_range : ranges_non_overlapping) {
+        coordf_t lo = non_overlapping_range.first.first;
+        coordf_t hi = non_overlapping_range.first.second;
+        coordf_t height = non_overlapping_range.second;
+        if (coordf_t z = last_z(); lo > z + EPSILON) {
             // Insert a step of normal layer height.
-            layer_height_profile.push_back(last_z);
+            lh_append(z, slicing_params.layer_height);
-            layer_height_profile.push_back(slicing_params.layer_height);
+            lh_append(lo, slicing_params.layer_height);
-            layer_height_profile.push_back(lo);
-            layer_height_profile.push_back(slicing_params.layer_height);
         }
         // Insert a step of the overriden layer height.
-        layer_height_profile.push_back(lo);
+        lh_append(lo, height);
-        layer_height_profile.push_back(height);
+        lh_append(hi, height);
-        layer_height_profile.push_back(hi);
-        layer_height_profile.push_back(height);
     }
 
-    coordf_t last_z      = layer_height_profile.empty() ? 0. : layer_height_profile[layer_height_profile.size() - 2];
+    if (coordf_t z = last_z(); z < slicing_params.object_print_z_height()) {
-    if (last_z < slicing_params.object_print_z_height()) {
         // Insert a step of normal layer height up to the object top.
-        layer_height_profile.push_back(last_z);
+        lh_append(z, slicing_params.layer_height);
-        layer_height_profile.push_back(slicing_params.layer_height);
+        lh_append(slicing_params.object_print_z_height(), slicing_params.layer_height);
-        layer_height_profile.push_back(slicing_params.object_print_z_height());
-        layer_height_profile.push_back(slicing_params.layer_height);
     }
 
    	return layer_height_profile;

src/libslic3r/SupportMaterial.cpp

@@ -1634,25 +1634,28 @@ static inline ExPolygons detect_overhangs(
                 //FIXME add user defined filtering here based on minimal area or minimum radius or whatever.
 
                 // BBS
-                for (ExPolygon& expoly : layerm->raw_slices) {
+                if (g_config_support_sharp_tails) {
-                    bool is_sharp_tail = false;
+                    for (ExPolygon& expoly : layerm->raw_slices) {
-                    float accum_height = layer.height;
+                        if (offset_ex(expoly, -0.5 * fw).empty()) continue;
+                        bool is_sharp_tail = false;
+                        float accum_height = layer.height;
 
-                    // 1. nothing below
+                        // 1. nothing below
-                    // Check whether this is a sharp tail region.
+                        // Check whether this is a sharp tail region.
-                    // Should use lower_layer_expolys without any offset. Otherwise, it may missing sharp tails near the main body.
+                        // Should use lower_layer_expolys without any offset. Otherwise, it may missing sharp tails near the main body.
-                    if (g_config_support_sharp_tails && !overlaps(offset_ex(expoly, 0.5 * fw), lower_layer_expolys)) {
+                        if (!overlaps(offset_ex(expoly, 0.5 * fw), lower_layer_expolys)) {
-                        is_sharp_tail = expoly.area() < area_thresh_well_supported && !offset_ex(expoly,-0.1*fw).empty();
+                            is_sharp_tail = expoly.area() < area_thresh_well_supported && !offset_ex(expoly, -0.1 * fw).empty();
-                    }
+                        }
 
-                    if (is_sharp_tail) {
+                        if (is_sharp_tail) {
-                        ExPolygons overhang = diff_ex({ expoly }, lower_layer_polygons);
+                            ExPolygons overhang = diff_ex({ expoly }, lower_layer_expolys);
-                        layer.sharp_tails.push_back(expoly);
+                            layer.sharp_tails.push_back(expoly);
-                        layer.sharp_tails_height.insert({ &expoly, accum_height });
+                            layer.sharp_tails_height.insert({ &expoly, accum_height });
-                        overhang = offset_ex(overhang, 0.05 * fw);
+                            overhang = offset_ex(overhang, 0.05 * fw);
-                        polygons_append(diff_polygons, to_polygons(overhang));
+                            polygons_append(diff_polygons, to_polygons(overhang));
+                        }
                     }
-                }               
+                }
             }
 
             if (diff_polygons.empty())
@@ -1790,13 +1793,21 @@ static inline std::tuple<Polygons, Polygons, double> detect_contacts(
                 // For the same reason, the non-bridging support area may be smaller than the bridging support area!
                 slices_margin_update(std::min(lower_layer_offset, float(scale_(gap_xy))), no_interface_offset);
                 // Offset the contact polygons outside.
-
-                // BBS: already trim the support in trim_support_layers_by_object()
 #if 0
+                for (size_t i = 0; i < NUM_MARGIN_STEPS; ++ i) {
+                    diff_polygons = diff(
+                        offset(
+                            diff_polygons,
+                            scaled<float>(SUPPORT_MATERIAL_MARGIN / NUM_MARGIN_STEPS),
+                            ClipperLib::jtRound,
+                            // round mitter limit
+                            scale_(0.05)),
+                        slices_margin.polygons);
+                }
+#else
                 diff_polygons = diff(diff_polygons, slices_margin.polygons);
 #endif
             }
-
             polygons_append(contact_polygons, diff_polygons);
         } // for each layer.region
 
@@ -2255,21 +2266,18 @@ PrintObjectSupportMaterial::MyLayersPtr PrintObjectSupportMaterial::top_contact_
     const coordf_t extrusion_width = m_object_config->line_width.get_abs_value(object.print()->config().nozzle_diameter.get_at(object.config().support_interface_filament-1));
     const coordf_t extrusion_width_scaled = scale_(extrusion_width);
     if (is_auto(m_object_config->support_type.value) && g_config_support_sharp_tails && !detect_first_sharp_tail_only) {
-        for (size_t layer_nr = 0; layer_nr < object.layer_count(); layer_nr++) {
+        for (size_t layer_nr = layer_id_start; layer_nr < num_layers; layer_nr++) {
             if (object.print()->canceled())
                 break;
 
             const Layer* layer = object.get_layer(layer_nr);
             const Layer* lower_layer = layer->lower_layer;
-            // skip if:
+            if (!lower_layer)
-            // 1) if the current layer is already detected as sharp tails
-            // 2) lower layer has no sharp tails
-            if (!lower_layer || layer->sharp_tails.empty() == false || lower_layer->sharp_tails.empty() == true)
                 continue;
 
             // BBS detect sharp tail
             const ExPolygons& lower_layer_sharptails = lower_layer->sharp_tails;
-            auto& lower_layer_sharptails_height = lower_layer->sharp_tails_height;
+            const auto& lower_layer_sharptails_height = lower_layer->sharp_tails_height;
             for (const ExPolygon& expoly : layer->lslices) {
                 bool  is_sharp_tail = false;
                 float accum_height = layer->height;
@@ -2300,13 +2308,13 @@ PrintObjectSupportMaterial::MyLayersPtr PrintObjectSupportMaterial::top_contact_
                     }
 
                     // 2.3 check whether sharp tail exceed the max height
-                    for (auto& lower_sharp_tail_height : lower_layer_sharptails_height) {
+                    for (const auto& lower_sharp_tail_height : lower_layer_sharptails_height) {
                         if (lower_sharp_tail_height.first->overlaps(expoly)) {
                             accum_height += lower_sharp_tail_height.second;
                             break;
                         }
                     }
-                    if (accum_height >= sharp_tail_max_support_height) {
+                    if (accum_height > sharp_tail_max_support_height) {
                         is_sharp_tail = false;
                         break;
                     }
@@ -2343,7 +2351,8 @@ PrintObjectSupportMaterial::MyLayersPtr PrintObjectSupportMaterial::top_contact_
         return MyLayersPtr();
 
     // BBS group overhang clusters
-    if (g_config_remove_small_overhangs) {
+    const bool config_remove_small_overhangs = m_object_config->support_remove_small_overhang.value;
+    if (config_remove_small_overhangs) {
         std::vector<OverhangCluster> clusters;
       double fw_scaled = scale_(extrusion_width);
         std::set<ExPolygon*> removed_overhang;
@@ -2371,8 +2380,9 @@ PrintObjectSupportMaterial::MyLayersPtr PrintObjectSupportMaterial::top_contact_
             if (!cluster.is_sharp_tail && !cluster.is_cantilever) {
                 // 2. check overhang cluster size is small
                 cluster.is_small_overhang = false;
-                auto erode1 = offset_ex(cluster.merged_overhangs_dilated, -2.5 * fw_scaled);
+                auto erode1 = offset_ex(cluster.merged_overhangs_dilated, -1.0 * fw_scaled);
-                if (area(erode1) < SQ(scale_(0.1))) {
+                Point bbox_sz = get_extents(erode1).size();
+                if (bbox_sz.x() < 2 * fw_scaled || bbox_sz.y() < 2 * fw_scaled) {
                     cluster.is_small_overhang = true;
                 }
             }
@@ -2824,41 +2834,10 @@ PrintObjectSupportMaterial::MyLayersPtr PrintObjectSupportMaterial::bottom_conta
     return bottom_contacts;
 }
 
-// FN_HIGHER_EQUAL: the provided object pointer has a Z value >= of an internal threshold.
-// Find the first item with Z value >= of an internal threshold of fn_higher_equal.
-// If no vec item with Z value >= of an internal threshold of fn_higher_equal is found, return vec.size()
-// If the initial idx is size_t(-1), then use binary search.
-// Otherwise search linearly upwards.
-template<typename IteratorType, typename IndexType, typename FN_HIGHER_EQUAL>
-IndexType idx_higher_or_equal(IteratorType begin, IteratorType end, IndexType idx, FN_HIGHER_EQUAL fn_higher_equal)
-{
-    auto size = int(end - begin);
-    if (size == 0) {
-        idx = 0;
-    } else if (idx == IndexType(-1)) {
-        // First of the batch of layers per thread pool invocation. Use binary search.
-        int idx_low  = 0;
-        int idx_high = std::max(0, size - 1);
-        while (idx_low + 1 < idx_high) {
-            int idx_mid  = (idx_low + idx_high) / 2;
-            if (fn_higher_equal(begin[idx_mid]))
-                idx_high = idx_mid;
-            else
-                idx_low  = idx_mid;
-        }
-        idx =  fn_higher_equal(begin[idx_low])  ? idx_low  :
-              (fn_higher_equal(begin[idx_high]) ? idx_high : size);
-    } else {
-        // For the other layers of this batch of layers, search incrementally, which is cheaper than the binary search.
-        while (int(idx) < size && ! fn_higher_equal(begin[idx]))
-            ++ idx;
-    }
-    return idx;
-}
 template<typename T, typename IndexType, typename FN_HIGHER_EQUAL>
 IndexType idx_higher_or_equal(const std::vector<T>& vec, IndexType idx, FN_HIGHER_EQUAL fn_higher_equal)
 {
-    return idx_higher_or_equal(vec.begin(), vec.end(), idx, fn_higher_equal);
+    return Layer::idx_higher_or_equal(vec.begin(), vec.end(), idx, fn_higher_equal);
 }
 
 // FN_LOWER_EQUAL: the provided object pointer has a Z value <= of an internal threshold.
@@ -3343,7 +3322,7 @@ void PrintObjectSupportMaterial::trim_support_layers_by_object(
                 assert(! support_layer.polygons.empty() && support_layer.print_z >= m_slicing_params.raft_contact_top_z + EPSILON);
                 // Find the overlapping object layers including the extra above / below gap.
                 coordf_t z_threshold = support_layer.bottom_print_z() - gap_extra_below + EPSILON;
-                idx_object_layer_overlapping = idx_higher_or_equal(
+                idx_object_layer_overlapping = Layer::idx_higher_or_equal(
                     object.layers().begin(), object.layers().end(), idx_object_layer_overlapping,
                     [z_threshold](const Layer *layer){ return layer->print_z >= z_threshold; });
                 // Collect all the object layers intersecting with this layer.
@@ -4633,6 +4612,40 @@ void PrintObjectSupportMaterial::generate_toolpaths(
             }
 #endif
 
+            // Calculate top interface angle
+            float angle_of_biggest_bridge = -1.f;
+            do
+            {
+                // Currently only works when thick_bridges is off
+                if (m_object->config().thick_bridges)
+                    break;
+
+                coordf_t object_layer_bottom_z = support_layer.print_z + m_slicing_params.gap_support_object;
+                const Layer* object_layer = m_object->get_layer_at_bottomz(object_layer_bottom_z, 10.0 * EPSILON);
+                if (object_layer == nullptr)
+                    break;
+
+                if (object_layer != nullptr) {
+                    float biggest_bridge_area = 0.f;
+                    const Polygons& top_contact_polys = top_contact_layer.polygons_to_extrude();
+                    for (auto layerm : object_layer->regions()) {
+                        for (auto bridge_surface : layerm->fill_surfaces.filter_by_type(stBottomBridge)) {
+                            float bs_area = bridge_surface->area();
+                            if (bs_area <= biggest_bridge_area || bridge_surface->bridge_angle < 0.f)
+                                continue;
+
+                            angle_of_biggest_bridge = bridge_surface->bridge_angle;
+                            biggest_bridge_area = bs_area;
+                        }
+                    }
+                }
+            } while (0);
+
+            auto calc_included_angle_degree = [](int degree_a, int degree_b) {
+                int iad = std::abs(degree_b - degree_a);
+                return std::min(iad, 180 - iad);
+            };
+
             // Top and bottom contacts, interface layers.
             for (size_t i = 0; i < 3; ++ i) {
                 MyLayerExtruded &layer_ex = (i == 0) ? top_contact_layer : (i == 1 ? bottom_contact_layer : interface_layer);
@@ -4655,6 +4668,22 @@ void PrintObjectSupportMaterial::generate_toolpaths(
                         // Use interface angle for the interface layers.
                         m_support_params.interface_angle + interface_angle_delta;
 
+                // BBS
+                bool can_adjust_top_interface_angle = (m_object_config->support_interface_top_layers.value > 1 && &layer_ex == &top_contact_layer);
+                if (can_adjust_top_interface_angle && angle_of_biggest_bridge >= 0.f) {
+                    int bridge_degree = (int)Geometry::rad2deg(angle_of_biggest_bridge);
+                    int support_intf_degree = (int)Geometry::rad2deg(filler_interface->angle);
+                    int max_included_degree = 0;
+                    int step = 90;
+                    for (int add_on_degree = 0; add_on_degree < 180; add_on_degree += step) {
+                        int degree_to_try = support_intf_degree + add_on_degree;
+                        int included_degree = calc_included_angle_degree(bridge_degree, degree_to_try);
+                        if (included_degree > max_included_degree) {
+                            max_included_degree = included_degree;
+                            filler_interface->angle = Geometry::deg2rad((float)degree_to_try);
+                        }
+                    }
+                }
                 double density = interface_as_base ? m_support_params.support_density : m_support_params.interface_density;
                 filler_interface->spacing = interface_as_base ? m_support_params.support_material_flow.spacing() : m_support_params.support_material_interface_flow.spacing();
                 filler_interface->link_max_length = coord_t(scale_(filler_interface->spacing * link_max_length_factor / density));

src/libslic3r/Surface.hpp

@@ -107,6 +107,7 @@ public:
 	bool   is_external() const { return this->is_top() || this->is_bottom(); }
 	bool   is_internal() const { return ! this->is_external(); }
 	bool   is_solid()    const { return this->is_external() || this->surface_type == stInternalSolid || this->surface_type == stInternalBridge; }
+	bool   is_solid_infill() const { return this->surface_type == stInternalSolid; }
 };
 
 typedef std::vector<Surface> Surfaces;

src/libslic3r/Thread.cpp

@@ -187,6 +187,26 @@ std::optional<std::string> get_current_thread_name()
 
 #endif // _WIN32
 
+// To be called at the start of the application to save the current thread ID as the main (UI) thread ID.
+static boost::thread::id g_main_thread_id;
+
+void save_main_thread_id()
+{
+	g_main_thread_id = boost::this_thread::get_id();
+}
+
+// Retrieve the cached main (UI) thread ID.
+boost::thread::id get_main_thread_id()
+{
+	return g_main_thread_id;
+}
+
+// Checks whether the main (UI) thread is active.
+bool is_main_thread_active()
+{
+	return get_main_thread_id() == boost::this_thread::get_id();
+}
+
 // Spawn (n - 1) worker threads on Intel TBB thread pool and name them by an index and a system thread ID.
 // Also it sets locale of the worker threads to "C" for the G-code generator to produce "." as a decimal separator.
 void name_tbb_thread_pool_threads_set_locale()

src/libslic3r/Thread.hpp

@@ -26,6 +26,13 @@ inline bool set_thread_name(boost::thread &thread, const std::string &thread_nam
 bool set_current_thread_name(const char *thread_name);
 inline bool set_current_thread_name(const std::string &thread_name) { return set_current_thread_name(thread_name.c_str()); }
 
+// To be called at the start of the application to save the current thread ID as the main (UI) thread ID.
+void save_main_thread_id();
+// Retrieve the cached main (UI) thread ID.
+boost::thread::id get_main_thread_id();
+// Checks whether the main (UI) thread is active.
+bool is_main_thread_active();
+
 // Returns nullopt if not supported.
 // Not supported by OSX.
 // Naming threads is only supported on newer Windows 10.

src/libslic3r/TreeSupport.cpp

@@ -33,8 +33,6 @@
 namespace Slic3r
 {
 #define unscale_(val) ((val) * SCALING_FACTOR)
-#define FIRST_LAYER_EXPANSION 1.2
-
 
 inline unsigned int round_divide(unsigned int dividend, unsigned int divisor) //!< Return dividend divided by divisor rounded to the nearest integer
 {
@@ -734,6 +732,7 @@ void TreeSupport::detect_overhangs(bool detect_first_sharp_tail_only)
     const coordf_t max_bridge_length = scale_(config.max_bridge_length.value);
     const bool bridge_no_support = max_bridge_length > 0;
     const bool support_critical_regions_only = config.support_critical_regions_only.value;
+    const bool config_remove_small_overhangs = config.support_remove_small_overhang.value;
     const int enforce_support_layers = config.enforce_support_layers.value;
     const double area_thresh_well_supported = SQ(scale_(6));
     const double length_thresh_well_supported = scale_(6);
@@ -870,9 +869,11 @@ void TreeSupport::detect_overhangs(bool detect_first_sharp_tail_only)
                     }
                 }
                 ExPolygons curr_polys;
+                std::vector<const ExPolygon*> curr_poly_ptrs;
                 for (const ExPolygon& expoly : layer->lslices) {
                     if (!offset_ex(expoly, -extrusion_width_scaled / 2).empty()) {
                         curr_polys.emplace_back(expoly);
+                        curr_poly_ptrs.emplace_back(&expoly);
                     }
                 }
 
@@ -885,28 +886,30 @@ void TreeSupport::detect_overhangs(bool detect_first_sharp_tail_only)
                     overhang_areas.end());
 
 
-                ExPolygons overhangs_sharp_tail;
                 if (is_auto(stype) && g_config_support_sharp_tails)
                 {
                     // BBS detect sharp tail
-                    const ExPolygons& lower_layer_sharptails = lower_layer->sharp_tails;
+                    for (const ExPolygon* expoly : curr_poly_ptrs) {
-                    auto& lower_layer_sharptails_height = lower_layer->sharp_tails_height;
-                    for (ExPolygon& expoly : layer->lslices) {
                         bool  is_sharp_tail = false;
                         // 1. nothing below
                         // this is a sharp tail region if it's small but non-ignorable
-                        if (!overlaps(offset_ex(expoly, 0.5 * extrusion_width_scaled), lower_polys)) {
+                        if (!overlaps(offset_ex(*expoly, 0.5 * extrusion_width_scaled), lower_polys)) {
-                            is_sharp_tail = expoly.area() < area_thresh_well_supported && !offset_ex(expoly, -0.1 * extrusion_width_scaled).empty();
+                            is_sharp_tail = expoly->area() < area_thresh_well_supported && !offset_ex(*expoly, -0.1 * extrusion_width_scaled).empty();
                         }
 
                         if (is_sharp_tail) {
-                            ExPolygons overhang = diff_ex({ expoly }, lower_layer->lslices);
+                            ExPolygons overhang = diff_ex({ *expoly }, lower_polys);
-                            layer->sharp_tails.push_back(expoly);
+                            layer->sharp_tails.push_back(*expoly);
-                            layer->sharp_tails_height.insert({ &expoly, layer->height });
+                            layer->sharp_tails_height.insert({ expoly, layer->height });
                             append(overhang_areas, overhang);
 
-                            if (!overhang.empty())
+                            if (!overhang.empty()) {
                                 has_sharp_tails = true;
+#ifdef SUPPORT_TREE_DEBUG_TO_SVG
+                                SVG svg(format("SVG/sharp_tail_orig_%.02f.svg", layer->print_z), m_object->bounding_box());
+                                if (svg.is_opened()) svg.draw(overhang, "red");
+#endif
+                            }
                         }                        
                     }
                 }
@@ -953,15 +956,12 @@ void TreeSupport::detect_overhangs(bool detect_first_sharp_tail_only)
             Layer* layer = m_object->get_layer(layer_nr);
             SupportLayer* ts_layer = m_object->get_support_layer(layer_nr + m_raft_layers);
             Layer* lower_layer = layer->lower_layer;
-            // skip if:
+            if (!lower_layer)
-            // 1) if the current layer is already detected as sharp tails
-            // 2) lower layer has no sharp tails
-            if (!lower_layer || layer->sharp_tails.empty() == false || lower_layer->sharp_tails.empty() == true)
                 continue;
 
             // BBS detect sharp tail
             const ExPolygons& lower_layer_sharptails = lower_layer->sharp_tails;
-            auto& lower_layer_sharptails_height = lower_layer->sharp_tails_height;
+            const auto& lower_layer_sharptails_height = lower_layer->sharp_tails_height;
             for (ExPolygon& expoly : layer->lslices) {
                 bool  is_sharp_tail = false;
                 float accum_height = layer->height;
@@ -992,13 +992,13 @@ void TreeSupport::detect_overhangs(bool detect_first_sharp_tail_only)
                     }
 
                     // 2.3 check whether sharp tail exceed the max height
-                    for (auto& lower_sharp_tail_height : lower_layer_sharptails_height) {
+                    for (const auto& lower_sharp_tail_height : lower_layer_sharptails_height) {
                         if (lower_sharp_tail_height.first->overlaps(expoly)) {
                             accum_height += lower_sharp_tail_height.second;
                             break;
                         }
                     }
-                    if (accum_height >= sharp_tail_max_support_height) {
+                    if (accum_height > sharp_tail_max_support_height) {
                         is_sharp_tail = false;
                         break;
                     }
@@ -1024,8 +1024,8 @@ void TreeSupport::detect_overhangs(bool detect_first_sharp_tail_only)
                     if (!overhang.empty())
                         has_sharp_tails = true;
 #ifdef SUPPORT_TREE_DEBUG_TO_SVG
-                    SVG svg(get_svg_filename(std::to_string(layer->print_z), "sharp_tail"), m_object->bounding_box());
+                    SVG svg(format("SVG/sharp_tail_%.02f.svg",layer->print_z), m_object->bounding_box());
-                    if (svg.is_opened()) svg.draw(overhang, "yellow");
+                    if (svg.is_opened()) svg.draw(overhang, "red");
 #endif
                 }
 
@@ -1050,7 +1050,7 @@ void TreeSupport::detect_overhangs(bool detect_first_sharp_tail_only)
     auto blockers  = m_object->slice_support_blockers();
     m_object->project_and_append_custom_facets(false, EnforcerBlockerType::ENFORCER, enforcers);
     m_object->project_and_append_custom_facets(false, EnforcerBlockerType::BLOCKER, blockers);
-    if (is_auto(stype) && g_config_remove_small_overhangs) {
+    if (is_auto(stype) && config_remove_small_overhangs) {
         if (blockers.size() < m_object->layer_count())
             blockers.resize(m_object->layer_count());
         for (auto& cluster : overhangClusters) {
@@ -1066,18 +1066,25 @@ void TreeSupport::detect_overhangs(bool detect_first_sharp_tail_only)
 
             if (!cluster.is_sharp_tail && !cluster.is_cantilever) {
                 // 2. check overhang cluster size is smaller than 3.0 * fw_scaled
-                auto erode1 = offset_ex(cluster.merged_poly, -1.5 * extrusion_width_scaled);
+                auto erode1 = offset_ex(cluster.merged_poly, -1 * extrusion_width_scaled);
-                cluster.is_small_overhang = area(erode1) < SQ(scale_(0.1));
+                Point bbox_sz = get_extents(erode1).size();
+                if (bbox_sz.x() < 2 * extrusion_width_scaled || bbox_sz.y() < 2 * extrusion_width_scaled) {
+                    cluster.is_small_overhang = true;
+                }
             }
 
 #ifdef SUPPORT_TREE_DEBUG_TO_SVG
             const Layer* layer1 = m_object->get_layer(cluster.min_layer);
             BoundingBox bbox = cluster.merged_bbox;
             bbox.merge(get_extents(layer1->lslices));
-            SVG svg(format("SVG/overhangCluster_%s_%s_tail=%s_cantilever=%s_small=%s.svg", cluster.min_layer, layer1->print_z, cluster.is_sharp_tail, cluster.is_cantilever, cluster.is_small_overhang), bbox);
+            SVG svg(format("SVG/overhangCluster_%s-%s_%s-%s_tail=%s_cantilever=%s_small=%s.svg",
+                cluster.min_layer, cluster.max_layer, layer1->print_z, m_object->get_layer(cluster.max_layer)->print_z,
+                cluster.is_sharp_tail, cluster.is_cantilever, cluster.is_small_overhang), bbox);
             if (svg.is_opened()) {
                 svg.draw(layer1->lslices, "red");
                 svg.draw(cluster.merged_poly, "blue");
+                svg.draw_text(bbox.min + Point(scale_(0), scale_(2)), "lslices", "red", 2);
+                svg.draw_text(bbox.min + Point(scale_(0), scale_(2)), "overhang", "blue", 2);
             }
 #endif
 
@@ -1100,7 +1107,7 @@ void TreeSupport::detect_overhangs(bool detect_first_sharp_tail_only)
         SupportLayer* ts_layer = m_object->get_support_layer(layer_nr + m_raft_layers);
         auto layer = m_object->get_layer(layer_nr);
         auto lower_layer = layer->lower_layer;
-        if (support_critical_regions_only) {
+        if (support_critical_regions_only && is_auto(stype)) {
             ts_layer->overhang_areas.clear();
             if (lower_layer == nullptr)
                 ts_layer->overhang_areas = layer->sharp_tails;
@@ -1112,7 +1119,9 @@ void TreeSupport::detect_overhangs(bool detect_first_sharp_tail_only)
 
         if (layer_nr < blockers.size()) {
             Polygons& blocker = blockers[layer_nr];
-            ts_layer->overhang_areas = diff_ex(ts_layer->overhang_areas, offset_ex(blocker, scale_(radius_sample_resolution)));
+            // Arthur: union_ is a must because after mirroring, the blocker polygons are in left-hand coordinates, ie clockwise, 
+            // which are not valid polygons, and will be removed by offset_ex. union_ can make these polygons right.
+            ts_layer->overhang_areas = diff_ex(ts_layer->overhang_areas, offset_ex(union_(blocker), scale_(radius_sample_resolution)));
         }
 
         if (max_bridge_length > 0 && ts_layer->overhang_areas.size() > 0 && lower_layer) {
@@ -1124,16 +1133,24 @@ void TreeSupport::detect_overhangs(bool detect_first_sharp_tail_only)
         for (auto &area : ts_layer->overhang_areas) {
             ts_layer->overhang_types.emplace(&area, SupportLayer::Detected);
         }
-        // enforcers
+        // enforcers now follow same logic as normal support. See STUDIO-3692
-        if (layer_nr < enforcers.size()) {
+        if (layer_nr < enforcers.size() && lower_layer) {
+            float no_interface_offset = std::accumulate(layer->regions().begin(), layer->regions().end(), FLT_MAX,
+                [](float acc, const LayerRegion* layerm) { return std::min(acc, float(layerm->flow(frExternalPerimeter).scaled_width())); });
+            Polygons  lower_layer_polygons = (layer_nr == 0) ? Polygons() : to_polygons(lower_layer->lslices);
             Polygons& enforcer = enforcers[layer_nr];
-            // coconut: enforcer can't do offset2_ex, otherwise faces with angle near 90 degrees can't have enforcers, which
+            if (!enforcer.empty()) {
-            // is not good. For example: tails of animals needs extra support except the lowest tip.
+                Polygons enforcer_polygons = diff(intersection(layer->lslices, enforcer),
-            //enforcer = std::move(offset2_ex(enforcer, -0.1 * extrusion_width_scaled, 0.1 * extrusion_width_scaled));
+                    // Inflate just a tiny bit to avoid intersection of the overhang areas with the object.
-            enforcer = offset(enforcer, 0.1 * extrusion_width_scaled);
+                    expand(lower_layer_polygons, 0.05f * no_interface_offset, SUPPORT_SURFACES_OFFSET_PARAMETERS));
-            for (const Polygon& poly : enforcer) {
+                // coconut: enforcer can't do offset2_ex, otherwise faces with angle near 90 degrees can't have enforcers, which
-                ts_layer->overhang_areas.emplace_back(poly);
+                // is not good. For example: tails of animals needs extra support except the lowest tip.
-                ts_layer->overhang_types.emplace(&ts_layer->overhang_areas.back(), SupportLayer::Enforced);
+                //enforcer = std::move(offset2_ex(enforcer, -0.1 * extrusion_width_scaled, 0.1 * extrusion_width_scaled));
+                enforcer_polygons = offset(enforcer_polygons, 0.1 * extrusion_width_scaled);
+                for (const Polygon& poly : enforcer_polygons) {
+                    ts_layer->overhang_areas.emplace_back(poly);
+                    ts_layer->overhang_types.emplace(&ts_layer->overhang_areas.back(), SupportLayer::Enforced);
+                }
             }
         }
 
@@ -1143,13 +1160,15 @@ void TreeSupport::detect_overhangs(bool detect_first_sharp_tail_only)
 
 #ifdef SUPPORT_TREE_DEBUG_TO_SVG
     for (const SupportLayer* layer : m_object->support_layers()) {
-        if (layer->overhang_areas.empty())
+        if (layer->overhang_areas.empty() && (blockers.size()<=layer->id() || blockers[layer->id()].empty()))
             continue;
 
         SVG svg(format("SVG/overhang_areas_%s.svg", layer->print_z), m_object->bounding_box());
         if (svg.is_opened()) {
             svg.draw_outline(m_object->get_layer(layer->id())->lslices, "yellow");
-            svg.draw(layer->overhang_areas, "red");
+            svg.draw(layer->overhang_areas, "orange");
+            if (blockers.size() > layer->id())
+                svg.draw(blockers[layer->id()], "red");
             for (auto& overhang : layer->overhang_areas) {
                 double aarea = overhang.area()/ area_thresh_well_supported;
                 auto pt = get_extents(overhang).center();
@@ -1959,7 +1978,8 @@ coordf_t TreeSupport::calc_branch_radius(coordf_t base_radius, coordf_t mm_to_to
     return radius;
 }
 
-ExPolygons avoid_object_remove_extra_small_parts(ExPolygons &expolys, const ExPolygons &avoid_region) {
+template<typename RegionType> // RegionType could be ExPolygons or Polygons
+ExPolygons avoid_object_remove_extra_small_parts(ExPolygons &expolys, const RegionType&avoid_region) {
     ExPolygons expolys_out;
     for (auto expoly : expolys) {
         auto  expolys_avoid = diff_ex(expoly, avoid_region);
@@ -1977,6 +1997,82 @@ ExPolygons avoid_object_remove_extra_small_parts(ExPolygons &expolys, const ExPo
     return expolys_out;
 }
 
+Polygons TreeSupport::get_trim_support_regions(
+    const PrintObject& object,
+    SupportLayer* support_layer_ptr,
+    const coordf_t       gap_extra_above,
+    const coordf_t       gap_extra_below,
+    const coordf_t       gap_xy)
+{
+    static const double sharp_tail_xy_gap = 0.2f;
+    static const double no_overlap_xy_gap = 0.2f;
+    double gap_xy_scaled = scale_(gap_xy);
+    SupportLayer& support_layer = *support_layer_ptr;
+    auto m_print_config = object.print()->config();
+
+    size_t idx_object_layer_overlapping = size_t(-1);
+
+    auto is_layers_overlap = [](const SupportLayer& support_layer, const Layer& object_layer, coordf_t bridging_height = 0.f) -> bool {
+        if (std::abs(support_layer.print_z - object_layer.print_z) < EPSILON)
+            return true;
+
+        coordf_t object_lh = bridging_height > EPSILON ? bridging_height : object_layer.height;
+        if (support_layer.print_z < object_layer.print_z && support_layer.print_z > object_layer.print_z - object_lh)
+            return true;
+
+        if (support_layer.print_z > object_layer.print_z && support_layer.bottom_z() < object_layer.print_z - EPSILON)
+            return true;
+
+        return false;
+        };
+
+    // Find the overlapping object layers including the extra above / below gap.
+    coordf_t z_threshold = support_layer.bottom_z() - gap_extra_below + EPSILON;
+    idx_object_layer_overlapping = Layer::idx_higher_or_equal(
+        object.layers().begin(), object.layers().end(), idx_object_layer_overlapping,
+        [z_threshold](const Layer* layer) { return layer->print_z >= z_threshold; });
+    // Collect all the object layers intersecting with this layer.
+    Polygons polygons_trimming;
+    size_t i = idx_object_layer_overlapping;
+    for (; i < object.layers().size(); ++i) {
+        const Layer& object_layer = *object.layers()[i];
+        if (object_layer.bottom_z() > support_layer.print_z + gap_extra_above - EPSILON)
+            break;
+
+        bool is_overlap = is_layers_overlap(support_layer, object_layer);
+        for (const ExPolygon& expoly : object_layer.lslices) {
+            // BBS
+            bool is_sharptail = !intersection_ex({ expoly }, object_layer.sharp_tails).empty();
+            coordf_t trimming_offset = is_sharptail ? scale_(sharp_tail_xy_gap) :
+                is_overlap ? gap_xy_scaled :
+                scale_(no_overlap_xy_gap);
+            polygons_append(polygons_trimming, offset({ expoly }, trimming_offset, SUPPORT_SURFACES_OFFSET_PARAMETERS));
+            }
+        }
+    if (!m_slicing_params.soluble_interface && m_object_config->thick_bridges) {
+        // Collect all bottom surfaces, which will be extruded with a bridging flow.
+        for (; i < object.layers().size(); ++i) {
+            const Layer& object_layer = *object.layers()[i];
+            bool some_region_overlaps = false;
+            for (LayerRegion* region : object_layer.regions()) {
+                coordf_t bridging_height = region->region().bridging_height_avg(m_print_config);
+                if (object_layer.print_z - bridging_height > support_layer.print_z + gap_extra_above - EPSILON)
+                    break;
+                some_region_overlaps = true;
+
+                bool is_overlap = is_layers_overlap(support_layer, object_layer, bridging_height);
+                coordf_t trimming_offset = is_overlap ? gap_xy_scaled : scale_(no_overlap_xy_gap);
+                polygons_append(polygons_trimming,
+                    offset(region->fill_surfaces.filter_by_type(stBottomBridge), trimming_offset, SUPPORT_SURFACES_OFFSET_PARAMETERS));
+                }
+            if (!some_region_overlaps)
+                break;
+            }
+        }
+
+    return polygons_trimming;
+}
+
 void TreeSupport::draw_circles(const std::vector<std::vector<Node*>>& contact_nodes)
 {
     const PrintObjectConfig &config = m_object->config();
@@ -1985,6 +2081,7 @@ void TreeSupport::draw_circles(const std::vector<std::vector<Node*>>& contact_no
     int bottom_gap_layers = round(m_slicing_params.gap_object_support / m_slicing_params.layer_height);
     const coordf_t branch_radius = config.tree_support_branch_diameter.value / 2;
     const coordf_t branch_radius_scaled = scale_(branch_radius);
+    bool on_buildplate_only = config.support_on_build_plate_only.value;
     Polygon branch_circle; //Pre-generate a circle with correct diameter so that we don't have to recompute those (co)sines every time.
 
     // Use square support if there are too many nodes per layer because circle support needs much longer time to compute
@@ -2122,7 +2219,8 @@ void TreeSupport::draw_circles(const std::vector<std::vector<Node*>>& contact_no
                         }
                         area.emplace_back(ExPolygon(circle));
                         // merge overhang to get a smoother interface surface
-                        if (top_interface_layers > 0 && node.support_roof_layers_below > 0) {
+                        // Do not merge when buildplate_only is on, because some underneath nodes may have been deleted.
+                        if (top_interface_layers > 0 && node.support_roof_layers_below > 0 && !on_buildplate_only) {
                             ExPolygons overhang_expanded;
                             if (node.overhang->contour.size() > 100 || node.overhang->holes.size()>1)
                                 overhang_expanded.emplace_back(*node.overhang);
@@ -2174,7 +2272,8 @@ void TreeSupport::draw_circles(const std::vector<std::vector<Node*>>& contact_no
                 roof_1st_layer = std::move(offset2_ex(roof_1st_layer, contact_dist_scaled, -contact_dist_scaled));
 
                 // avoid object
-                auto avoid_region_interface = m_ts_data->get_collision(m_ts_data->m_xy_distance, layer_nr);
+                //ExPolygons avoid_region_interface = m_ts_data->get_collision(m_ts_data->m_xy_distance, layer_nr);
+                Polygons avoid_region_interface = get_trim_support_regions(*m_object, ts_layer, m_slicing_params.gap_object_support, m_slicing_params.gap_support_object, m_ts_data->m_xy_distance);
                 if (has_circle_node) {
                     roof_areas = avoid_object_remove_extra_small_parts(roof_areas, avoid_region_interface);
                     roof_1st_layer = avoid_object_remove_extra_small_parts(roof_1st_layer, avoid_region_interface);
@@ -2251,7 +2350,7 @@ void TreeSupport::draw_circles(const std::vector<std::vector<Node*>>& contact_no
             }
         });
 
-#if 1
+
         if (with_lightning_infill)
         {
             const bool global_lightning_infill = true;
@@ -2323,7 +2422,7 @@ void TreeSupport::draw_circles(const std::vector<std::vector<Node*>>& contact_no
         else if (!with_infill) {
             // move the holes to contour so they can be well supported
 
-        // check if poly's contour intersects with expoly's contour
+            // check if poly's contour intersects with expoly's contour
             auto intersects_contour = [](Polygon poly, ExPolygon expoly, Point& pt_on_poly, Point& pt_on_expoly, Point& pt_far_on_poly, float dist_thresh = 0.01) {
                 float min_dist = std::numeric_limits<float>::max();
                 float max_dist = 0;
@@ -2436,7 +2535,7 @@ void TreeSupport::draw_circles(const std::vector<std::vector<Node*>>& contact_no
                     }
                 }
             }
-#endif
+
 
 #ifdef SUPPORT_TREE_DEBUG_TO_SVG
     for (int layer_nr = m_object->layer_count() - 1; layer_nr >= 0; layer_nr--) {
@@ -2731,20 +2830,17 @@ void TreeSupport::drop_nodes(std::vector<std::vector<Node*>>& contact_nodes)
                         node_ = (node.dist_mm_to_top >= neighbour->dist_mm_to_top && p_node->parent) ? p_node : neighbour;
                     else
                         node_ = p_node->parent ? p_node : neighbour;
+                    // Make sure the next pass doesn't drop down either of these (since that already happened).
+                    node_->merged_neighbours.push_front(node_ == p_node ? neighbour : p_node);
                     const bool to_buildplate = !is_inside_ex(m_ts_data->get_avoidance(0, layer_nr_next), next_position);
-                    Node *     next_node     = new Node(next_position, node_->distance_to_top + 1, layer_nr_next, node_->support_roof_layers_below-1, to_buildplate, node_->parent,
+                    Node *     next_node     = new Node(next_position, node_->distance_to_top + 1, layer_nr_next, node_->support_roof_layers_below-1, to_buildplate, node_,
                                                print_z_next, height_next);
                     next_node->movement = next_position - node.position;
                     get_max_move_dist(next_node);
                     next_node->is_merged     = true;
                     contact_nodes[layer_nr_next].push_back(next_node);
 
-                    // make sure the trees are all connected
-                    if (node.parent) node.parent->child = next_node;
-                    if (neighbour->parent) neighbour->parent->child = next_node;
 
-                    // Make sure the next pass doesn't drop down either of these (since that already happened).
-                    node.merged_neighbours.push_front(neighbour);
                     to_delete.insert(neighbour);
                     to_delete.insert(p_node);
                 }
@@ -2977,7 +3073,7 @@ void TreeSupport::drop_nodes(std::vector<std::vector<Node*>>& contact_nodes)
             }
         }
     }
-    #if 0
+    #if 1
     // delete nodes with no children (means either it's a single layer nodes, or the branch has been deleted but not completely)
     for (size_t layer_nr = contact_nodes.size() - 1; layer_nr > 0; layer_nr--){
         auto layer_contact_nodes = contact_nodes[layer_nr];
@@ -3053,16 +3149,8 @@ void TreeSupport::smooth_nodes(std::vector<std::vector<Node *>> &contact_nodes)
             }
         }
     }
-#ifdef SUPPORT_TREE_DEBUG_TO_SVG
     // save tree structure for viewing in python
-    struct TreeNode {
+    auto& tree_nodes = m_ts_data->tree_nodes;
-        Vec3f pos;
-        std::vector<int> children;  // index of children in the storing vector
-        TreeNode(Point pt, float z) {
-            pos = { float(unscale_(pt.x())),float(unscale_(pt.y())),z };
-        }
-    };
-    std::vector<TreeNode> tree_nodes;
     std::map<Node*, int> ptr2idx;
     std::map<int, Node*> idx2ptr;
     for (int layer_nr = 0; layer_nr < contact_nodes.size(); layer_nr++) {
@@ -3078,12 +3166,16 @@ void TreeSupport::smooth_nodes(std::vector<std::vector<Node *>> &contact_nodes)
         Node* p_node = idx2ptr[i];
         if (p_node->child)
             tree_node.children.push_back(ptr2idx[p_node->child]);
+        if(p_node->parent)
+            tree_node.parents.push_back(ptr2idx[p_node->parent]);
     }
+#ifdef SUPPORT_TREE_DEBUG_TO_SVG
     nlohmann::json jj;
     for (size_t i = 0; i < tree_nodes.size(); i++) {
         nlohmann::json j;
         j["pos"] = tree_nodes[i].pos;
         j["children"] = tree_nodes[i].children;
+        j["linked"] = !(tree_nodes[i].pos.z() > 0.205 && tree_nodes[i].children.empty());
         jj.push_back(j);
     }
     
@@ -3356,12 +3448,14 @@ void TreeSupport::generate_contact_points(std::vector<std::vector<TreeSupport::N
                 Point candidate = overhang_bounds.center();
                 if (!overhang_part.contains(candidate))
                     move_inside_expoly(overhang_part, candidate);
-                Node *contact_node     = new Node(candidate, -z_distance_top_layers, layer_nr, support_roof_layers + z_distance_top_layers, true, Node::NO_PARENT, print_z,
+                if (!(config.support_on_build_plate_only && is_inside_ex(m_ts_data->m_layer_outlines_below[layer_nr], candidate))) {
-                                              height, z_distance_top);
+                    Node* contact_node = new Node(candidate, -z_distance_top_layers, layer_nr, support_roof_layers + z_distance_top_layers, true, Node::NO_PARENT, print_z,
-                contact_node->type = ePolygon;
+                        height, z_distance_top);
-                contact_node->overhang = &overhang_part;
+                    contact_node->type = ePolygon;
-                curr_nodes.emplace_back(contact_node);
+                    contact_node->overhang = &overhang_part;
-                continue;
+                    curr_nodes.emplace_back(contact_node);
+                    continue;
+                }
             }
 
             overhang_bounds.inflated(half_overhang_distance);
@@ -3413,7 +3507,8 @@ void TreeSupport::generate_contact_points(std::vector<std::vector<TreeSupport::N
                     curr_nodes.emplace_back(contact_node);
                 }
             }
-            if (ts_layer->overhang_types[&overhang_part] == SupportLayer::Detected) {
+            // add supports at corners for both auto and manual overhangs, github #2008
+            if (/*ts_layer->overhang_types[&overhang_part] == SupportLayer::Detected*/1) {
                 // add points at corners
                 auto &points = overhang_part.contour.points;
                 int   nSize  = points.size();
@@ -3589,7 +3684,6 @@ const ExPolygons& TreeSupportData::calculate_avoidance(const RadiusLayerPair& ke
     const auto& radius = key.radius;
     const auto& layer_nr = key.layer_nr;
     BOOST_LOG_TRIVIAL(debug) << "calculate_avoidance on radius=" << radius << ", layer=" << layer_nr<<", recursion="<<key.recursions;
-    std::pair<tbb::concurrent_unordered_map<RadiusLayerPair, ExPolygons, RadiusLayerPairHash, RadiusLayerPairEquality>::iterator,bool> ret;
     constexpr auto max_recursion_depth = 100;
     if (key.recursions <= max_recursion_depth*2) {
         if (layer_nr == 0) {
@@ -3616,14 +3710,15 @@ const ExPolygons& TreeSupportData::calculate_avoidance(const RadiusLayerPair& ke
         const ExPolygons &collision       = get_collision(radius, layer_nr);
         avoidance_areas.insert(avoidance_areas.end(), collision.begin(), collision.end());
         avoidance_areas = std::move(union_ex(avoidance_areas));
-        ret  = m_avoidance_cache.insert({key, std::move(avoidance_areas)});
+        auto ret = m_avoidance_cache.insert({ key, std::move(avoidance_areas) });
         //assert(ret.second);
+        return ret.first->second;
     } else {
         ExPolygons avoidance_areas = std::move(offset_ex(m_layer_outlines_below[layer_nr], scale_(m_xy_distance + radius)));
-        ret             = m_avoidance_cache.insert({key, std::move(avoidance_areas)});
+        auto ret = m_avoidance_cache.insert({ key, std::move(avoidance_areas) });
         assert(ret.second);
+        return ret.first->second;
     }
-    return ret.first->second;
 }
 
 } //namespace Slic3r

src/libslic3r/TreeSupport.hpp

@@ -20,6 +20,7 @@ namespace Slic3r
 {
 class PrintObject;
 class TreeSupport;
+class SupportLayer;
 
 struct LayerHeightData
 {
@@ -30,6 +31,15 @@ struct LayerHeightData
     LayerHeightData(coordf_t z, coordf_t h, size_t next_layer) : print_z(z), height(h), next_layer_nr(next_layer) {}
 };
 
+struct TreeNode {
+    Vec3f pos;
+    std::vector<int> children;  // index of children in the storing vector
+    std::vector<int> parents;  // index of parents in the storing vector
+    TreeNode(Point pt, float z) {
+        pos = { float(unscale_(pt.x())),float(unscale_(pt.y())),z };
+    }
+};
+
 /*!
  * \brief Lazily generates tree guidance volumes.
  *
@@ -90,6 +100,8 @@ public:
 
     std::vector<LayerHeightData> layer_heights;
 
+    std::vector<TreeNode> tree_nodes;
+
 private:
     /*!
      * \brief Convenience typedef for the keys to the caches
@@ -483,6 +495,14 @@ private:
     Polygons contact_nodes_to_polygon(const std::vector<Node*>& contact_nodes, Polygons layer_contours, int layer_nr, std::vector<double>& radiis, std::vector<bool>& is_interface);
     coordf_t calc_branch_radius(coordf_t base_radius, size_t layers_to_top, size_t tip_layers, double diameter_angle_scale_factor);
     coordf_t calc_branch_radius(coordf_t base_radius, coordf_t mm_to_top, double diameter_angle_scale_factor);
+
+    // similar to SupportMaterial::trim_support_layers_by_object
+    Polygons get_trim_support_regions(
+        const PrintObject& object,
+        SupportLayer* support_layer_ptr,
+        const coordf_t       gap_extra_above,
+        const coordf_t       gap_extra_below,
+        const coordf_t       gap_xy);
 };
 
 }

src/libslic3r/Utils.hpp

@@ -40,6 +40,9 @@
 #define CLI_PROCESS_NOT_COMPATIBLE     -17
 #define CLI_INVALID_VALUES_IN_3MF      -18
 #define CLI_POSTPROCESS_NOT_SUPPORTED  -19
+#define CLI_PRINTABLE_SIZE_REDUCED     -20
+#define CLI_OBJECT_ARRANGE_FAILED      -21
+#define CLI_OBJECT_ORIENT_FAILED       -22
 
 
 #define CLI_NO_SUITABLE_OBJECTS     -50
@@ -53,6 +56,10 @@
 #define CLI_SLICING_TIME_EXCEEDS_LIMIT      -58
 #define CLI_TRIANGLE_COUNT_EXCEEDS_LIMIT    -59
 #define CLI_NO_SUITABLE_OBJECTS_AFTER_SKIP  -60
+#define CLI_FILAMENT_NOT_MATCH_BED_TYPE     -61
+#define CLI_FILAMENTS_DIFFERENT_TEMP        -62
+#define CLI_OBJECT_COLLISION_IN_SEQ_PRINT   -63
+#define CLI_OBJECT_COLLISION_IN_LAYER_PRINT -64
 
 #define CLI_SLICING_ERROR                  -100
 #define CLI_GCODE_PATH_CONFLICTS           -101
@@ -590,6 +597,19 @@ inline std::string get_bbl_remain_time_dhms(float time_in_secs)
 
 bool bbl_calc_md5(std::string &filename, std::string &md5_out);
 
+inline std::string filter_characters(const std::string& str, const std::string& filterChars)
+{
+    std::string filteredStr = str;
+
+    auto removeFunc = [&filterChars](char ch) {
+        return filterChars.find(ch) != std::string::npos;
+    };
+
+    filteredStr.erase(std::remove_if(filteredStr.begin(), filteredStr.end(), removeFunc), filteredStr.end());
+
+    return filteredStr;
+}
+
 void copy_directory_recursively(const boost::filesystem::path &source, const boost::filesystem::path &target);
 
 

src/libslic3r/libslic3r.h

@@ -23,6 +23,7 @@
 #include <cassert>
 #include <cmath>
 #include <type_traits>
+#include <optional>
 
 #ifdef _WIN32
 // On MSVC, std::deque degenerates to a list of pointers, which defeats its purpose of reducing allocator load and memory fragmentation.
@@ -147,6 +148,15 @@ inline void append(std::vector<T>& dest, std::vector<T>&& src)
     src.shrink_to_fit();
 }
 
+template<class T, class... Args> // Arbitrary allocator can be used
+void clear_and_shrink(std::vector<T, Args...>& vec)
+{
+    // shrink_to_fit does not garantee the release of memory nor does it clear()
+    std::vector<T, Args...> tmp;
+    vec.swap(tmp);
+    assert(vec.capacity() == 0);
+}
+
 // Append the source in reverse.
 template <typename T>
 inline void append_reversed(std::vector<T>& dest, const std::vector<T>& src)
@@ -274,9 +284,17 @@ constexpr inline T lerp(const T& a, const T& b, Number t)
 }
 
 template <typename Number>
-constexpr inline bool is_approx(Number value, Number test_value)
+constexpr inline bool is_approx(Number value, Number test_value, Number precision = EPSILON)
 {
-    return std::fabs(double(value) - double(test_value)) < double(EPSILON);
+    return std::fabs(double(value) - double(test_value)) < double(precision);
+}
+
+template<typename Number>
+constexpr inline bool is_approx(const std::optional<Number> &value,
+                                const std::optional<Number> &test_value)
+{
+    return (!value.has_value() && !test_value.has_value()) ||
+        (value.has_value() && test_value.has_value() && is_approx<Number>(*value, *test_value));
 }
 
 // A meta-predicate which is true for integers wider than or equal to coord_t
@@ -347,16 +365,42 @@ public:
     Range(It b, It e) : from(std::move(b)), to(std::move(e)) {}
 
     // Some useful container-like methods...
-    inline size_t size() const { return end() - begin(); }
+    inline size_t size() const { return std::distance(from, to); }
-    inline bool   empty() const { return size() == 0; }
+    inline bool   empty() const { return from == to; }
 };
 
+template<class Cont> auto range(Cont &&cont)
+{
+    return Range{std::begin(cont), std::end(cont)};
+}
+
 template<class T, class = FloatingOnly<T>>
 constexpr T NaN = std::numeric_limits<T>::quiet_NaN();
 
 constexpr float  NaNf = NaN<float>;
 constexpr double NaNd = NaN<double>;
 
+// Rounding up.
+// 1.5 is rounded to 2
+// 1.49 is rounded to 1
+// 0.5 is rounded to 1,
+// 0.49 is rounded to 0
+// -0.5 is rounded to 0,
+// -0.51 is rounded to -1,
+// -1.5 is rounded to -1.
+// -1.51 is rounded to -2.
+// If input is not a valid float (it is infinity NaN or if it does not fit)
+// the float to int conversion produces a max int on Intel and +-max int on ARM.
+template<typename I>
+inline IntegerOnly<I, I> fast_round_up(double a)
+{
+    // Why does Java Math.round(0.49999999999999994) return 1?
+    // https://stackoverflow.com/questions/9902968/why-does-math-round0-49999999999999994-return-1
+    return a == 0.49999999999999994 ? I(0) : I(floor(a + 0.5));
+}
+
+template<class T> using SamePair = std::pair<T, T>;
+
 } // namespace Slic3r
 
 #endif

src/libslic3r/utils.cpp

@@ -55,6 +55,7 @@
 
 #include <boost/algorithm/string/predicate.hpp>
 #include <boost/filesystem.hpp>
+#include <boost/filesystem/path.hpp>
 #include <boost/nowide/fstream.hpp>
 #include <boost/nowide/convert.hpp>
 #include <boost/nowide/cstdio.hpp>

src/mcut/CMakeLists.txt

@@ -0,0 +1,417 @@
+#
+# Copyright (c) 2021-2022 Floyd M. Chitalu.
+# All rights reserved.
+# 
+# NOTE: This file is licensed under GPL-3.0-or-later (default). 
+# A commercial license can be purchased from Floyd M. Chitalu. 
+#  
+# License details:
+# 
+# (A)  GNU General Public License ("GPL"); a copy of which you should have 
+#      recieved with this file.
+# 	    - see also: <http://www.gnu.org/licenses/>
+# (B)  Commercial license.
+#      - email: floyd.m.chitalu@gmail.com
+# 
+# The commercial license options is for users that wish to use MCUT in 
+# their products for comercial purposes but do not wish to release their 
+# software products under the GPL license. 
+# 
+# Author(s)     : Floyd M. Chitalu
+#
+############################################################################################
+#
+# You can configure MCUT with the following CMake options:
+#
+#	MCUT_BUILD_AS_SHARED_LIB [default=ON] - Build MCUT as a shared/dynamic library (.so/.dll). -- SET TO OFF
+#	MCUT_BUILD_DOCUMENTATION [default=OFF] - Build documentation (explicit dependancy on Doxygen) 
+#	MCUT_BUILD_TESTS [default=OFF] - Build the tests (implicit dependancy on GoogleTest)
+#	MCUT_BUILD_TUTORIALS [default=OFF] - Build tutorials
+#	MCUT_BUILD_WITH_COMPUTE_HELPER_THREADPOOL [default=ON] - Build as configurable multi-threaded library
+#
+# This script will define the following CMake cache variables:
+#
+#	MCUT_INCLUDE_DIR - the MCUT include directory
+# 	MCUT_LIB_PATH - path to the MCUT library (i.e. .so/.dll or .a/.lib files)
+
+cmake_minimum_required(VERSION 3.12...3.13 FATAL_ERROR)
+
+project(mcut LANGUAGES CXX C) 
+
+get_directory_property(MCUT_PARENT_DIR PARENT_DIRECTORY)
+if(NOT MCUT_PARENT_DIR)
+	set(MCUT_TOPLEVEL_PROJECT ON)
+else()
+	set(MCUT_TOPLEVEL_PROJECT OFF)
+endif()
+
+set ( DESCRIPTION "Mesh cutting library." )
+
+if (NOT WIN32 AND NOT CMAKE_BUILD_TYPE)
+	message(STATUS "No build type selected, default to Release")
+	set(CMAKE_BUILD_TYPE "Release" CACHE STRING "Choose the type of build, options are: Debug Release RelWithDebInfo MinSizeRel." FORCE)
+endif()
+
+set (CMAKE_DEBUG_POSTFIX "d")
+
+#set(CMAKE_LIBRARY_OUTPUT_DIRECTORY ${CMAKE_BINARY_DIR}/bin)
+#set(CMAKE_ARCHIVE_OUTPUT_DIRECTORY ${CMAKE_BINARY_DIR}/lib)
+#set(CMAKE_RUNTIME_OUTPUT_DIRECTORY ${CMAKE_BINARY_DIR}/bin)
+
+list (APPEND CMAKE_MODULE_PATH "${CMAKE_CURRENT_SOURCE_DIR}/cmake")
+
+set(MCUT_MAJOR 1)
+set(MCUT_MINOR 2)
+set(MCUT_PATCH 0)
+
+set( MCUT_VERSION "${MCUT_MAJOR}.${MCUT_MINOR}.${MCUT_PATCH}" )
+
+message(STATUS "[MCUT] version: ${MCUT_VERSION}")
+
+set (CMAKE_CXX_STANDARD 11)
+set (CMAKE_CXX_STANDARD_REQUIRED True)
+set (CMAKE_EXPORT_COMPILE_COMMANDS ON)
+
+set (project_API_version_string "${MCUT_VERSION}")
+set (project_build_version_string "${MCUT_VERSION}")
+set (project_namespace_name MCUT)
+
+# Only do these if this is the main project, and not if it is included through add_subdirectory
+if(CMAKE_PROJECT_NAME STREQUAL PROJECT_NAME)
+
+  # Let's ensure -std=c++xx instead of -std=g++xx
+  set(CMAKE_CXX_EXTENSIONS OFF)
+
+  # Let's nicely support folders in IDEs
+  set_property(GLOBAL PROPERTY USE_FOLDERS ON)
+
+  # Testing only available if this is the main app
+  # Note this needs to be done in the main CMakeLists
+  # since it calls enable_testing, which must be in the
+  # main CMakeLists.
+  include(CTest)
+
+  if(MCUT_BUILD_DOCUMENTATION)
+	# Docs only available if this is the main app
+	find_package(Doxygen)
+
+	if(Doxygen_FOUND)
+		add_subdirectory(docs)
+	else()
+		message(STATUS "Doxygen not found, not building docs")
+	endif()
+  endif()
+endif()
+
+include(CMakePrintHelpers) 
+
+#
+# User options
+#
+option(MCUT_BUILD_DOCUMENTATION "Configure to build docs with Doxygen" OFF) # OFF by default
+if (MCUT_TOPLEVEL_PROJECT AND NOT MCUT_BUILD_TESTS)
+	option(MCUT_BUILD_TESTS "Configure to build tests" ON)
+endif()
+option(MCUT_BUILD_AS_SHARED_LIB "Configure to build MCUT as a shared/dynamic library" OFF)
+option(MCUT_BUILD_WITH_COMPUTE_HELPER_THREADPOOL "Configure to build MCUT engine with a shared (amongst contexts) thread-pool" ON)
+if (MCUT_TOPLEVEL_PROJECT AND NOT MCUT_BUILD_TUTORIALS) 
+	option(MCUT_BUILD_TUTORIALS "Configure to build MCUT tutorials" ON)
+endif()
+#
+# machine-precision-numbers library targets
+#
+set (target_name mcut)
+
+#
+# MCUT compilation variables/settings
+#
+set (MCUT_INCLUDE_DIR ${CMAKE_CURRENT_SOURCE_DIR}/include CACHE STRING "The MCUT include directory")
+
+message(STATUS "[MCUT] MCUT_INCLUDE_DIR=${MCUT_INCLUDE_DIR}")
+
+list(APPEND include_dirs  ${MCUT_INCLUDE_DIR})
+list(APPEND compilation_flags "")
+if(MCUT_BUILD_AS_SHARED_LIB)
+	list(APPEND preprocessor_defs -DMCUT_SHARED_LIB=1)
+endif()
+
+find_package(Threads REQUIRED)
+
+list(APPEND extra_libs Threads::Threads) 
+
+if (MCUT_BUILD_WITH_COMPUTE_HELPER_THREADPOOL)
+	list(APPEND preprocessor_defs -DMCUT_WITH_COMPUTE_HELPER_THREADPOOL=1)
+endif()
+
+if ("${CMAKE_CXX_COMPILER_ID}" STREQUAL "Clang" OR "${CMAKE_CXX_COMPILER_ID}" STREQUAL "GNU")
+	list(APPEND compilation_flags -Wall -Wextra)
+elseif ("${CMAKE_CXX_COMPILER_ID}" STREQUAL "Intel")
+	list(APPEND compilation_flags w3 -diag-disable:remark)
+elseif ("${CMAKE_CXX_COMPILER_ID}" STREQUAL "MSVC")
+	list(APPEND compilation_flags /W4 /wd26812 /bigobj)
+	list(APPEND preprocessor_defs -D_CRT_SECURE_NO_WARNINGS)
+endif()
+
+message(STATUS "[MCUT] compilation_flags=${compilation_flags}")
+message(STATUS "[MCUT] preprocessor_defs=${preprocessor_defs}")
+message(STATUS "[MCUT] extra_libs=${extra_libs}")
+
+set (	project_source_files  
+		${CMAKE_CURRENT_SOURCE_DIR}/source/mcut.cpp 
+		${CMAKE_CURRENT_SOURCE_DIR}/source/kernel.cpp 
+		${CMAKE_CURRENT_SOURCE_DIR}/source/hmesh.cpp
+		${CMAKE_CURRENT_SOURCE_DIR}/source/math.cpp
+		${CMAKE_CURRENT_SOURCE_DIR}/source/bvh.cpp
+		${CMAKE_CURRENT_SOURCE_DIR}/source/shewchuk.c
+		${CMAKE_CURRENT_SOURCE_DIR}/source/frontend.cpp
+		${CMAKE_CURRENT_SOURCE_DIR}/source/preproc.cpp)
+
+#
+# Create MCUT target(s)
+#
+
+# This function invokes commands which create a library target (static, shared etc.)
+function(create_library_target LIBRARY_TYPE)
+    message(STATUS "[MCUT] create target: name=${target_name} type=${LIBRARY_TYPE}")
+	
+	add_library(${target_name} ${LIBRARY_TYPE} ${project_source_files})
+
+	target_include_directories(${target_name} PRIVATE ${include_dirs})
+	target_link_libraries(${target_name} PRIVATE ${extra_libs})
+	target_compile_options(${target_name} PRIVATE ${compilation_flags})
+	target_compile_definitions(${target_name} PRIVATE ${preprocessor_defs} )
+	
+	if (MCUT_BUILD_AS_SHARED_LIB AND WIN32)
+		# add macro to export .dll symbols
+		target_compile_definitions(${target_name} PRIVATE -DMCUT_EXPORT_SHARED_LIB_SYMBOLS=1)
+	endif()
+
+	set_property(TARGET ${target_name} PROPERTY VERSION ${project_build_version_string})
+	set_property(TARGET ${target_name} PROPERTY SOVERSION ${project_API_version_string})
+
+	get_target_property(target_type ${target_name} TYPE)
+
+	if ("${target_type}" STREQUAL "SHARED")
+		set_property(TARGET ${target_name} PROPERTY POSITION_INDEPENDENT_CODE ON)
+		if(MSVC)
+			set_property(TARGET ${target_name} PROPERTY WINDOWS_EXPORT_ALL_SYMBOLS ON)
+		endif()
+	endif()
+endfunction()
+
+#
+# create target
+#
+if(MCUT_BUILD_AS_SHARED_LIB)
+	create_library_target(SHARED) 
+else()
+	create_library_target(STATIC)
+endif()
+
+set (MCUT_LIB_PATH $<TARGET_FILE:mcut>  CACHE STRING "Path to the compiled MCUT library file")
+message(STATUS "[MCUT] MCUT_LIB_PATH=${MCUT_LIB_PATH}")
+
+#
+# tests, tutorials etc. are dependant on third-party libs (file loaders etc.)
+# We enable the code that is used to download those projects here:
+#
+if(${MCUT_BUILD_TESTS} OR ${MCUT_BUILD_TUTORIALS})
+
+	# FetchContent added in CMake 3.11, downloads during the configure step
+	include(FetchContent)
+	# FetchContent_MakeAvailable was not added until CMake 3.14; use our shim
+	if(${CMAKE_VERSION} VERSION_LESS 3.14)
+		include(cmake/add_FetchContent_MakeAvailable.cmake)
+	endif()
+
+	FetchContent_Populate(
+		libigl
+		GIT_REPOSITORY 			https://github.com/libigl/libigl.git
+		GIT_TAG       	v2.3.0
+		GIT_PROGRESS TRUE
+	)
+
+	#set(libigl_include_dir ${CMAKE_BINARY_DIR}/libigl-src/include)
+	set(libigl_include_dir ${libigl_SOURCE_DIR}/include)
+
+	set(LIBIGL_EIGEN_VERSION 3.3.7 CACHE STRING "Default version of Eigen used by libigl.")
+
+	# used by tests & tutorials
+	#download_project(PROJ                eigen
+	#				 GIT_REPOSITORY      https://gitlab.com/libeigen/eigen.git
+	#				 GIT_TAG             ${LIBIGL_EIGEN_VERSION}
+	#				 ${UPDATE_DISCONNECTED_IF_AVAILABLE}
+	#)
+	FetchContent_Declare(
+		eigen
+		GIT_REPOSITORY 			https://gitlab.com/libeigen/eigen.git
+		GIT_TAG       	${LIBIGL_EIGEN_VERSION}
+		GIT_SHALLOW TRUE
+  		GIT_PROGRESS TRUE
+	)
+
+	set(EIGEN_BUILD_DOC OFF)
+	# note: To disable eigen tests,
+	# you should put this code in a add_subdirectory to avoid to change
+	# BUILD_TESTING for your own project too since variables are directory
+	# scoped
+	set(BUILD_TESTING OFF)
+	set(EIGEN_BUILD_PKGCONFIG OFF)
+	set( OFF)
+	FetchContent_MakeAvailable(eigen)
+
+	#set(eigen_include_dir ${CMAKE_BINARY_DIR}/eigen-src)
+	set(eigen_include_dir ${eigen_SOURCE_DIR})
+endif()
+
+#
+# tests
+#
+if(MCUT_BUILD_TESTS)
+	add_subdirectory(tests)
+endif()
+
+#
+# tutorials
+#
+if(MCUT_BUILD_TUTORIALS)
+	add_subdirectory(tutorials)
+endif()
+
+#
+# documentation
+#
+if(MCUT_BUILD_DOCUMENTATION)
+	add_subdirectory(docs)
+endif()
+
+########################################################
+###                   PACKAGING                      ###
+### This is a quite INCOMPLETE set of variables that ###
+### should be set for the various generators.        ###
+### Consult the CPack documentations for a full set. ###
+########################################################
+
+# https://gitlab.kitware.com/cmake/community/-/wikis/doc/cpack/Component-Install-With-CPack
+# https://stackoverflow.com/questions/6003374/what-is-cmake-equivalent-of-configure-prefix-dir-make-all-install
+
+# TODO: package documentation files
+
+if(MCUT_BUILD_AS_SHARED_LIB)
+	#
+	# dynamic libs
+	#
+
+	install(TARGETS ${mpn_shared_lib_name}
+			LIBRARY
+			DESTINATION lib/shared
+			COMPONENT dynamic_libraries)
+else()
+	#
+	# static libs
+	#
+	
+	install(TARGETS ${mpn_static_lib_name}
+			ARCHIVE
+			DESTINATION lib/static
+			COMPONENT static_libraries)
+endif()
+
+#
+# headers
+#
+install(FILES ${MCUT_INCLUDE_DIR}/mcut/mcut.h ${MCUT_INCLUDE_DIR}/mcut/platform.h
+  		DESTINATION include/mcut
+	  	COMPONENT headers)
+	  
+install(FILES 
+		${CMAKE_CURRENT_SOURCE_DIR}/LICENSE.txt
+		${CMAKE_CURRENT_SOURCE_DIR}/README.md
+		DESTINATION ./
+		COMPONENT text_files)
+
+#
+# notify CPack of the names of all of the components in the project
+#
+set(CPACK_COMPONENTS_ALL static_libraries dynamic_libraries headers text_files) # applications
+
+set(CPACK_COMPONENT_APPLICATIONS_DISPLAY_NAME "MCUT Application")
+set(CPACK_COMPONENT_STATIC_LIBRARIES_DISPLAY_NAME "Static Libraries")
+set(CPACK_COMPONENT_DYNAMIC_LIBRARIES_DISPLAY_NAME "Dynamics Libraries")
+set(CPACK_COMPONENT_HEADERS_DISPLAY_NAME "C++ Headers")
+
+set(CPACK_COMPONENT_APPLICATIONS_DESCRIPTION
+  "A simple application using MCUT")
+set(CPACK_COMPONENT_STATIC_LIBRARIES_DESCRIPTION
+  "Static libraries used to build programs with MCUT")
+  set(CPACK_COMPONENT_DYNAMIC_LIBRARIES_DESCRIPTION
+  "Dynamic libraries used to build programs with MCUT")
+set(CPACK_COMPONENT_HEADERS_DESCRIPTION
+  "C/C++ header files for use with MCUT")
+
+#  
+# component dependencies
+#
+set(CPACK_COMPONENT_HEADERS_DEPENDS static_libraries dynamic_libraries)
+
+set(CPACK_COMPONENT_APPLICATIONS_GROUP "Runtime")
+set(CPACK_COMPONENT_STATIC_LIBRARIES_GROUP "Development")
+set(CPACK_COMPONENT_DYNAMIC_LIBRARIES_GROUP "Development")
+set(CPACK_COMPONENT_HEADERS_GROUP "Development")
+
+set(CPACK_COMPONENT_GROUP_DEVELOPMENT_DESCRIPTION
+  "All of the tools you'll ever need to develop software")
+
+set (CPACK_PACKAGE_NAME "MCUT")
+set (CPACK_PACKAGE_VENDOR "Floyd M. Chitalu")
+set (CPACK_PACKAGE_DIRECTORY "${CMAKE_CURRENT_BINARY_DIR}")
+set (CPACK_PACKAGE_VERSION_MAJOR "${MCUT_MAJOR}")
+set (CPACK_PACKAGE_VERSION_MINOR "${MCUT_MINOR}")
+set (CPACK_PACKAGE_VERSION_PATCH "${MCUT_PATCH}")
+#set (CPACK_PACKAGE_DESCRIPTION "MCUT (pronounced ‘emcut’) is a tool for cutting meshes.")
+#set (CPACK_PACKAGE_DESCRIPTION_FILE ${CMAKE_CURRENT_SOURCE_DIR}/DESCRIPTION.txt)
+set (CPACK_PACKAGE_DESCRIPTION_SUMMARY "MCUT is a library for cutting meshes to perform tasks like boolean operations and more.")
+set (CPACK_PACKAGE_HOMEPAGE_URL "https://cutdigital.github.io/mcut.site/")
+set (CPACK_PACKAGE_INSTALL_DIRECTORY ${CPACK_PACKAGE_NAME})
+# set (CPACK_PACKAGE_ICON ) 
+set (CPACK_PACKAGE_CHECKSUM SHA256)
+#set (CPACK_PROJECT_CONFIG_FILE ) 
+set (CPACK_RESOURCE_FILE_LICENSE ${CMAKE_CURRENT_SOURCE_DIR}/LICENSE.txt) # must also include in install command
+set (CPACK_RESOURCE_FILE_README ${CMAKE_CURRENT_SOURCE_DIR}/README.md)
+#set (CPACK_RESOURCE_FILE_WELCOME ${CMAKE_CURRENT_SOURCE_DIR}/WELCOME.txt)
+
+if (WIN32)
+    if (USE_WIX_TOOLSET)
+        set(CPACK_GENERATOR "WIX") # this need WiX Tooset installed and a path to candle.exe
+    else ()
+        set(CPACK_GENERATOR "NSIS") # this needs NSIS installed, and available
+    endif ()
+elseif ( ${CMAKE_SYSTEM_NAME} MATCHES "Darwin" )
+    set(CPACK_GENERATOR "PackageMake")
+else ()
+    set(CPACK_GENERATOR "TGZ")
+endif ()
+
+#set (CPACK_OUTPUT_CONFIG_FILE ) # Defaults to CPackConfig.cmake.
+#set (CPACK_PACKAGE_EXECUTABLES ) 
+set (CPACK_STRIP_FILES TRUE)
+# set (CPACK_VERBATIM_VARIABLES )
+# set (CPACK_SOURCE_PACKAGE_FILE_NAME )
+# set (CPACK_SOURCE_STRIP_FILES )
+# set (CPACK_SOURCE_GENERATOR )
+# set (CPACK_SOURCE_OUTPUT_CONFIG_FILE )
+# set (CPACK_SOURCE_IGNORE_FILES )
+# set (CPACK_CMAKE_GENERATOR )
+# set (CPACK_INSTALL_CMAKE_PROJECTS ) 
+# set (CPACK_INSTALL_CMAKE_PROJECTS )
+# set (CPACK_SYSTEM_NAME )
+# set (CPACK_PACKAGE_VERSION )
+# set (CPACK_TOPLEVEL_TAG )
+# set (CPACK_INSTALL_COMMANDS )
+# set (CPACK_INSTALLED_DIRECTORIES )
+# set ( )
+
+
+include(CPack)
+
+# eof

src/mcut/LICENSE.GPL.txt

@@ -0,0 +1,674 @@
+                    GNU GENERAL PUBLIC LICENSE
+                       Version 3, 29 June 2007
+
+ Copyright (C) 2007 Free Software Foundation, Inc. <http://fsf.org/>
+ Everyone is permitted to copy and distribute verbatim copies
+ of this license document, but changing it is not allowed.
+
+                            Preamble
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+
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+
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+permission to link or combine any covered work with a work licensed
+under version 3 of the GNU Affero General Public License into a single
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+but the special requirements of the GNU Affero General Public License,
+section 13, concerning interaction through a network will apply to the
+combination as such.
+
+  14. Revised Versions of this License.
+
+  The Free Software Foundation may publish revised and/or new versions of
+the GNU General Public License from time to time.  Such new versions will
+be similar in spirit to the present version, but may differ in detail to
+address new problems or concerns.
+
+  Each version is given a distinguishing version number.  If the
+Program specifies that a certain numbered version of the GNU General
+Public License "or any later version" applies to it, you have the
+option of following the terms and conditions either of that numbered
+version or of any later version published by the Free Software
+Foundation.  If the Program does not specify a version number of the
+GNU General Public License, you may choose any version ever published
+by the Free Software Foundation.
+
+  If the Program specifies that a proxy can decide which future
+versions of the GNU General Public License can be used, that proxy's
+public statement of acceptance of a version permanently authorizes you
+to choose that version for the Program.
+
+  Later license versions may give you additional or different
+permissions.  However, no additional obligations are imposed on any
+author or copyright holder as a result of your choosing to follow a
+later version.
+
+  15. Disclaimer of Warranty.
+
+  THERE IS NO WARRANTY FOR THE PROGRAM, TO THE EXTENT PERMITTED BY
+APPLICABLE LAW.  EXCEPT WHEN OTHERWISE STATED IN WRITING THE COPYRIGHT
+HOLDERS AND/OR OTHER PARTIES PROVIDE THE PROGRAM "AS IS" WITHOUT WARRANTY
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+  16. Limitation of Liability.
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+EVEN IF SUCH HOLDER OR OTHER PARTY HAS BEEN ADVISED OF THE POSSIBILITY OF
+SUCH DAMAGES.
+
+  17. Interpretation of Sections 15 and 16.
+
+  If the disclaimer of warranty and limitation of liability provided
+above cannot be given local legal effect according to their terms,
+reviewing courts shall apply local law that most closely approximates
+an absolute waiver of all civil liability in connection with the
+Program, unless a warranty or assumption of liability accompanies a
+copy of the Program in return for a fee.
+
+                     END OF TERMS AND CONDITIONS
+
+            How to Apply These Terms to Your New Programs
+
+  If you develop a new program, and you want it to be of the greatest
+possible use to the public, the best way to achieve this is to make it
+free software which everyone can redistribute and change under these terms.
+
+  To do so, attach the following notices to the program.  It is safest
+to attach them to the start of each source file to most effectively
+state the exclusion of warranty; and each file should have at least
+the "copyright" line and a pointer to where the full notice is found.
+
+    <one line to give the program's name and a brief idea of what it does.>
+    Copyright (C) <year>  <name of author>
+
+    This program is free software: you can redistribute it and/or modify
+    it under the terms of the GNU General Public License as published by
+    the Free Software Foundation, either version 3 of the License, or
+    (at your option) any later version.
+
+    This program is distributed in the hope that it will be useful,
+    but WITHOUT ANY WARRANTY; without even the implied warranty of
+    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+    GNU General Public License for more details.
+
+    You should have received a copy of the GNU General Public License
+    along with this program.  If not, see <http://www.gnu.org/licenses/>.
+
+Also add information on how to contact you by electronic and paper mail.
+
+  If the program does terminal interaction, make it output a short
+notice like this when it starts in an interactive mode:
+
+    <program>  Copyright (C) <year>  <name of author>
+    This program comes with ABSOLUTELY NO WARRANTY; for details type `show w'.
+    This is free software, and you are welcome to redistribute it
+    under certain conditions; type `show c' for details.
+
+The hypothetical commands `show w' and `show c' should show the appropriate
+parts of the General Public License.  Of course, your program's commands
+might be different; for a GUI interface, you would use an "about box".
+
+  You should also get your employer (if you work as a programmer) or school,
+if any, to sign a "copyright disclaimer" for the program, if necessary.
+For more information on this, and how to apply and follow the GNU GPL, see
+<http://www.gnu.org/licenses/>.
+
+  The GNU General Public License does not permit incorporating your program
+into proprietary programs.  If your program is a subroutine library, you
+may consider it more useful to permit linking proprietary applications with
+the library.  If this is what you want to do, use the GNU Lesser General
+Public License instead of this License.  But first, please read
+<http://www.gnu.org/philosophy/why-not-lgpl.html>.

src/mcut/LICENSE.txt

@@ -0,0 +1,19 @@
+Permission to use this software is governed by two licensing options which are mutually exclusive:
+
+(A) Open source GNU General Public License ("GPL"); a copy of which you should have recieved. 
+	- see also: <http://www.gnu.org/licenses/>
+	
+(B) Commercial license, which can be purchased from the owner.
+
+    The commercial license option is for users that wish to use MCUT in 
+    their products for comercial purposes but do not wish to release their 
+    software under the GPL. 
+
+    For more information, email "floyd.m.chitalu@gmail.com".
+
+These options protect the project's commercial value and thus make it possible for the 
+author to guarantee long term support, maintenance and further development of the 
+code for the benefit of the project and its users.
+
+This software is also partly based on "CDT" (C++ library for constrained Delaunay triangulation): https://github.com/artem-ogre/CDT
+CDT files that were originally under the MPL-2.0 are dual licensed under the MPL-2.0 and the GNU General Public License (GPL) licenses.

src/mcut/README.md

@@ -0,0 +1,112 @@
+# MCUT Overview
+
+Gist: _A simple and fast C++ library for mesh booleans and more..._ 
+
+[![Windows](https://github.com/cutdigital/mcut/actions/workflows/windows.yml/badge.svg)](https://github.com/cutdigital/mcut/actions/workflows/windows.yml)
+[![MacOS](https://github.com/cutdigital/mcut/actions/workflows/macos.yml/badge.svg)](https://github.com/cutdigital/mcut/actions/workflows/macos.yml) [![Linux](https://github.com/cutdigital/mcut/actions/workflows/linux.yaml/badge.svg)](https://github.com/cutdigital/mcut/actions/workflows/linux.yaml)
+
+This is a software project designed for a broad range of real-world problems relating to 3D modelling and design tasks. Application areas include computer animation, aerospace and automotive engineering, mining, civil and mechanical engineering amongst others. 
+
+The project is called "MCUT" (short for 'mesh cutting'), and it provides functionality to perform fast and robust geometry operations, as shown below:
+
+<p align="center">
+  <img src="https://github.com/cutdigital/mcut.github.io/blob/master/docs/media/repo-teaser/github-teaser.png?raw=true">
+  Figure 1: Generate, slice and perform Booleans without errors.
+</p>
+
+
+The codebase provides a comprehensive tool for ensuring that computer-aided planning tasks for e.g. mine-design, rock strata boring (e.g. underground-tunnel excavations), oil-well drilling and general 3D modelling for animation are achievable with robustness. The tool is developed to take advantage of modern high-performance parallel computing hardware for you, and is demonstrably robust by using precise geometric algorithms that are implemented in C++ and accessed through an intuitive API that resembles the all-familiar C programming language.
+
+Importantly, MCUT is designed with the philosophy that users don't know or don't care about esoteric problems with floating point arithmetic.
+
+# Capabilities
+
+MCUT is a tool for partitioning meshes that represent solids or open surfaces: It is a code library for cutting 3D mesh objects using their geometry to produce crisp fragments at fine scale, which is useful for operations like slicing and boolean operations (union, subtraction and intersection). Supported features include (see images below):
+
+* **Stencilling**: exact cut-outs of the cutting surface
+* **Intersection curve access**: geometry representing lines of intersection-contour points
+* **Partial cuts**: producing valid results where an open-surface is not necessarily completely cutting through a solid.
+* **Concatenation**: merging a solids or open-surfaces with another.
+* **Sectioning**: elimination of material/volume on one side of a specified surface (e.g. a plane) 
+* **Splitting**: partitioning one mesh using another that might be open or solid. 
+* **Cross-platform**: tested on Windows, Linux (Ubuntu), and macOS
+* **Bloat-free**: no external dependencies.
+* **Performant**: continuously profiled, and optimized.
+* **Numerically robust**: Algorithms rely on robust geometric predicates.
+
+What is being offered is a general solution to the problem of resolving solid- and/or open-mesh intersections. It is a solution that is sought by many companies, researchers, and private individuals for its ability to address extremely difficult problems relating to computational geometry in 3D. A classic application is constructive solid geometry (CSG) i.e. the “boolean operation”, which is shown below, where the resulting meshes/objects are produced with MCUT:
+
+<p align="center">
+  <img src="https://github.com/cutdigital/mcut.github.io/blob/master/docs/media/repo-teaser/teaser2.png?raw=true">
+  Figure 2: Generate solids / polygons using a robust Boolean engine, where other technologies fail, MCUT solids will be valid.
+</p>
+
+# Practical benefits and advantages for users
+
+The expert capabilities of MCUT will allow companies, individuals and researchers-alike to develop robust (and fast) Computer-Aided Design (CAD) and Manufacturing (CAM) tools. For example, these tools could cater to the design of industry-specific structural models like tunnels, drill holes, mechanical instruments and rock-block models. All this alongside the ability to handle general 3D modelling tasks that are typical in industry and academic-fields related to computer graphics (e.g. game-engine level design) and mechanical engineering (e.g. fracture simulation). In essence, users of MCUT are provided with the capability to create robust derivative products and tools for generating (and testing) structural designs in a virtual setting for short- and long-term production operations and feasibility tests/studies.
+
+The following images show more examples of what users can achieve with MCUT:
+
+<p align="center">
+  <img src="https://github.com/cutdigital/mcut.github.io/blob/master/docs/media/repo-teaser/extra-images/eg-teaser.jpg?raw=true">
+  Figure 3: Fracture simulation using the Extended Finite Element Method (XFEM) (https://onlinelibrary.wiley.com/doi/abs/10.1111/cgf.13953), where MCUT is used to create fragment geometry by intersecting the simulation domain with propagated cracks.
+</p>
+
+<p align="center">
+  <img src="https://github.com/cutdigital/mcut.github.io/blob/master/docs/media/repo-teaser/extra-images/image156.png?raw=true">
+  Figure 4: Intersecting a gear cog with a surface to model the fracturing of steel.
+</p>
+
+<p align="center">
+  <img src="https://github.com/cutdigital/mcut.github.io/blob/master/docs/media/repo-teaser/extra-images/path1471.png?raw=true">
+  Figure 5: Merging an engine with the axle shaft to model their connectivity.
+</p>
+
+<p align="center">
+  <img src="https://github.com/cutdigital/mcut.github.io/blob/master/docs/media/repo-teaser/extra-images/arm-sphere.png?raw=true">
+  Figure 6: Intersecting a hand model and a sphere, showing how MCUT can also be useful for planning and designing molding processes for e.g. 3D printing.
+</p>
+
+<p align="center">
+  <img src="https://github.com/cutdigital/mcut.github.io/blob/master/docs/media/repo-teaser/extra-images/arma-bunn.png?raw=true">
+  Figure 8: Assorted results produced by intersecting the Stanford bunny model and armadillo.
+</p>
+
+<p align="center">
+  <img src="https://github.com/cutdigital/mcut.github.io/blob/master/docs/media/repo-teaser/extra-images/path1471-2.png?raw=true">
+  Figure 9: Tunnel excavation of a mountainous terrain for modelling underground construction with a boring machine (represented with cylinder). Note how the input meshes need not be solids.
+</p>
+
+<p align="center">
+  <img src="https://github.com/cutdigital/mcut.github.io/blob/master/docs/media/repo-teaser/extra-images/image111.png?raw=true">
+  Figure 10: Creating an Open-Pit mine model on a rough terrain for e.g. pre-planning operations.
+</p>
+
+<p align="center">
+  <img src="https://github.com/cutdigital/mcut.github.io/blob/master/docs/media/repo-teaser/extra-images/path1471-5.png?raw=true">
+  Figure 11: An example of sectioning with a flat plane, which can be used to eliminate material/volume on either side of this plane or create hollow carve-outs.
+</p>
+
+# Source code and test applications
+
+The source code is available for your perusal and evaluation. You can access right here on Github. This is an opportunity for you to trial and experiment with MCUT for your needs. Here is a quick example of how you clone and build the library:
+
+* `git clone https://github.com/cutdigital/mcut.git` 
+* `mkdir build`
+* `cd build`
+* `cmake ..` (see `CMakeLists.txt` for available build configuration options) 
+* run `make -j4` *IF* you are on Linux/MacOS terminal, *ELSE* open the generated `.sln` with e.g. Visual Studio
+
+Next, try out one of the tutorials!
+
+# Licensing
+
+MCUT is available under an Open Source license as well as a commercial license. Users choosing to use MCUT under the free-of-charge Open Source license (e.g. for academic purposes) simply need to comply to its terms, otherwise a commercial license is required. The Open Source license is the "GNU General Public License" (GPL). In cases where the constraints of the Open source license prevent you from using MCUT, a commercial license can be purchased. The library is licensed with an attractively low price which is a one-off sum, requiring no further loyalty fees with guarranteed future updates for free. 
+
+These options protect the project's commercial value and thus make it possible for the author to guarantee long term support, maintenance and further development of the code for the benefit of the project and its users.
+
+---
+
+If MCUT helped you please consider adding a star here on GitHub. This means a lot to the author.
+
+_You can also send an [email](floyd.m.chitalu@gmail.com) to the author if you have questions about MCUT_.

src/mcut/cmake/add_FetchContent_MakeAvailable.cmake

@@ -0,0 +1,7 @@
+macro(FetchContent_MakeAvailable NAME)
+  FetchContent_GetProperties(${NAME})
+  if(NOT ${NAME}_POPULATED)
+    FetchContent_Populate(${NAME})
+    add_subdirectory(${${NAME}_SOURCE_DIR} ${${NAME}_BINARY_DIR})
+  endif()
+endmacro()

src/mcut/include/mcut/internal/bvh.h

@@ -0,0 +1,327 @@
+/**
+ * Copyright (c) 2021-2022 Floyd M. Chitalu.
+ * All rights reserved.
+ *
+ * NOTE: This file is licensed under GPL-3.0-or-later (default).
+ * A commercial license can be purchased from Floyd M. Chitalu.
+ *
+ * License details:
+ *
+ * (A)  GNU General Public License ("GPL"); a copy of which you should have
+ *      recieved with this file.
+ * 	    - see also: <http://www.gnu.org/licenses/>
+ * (B)  Commercial license.
+ *      - email: floyd.m.chitalu@gmail.com
+ *
+ * The commercial license options is for users that wish to use MCUT in
+ * their products for comercial purposes but do not wish to release their
+ * software products under the GPL license.
+ *
+ * Author(s)     : Floyd M. Chitalu
+ */
+#ifndef MCUT_BVH_H_
+#define MCUT_BVH_H_
+
+#include "mcut/internal/hmesh.h"
+#include "mcut/internal/math.h"
+
+#if defined(MCUT_WITH_COMPUTE_HELPER_THREADPOOL)
+#include "mcut/internal/tpool.h"
+#endif
+
+// OIBVH is over 2-3x faster than the alternative (classic) BVH approaches.
+// Our alternative BVH implementations follow: https://www.pbrt.org/chapters/pbrt-2ed-chap4.pdf
+#define USE_OIBVH 1
+
+// Expands a 10-bit integer into 30 bits by inserting 2 zeros after each bit.
+extern unsigned int expandBits(unsigned int v);
+
+// Calculates a 30-bit Morton code for the given 3D point located within the unit cube [0,1].
+extern unsigned int morton3D(float x, float y, float z);
+
+#if defined(USE_OIBVH)
+
+// TODO: just use std::pair
+typedef struct
+{
+    int m_left; // node-A ID (implicit index)
+    int m_right; // node-B ID (implicit index)
+} node_pair_t; // collision tree node
+
+// count leading zeros in 32 bit bitfield
+extern unsigned int clz(unsigned int x);
+
+// next power of two from x
+extern int next_power_of_two(int x);
+
+// check if "x" is a power of two
+extern bool is_power_of_two(int x);
+
+// compute log-base-2 of "x"
+extern int ilog2(unsigned int x);
+
+// compute index (0...N-1) of the leaf level from the number of leaves
+extern int get_leaf_level_from_real_leaf_count(const int t);
+
+// compute tree-level index from implicit index of a node
+extern int get_level_from_implicit_idx(const int bvhNodeImplicitIndex);
+
+// compute previous power of two
+extern unsigned int flp2(unsigned int x);
+
+// compute size of of Oi-BVH give number of triangles
+extern int get_ostensibly_implicit_bvh_size(const int t);
+
+// compute left-most node on a given level
+extern int get_level_leftmost_node(const int node_level);
+
+// compute right-most leaf node in tree
+extern int get_rightmost_real_leaf(const int bvhLeafLevelIndex, const int num_real_leaf_nodes_in_bvh);
+
+// check if node is a "real node"
+extern bool is_real_implicit_tree_node_id(const int bvhNodeImplicitIndex, const int num_real_leaf_nodes_in_bvh);
+
+// get the right most real node on a given tree level
+extern int get_level_rightmost_real_node(
+    const int rightmostRealLeafNodeImplicitIndex,
+    const int bvhLeafLevelIndex,
+    const int ancestorLevelIndex);
+
+// compute implicit index of a node's ancestor
+extern int get_node_ancestor(
+    const int nodeImplicitIndex,
+    const int nodeLevelIndex,
+    const int ancestorLevelIndex);
+
+// calculate linear memory index of a real node
+extern int get_node_mem_index(
+    const int nodeImplicitIndex,
+    const int leftmostImplicitIndexOnNodeLevel,
+    const int bvh_data_base_offset,
+    const int rightmostRealNodeImplicitIndexOnNodeLevel);
+
+extern void build_oibvh(
+#if defined(MCUT_WITH_COMPUTE_HELPER_THREADPOOL)
+    thread_pool& pool,
+#endif
+    const hmesh_t& mesh,
+    std::vector<bounding_box_t<vec3>>& bvhAABBs,
+    std::vector<fd_t>& bvhLeafNodeFaces,
+    std::vector<bounding_box_t<vec3>>& face_bboxes,
+    const double& slightEnlargmentEps = double(0.0));
+
+extern void intersectOIBVHs(
+    std::map<fd_t, std::vector<fd_t>>& ps_face_to_potentially_intersecting_others,
+    const std::vector<bounding_box_t<vec3>>& srcMeshBvhAABBs,
+    const std::vector<fd_t>& srcMeshBvhLeafNodeFaces,
+    const std::vector<bounding_box_t<vec3>>& cutMeshBvhAABBs,
+    const std::vector<fd_t>& cutMeshBvhLeafNodeFaces);
+#else
+typedef bounding_box_t<vec3> BBox;
+static inline BBox Union(const BBox& a, const BBox& b)
+{
+    BBox out = a;
+    out.expand(b);
+    return out;
+}
+
+static inline BBox Union(const BBox& a, const vec3& b)
+{
+    BBox out = a;
+    out.expand(b);
+    return out;
+}
+
+enum class SplitMethod {
+    SPLIT_SAH = 0,
+    SPLIT_MIDDLE = 1,
+    SPLIT_EQUAL_COUNTS = 2,
+};
+
+// For each primitive to be stored in the BVH, we store the centroid
+// of its bounding box, its complete bounding box, and its index in
+// the primitives array
+struct BVHPrimitiveInfo {
+    BVHPrimitiveInfo(int pn, const BBox& b)
+        : primitiveNumber(pn)
+        , bounds(b)
+    {
+        centroid = b.minimum() * (0.5) + b.maximum() * (0.5);
+    }
+
+    int primitiveNumber;
+    vec3 centroid;
+    bounding_box_t<vec3> bounds;
+};
+
+// Each BVHBuildNode represents a node of the BVH. All nodes store a BBox, which stores
+// the bounds of all of the children beneath the node. Each interior node stores pointers to
+// its two children in children. Interior nodes also record the coordinate axis along which
+// primitives were sorted for distribution to their two children; this information is used to
+// improve the performance of the traversal algorithm. Leaf nodes need to record which
+// primitive or primitives are stored in them; the elements of the BVHAccel::primitives
+// array from the offset firstPrimOffset up to but not including firstPrimOffset +
+// nPrimitives are the primitives in the leaf. (Hence the need for reordering the primi-
+// tives array, so that this representation can be used, rather than, for example, storing a
+// variable-sized array of primitive indices at each leaf node.)
+struct BVHBuildNode {
+    // The BVHBuildNode constructor only initializes the children pointers; we’ll distinguish
+    // between leaf and interior nodes by whether their children pointers are NULL or not,
+    // respectively
+    BVHBuildNode()
+    {
+        children[0] = children[1] = NULL;
+    }
+
+    void InitLeaf(uint32_t first, uint32_t n, const BBox& b)
+    {
+        firstPrimOffset = first;
+        nPrimitives = n;
+        bounds = b;
+    }
+
+    // The InitInterior() method requires that the two children nodes already have been cre-
+    // ated, so that their pointers can be passed in. This requirement makes it easy to compute
+    // the bounds of the interior node, since the children bounds are immediately available.
+    void InitInterior(uint32_t axis, std::shared_ptr<BVHBuildNode>& c0, std::shared_ptr<BVHBuildNode>& c1)
+    {
+        children[0] = c0;
+        children[1] = c1;
+        bounds = Union(c0->bounds, c1->bounds);
+        splitAxis = axis;
+        nPrimitives = 0;
+    }
+
+    bounding_box_t<vec3> bounds;
+    std::shared_ptr<BVHBuildNode> children[2];
+    uint32_t splitAxis, firstPrimOffset, nPrimitives;
+};
+
+struct CompareToMid {
+    CompareToMid(int d, double m)
+    {
+        dim = d;
+        mid = m;
+    }
+    int dim;
+    float mid;
+    bool operator()(const BVHPrimitiveInfo& a) const
+    {
+        return a.centroid[dim] < mid;
+    }
+};
+
+struct ComparePoints {
+    ComparePoints(int d) { dim = d; }
+    int dim;
+    bool operator()(const BVHPrimitiveInfo& a,
+        const BVHPrimitiveInfo& b) const
+    {
+        return a.centroid[dim] < b.centroid[dim];
+    }
+};
+
+struct BucketInfo {
+    BucketInfo() { count = 0; }
+    int count;
+    BBox bounds;
+};
+
+struct CompareToBucket {
+    CompareToBucket(int split, int num, int d, const BBox& b)
+        : centroidBounds(b)
+    {
+        splitBucket = split;
+        nBuckets = num;
+        dim = d;
+    }
+
+    // bool operator()(const BVHPrimitiveInfo &p) const;
+    bool operator()(const BVHPrimitiveInfo& p) const
+    {
+        int b = nBuckets * ((p.centroid[dim] - centroidBounds.minimum()[dim]) / (centroidBounds.maximum()[dim] - centroidBounds.minimum()[dim]));
+        if (b == nBuckets)
+            b = nBuckets - 1;
+        return b <= splitBucket;
+    }
+
+    int splitBucket, nBuckets, dim;
+    const BBox& centroidBounds;
+};
+
+// The LinearBVHNode structure stores the information needed to traverse the BVH. In
+// addition to the bounding box for each node, for leaf nodes it stores the offset and
+// primitive count for the primitives in the node. For interior nodes, it stores the offset to
+// the second child as well as which of the coordinate axes the primitives were partitioned
+// along when the hierarchy was built; this information is used in the traversal routine below
+// to try to visit nodes in front-to-back order along the ray.
+struct LinearBVHNode {
+    BBox bounds;
+    union {
+        uint32_t primitivesOffset; // leaf
+        uint32_t secondChildOffset; // interior
+    };
+    uint8_t nPrimitives; // 0 -> interior node
+    uint8_t axis; // interior node: xyz
+    uint8_t pad[2]; // ensure 32 byte total size
+};
+
+class BoundingVolumeHierarchy {
+
+public:
+    BoundingVolumeHierarchy();
+
+    ~BoundingVolumeHierarchy();
+
+    // three stages to BVH construction
+    void buildTree(const hmesh_t& mesh_,
+        const fixed_precision_number_t& enlargementEps_ = fixed_precision_number_t(0.0),
+        uint32_t mp_ = 1,
+        const SplitMethod& sm_ = SplitMethod::SPLIT_MIDDLE);
+
+    const BBox& GetPrimitiveBBox(int primitiveIndex) const;
+
+    uint32_t flattenBVHTree(std::shared_ptr<BVHBuildNode> node, uint32_t* offset);
+
+    // The initial call to recursiveBuild() is given all of the primitives to be stored in
+    // the tree. It returns a pointer to the root of the tree, which is represented with
+    // the BVHBuildNode structure.
+
+    // responsible for returning a BVH for the subset of primitives represented by the range from
+    // buildData[start] up to and including buildData[end-1]
+    std::shared_ptr<BVHBuildNode> recursiveBuild(
+        std::vector<BVHPrimitiveInfo>& buildData,
+        uint32_t start,
+        uint32_t end,
+        uint32_t* totalNodes,
+        std::vector<fd_t>& orderedPrims);
+
+    int GetNodeCount() const;
+
+    const std::shared_ptr<LinearBVHNode>& GetNode(int idx) const;
+
+    const fd_t& GetPrimitive(int index) const;
+
+    static void intersectBVHTrees(
+#if defined(MCUT_WITH_COMPUTE_HELPER_THREADPOOL)
+        thread_pool& scheduler,
+#endif
+        std::map<fd_t, std::vector<fd_t>>& symmetric_intersecting_pairs,
+        const BoundingVolumeHierarchy& bvhA,
+        const BoundingVolumeHierarchy& bvhB,
+        const uint32_t primitiveOffsetA,
+        const uint32_t primitiveOffsetB);
+
+private:
+    const hmesh_t* mesh;
+    int maxPrimsInNode;
+    SplitMethod splitMethod;
+    fixed_precision_number_t enlargementEps; // used to slight enlarge BVH (with bounds of max cut-mesh perturbation magnitude)
+    std::vector<BVHPrimitiveInfo> buildData;
+    std::vector<fd_t> primitives; // ordered primitives
+    std::vector<BBox> primitiveOrderedBBoxes; // unsorted elements correspond to mesh indices
+    std::vector<std::shared_ptr<LinearBVHNode>> nodes;
+};
+#endif // #if defined(USE_OIBVH)
+
+#endif // MCUT_BVH_H_

src/mcut/include/mcut/internal/cdt/LICENSE.txt

@@ -0,0 +1,373 @@
+Mozilla Public License Version 2.0
+==================================
+
+1. Definitions
+--------------
+
+1.1. "Contributor"
+    means each individual or legal entity that creates, contributes to
+    the creation of, or owns Covered Software.
+
+1.2. "Contributor Version"
+    means the combination of the Contributions of others (if any) used
+    by a Contributor and that particular Contributor's Contribution.
+
+1.3. "Contribution"
+    means Covered Software of a particular Contributor.
+
+1.4. "Covered Software"
+    means Source Code Form to which the initial Contributor has attached
+    the notice in Exhibit A, the Executable Form of such Source Code
+    Form, and Modifications of such Source Code Form, in each case
+    including portions thereof.
+
+1.5. "Incompatible With Secondary Licenses"
+    means
+
+    (a) that the initial Contributor has attached the notice described
+        in Exhibit B to the Covered Software; or
+
+    (b) that the Covered Software was made available under the terms of
+        version 1.1 or earlier of the License, but not also under the
+        terms of a Secondary License.
+
+1.6. "Executable Form"
+    means any form of the work other than Source Code Form.
+
+1.7. "Larger Work"
+    means a work that combines Covered Software with other material, in 
+    a separate file or files, that is not Covered Software.
+
+1.8. "License"
+    means this document.
+
+1.9. "Licensable"
+    means having the right to grant, to the maximum extent possible,
+    whether at the time of the initial grant or subsequently, any and
+    all of the rights conveyed by this License.
+
+1.10. "Modifications"
+    means any of the following:
+
+    (a) any file in Source Code Form that results from an addition to,
+        deletion from, or modification of the contents of Covered
+        Software; or
+
+    (b) any new file in Source Code Form that contains any Covered
+        Software.
+
+1.11. "Patent Claims" of a Contributor
+    means any patent claim(s), including without limitation, method,
+    process, and apparatus claims, in any patent Licensable by such
+    Contributor that would be infringed, but for the grant of the
+    License, by the making, using, selling, offering for sale, having
+    made, import, or transfer of either its Contributions or its
+    Contributor Version.
+
+1.12. "Secondary License"
+    means either the GNU General Public License, Version 2.0, the GNU
+    Lesser General Public License, Version 2.1, the GNU Affero General
+    Public License, Version 3.0, or any later versions of those
+    licenses.
+
+1.13. "Source Code Form"
+    means the form of the work preferred for making modifications.
+
+1.14. "You" (or "Your")
+    means an individual or a legal entity exercising rights under this
+    License. For legal entities, "You" includes any entity that
+    controls, is controlled by, or is under common control with You. For
+    purposes of this definition, "control" means (a) the power, direct
+    or indirect, to cause the direction or management of such entity,
+    whether by contract or otherwise, or (b) ownership of more than
+    fifty percent (50%) of the outstanding shares or beneficial
+    ownership of such entity.
+
+2. License Grants and Conditions
+--------------------------------
+
+2.1. Grants
+
+Each Contributor hereby grants You a world-wide, royalty-free,
+non-exclusive license:
+
+(a) under intellectual property rights (other than patent or trademark)
+    Licensable by such Contributor to use, reproduce, make available,
+    modify, display, perform, distribute, and otherwise exploit its
+    Contributions, either on an unmodified basis, with Modifications, or
+    as part of a Larger Work; and
+
+(b) under Patent Claims of such Contributor to make, use, sell, offer
+    for sale, have made, import, and otherwise transfer either its
+    Contributions or its Contributor Version.
+
+2.2. Effective Date
+
+The licenses granted in Section 2.1 with respect to any Contribution
+become effective for each Contribution on the date the Contributor first
+distributes such Contribution.
+
+2.3. Limitations on Grant Scope
+
+The licenses granted in this Section 2 are the only rights granted under
+this License. No additional rights or licenses will be implied from the
+distribution or licensing of Covered Software under this License.
+Notwithstanding Section 2.1(b) above, no patent license is granted by a
+Contributor:
+
+(a) for any code that a Contributor has removed from Covered Software;
+    or
+
+(b) for infringements caused by: (i) Your and any other third party's
+    modifications of Covered Software, or (ii) the combination of its
+    Contributions with other software (except as part of its Contributor
+    Version); or
+
+(c) under Patent Claims infringed by Covered Software in the absence of
+    its Contributions.
+
+This License does not grant any rights in the trademarks, service marks,
+or logos of any Contributor (except as may be necessary to comply with
+the notice requirements in Section 3.4).
+
+2.4. Subsequent Licenses
+
+No Contributor makes additional grants as a result of Your choice to
+distribute the Covered Software under a subsequent version of this
+License (see Section 10.2) or under the terms of a Secondary License (if
+permitted under the terms of Section 3.3).
+
+2.5. Representation
+
+Each Contributor represents that the Contributor believes its
+Contributions are its original creation(s) or it has sufficient rights
+to grant the rights to its Contributions conveyed by this License.
+
+2.6. Fair Use
+
+This License is not intended to limit any rights You have under
+applicable copyright doctrines of fair use, fair dealing, or other
+equivalents.
+
+2.7. Conditions
+
+Sections 3.1, 3.2, 3.3, and 3.4 are conditions of the licenses granted
+in Section 2.1.
+
+3. Responsibilities
+-------------------
+
+3.1. Distribution of Source Form
+
+All distribution of Covered Software in Source Code Form, including any
+Modifications that You create or to which You contribute, must be under
+the terms of this License. You must inform recipients that the Source
+Code Form of the Covered Software is governed by the terms of this
+License, and how they can obtain a copy of this License. You may not
+attempt to alter or restrict the recipients' rights in the Source Code
+Form.
+
+3.2. Distribution of Executable Form
+
+If You distribute Covered Software in Executable Form then:
+
+(a) such Covered Software must also be made available in Source Code
+    Form, as described in Section 3.1, and You must inform recipients of
+    the Executable Form how they can obtain a copy of such Source Code
+    Form by reasonable means in a timely manner, at a charge no more
+    than the cost of distribution to the recipient; and
+
+(b) You may distribute such Executable Form under the terms of this
+    License, or sublicense it under different terms, provided that the
+    license for the Executable Form does not attempt to limit or alter
+    the recipients' rights in the Source Code Form under this License.
+
+3.3. Distribution of a Larger Work
+
+You may create and distribute a Larger Work under terms of Your choice,
+provided that You also comply with the requirements of this License for
+the Covered Software. If the Larger Work is a combination of Covered
+Software with a work governed by one or more Secondary Licenses, and the
+Covered Software is not Incompatible With Secondary Licenses, this
+License permits You to additionally distribute such Covered Software
+under the terms of such Secondary License(s), so that the recipient of
+the Larger Work may, at their option, further distribute the Covered
+Software under the terms of either this License or such Secondary
+License(s).
+
+3.4. Notices
+
+You may not remove or alter the substance of any license notices
+(including copyright notices, patent notices, disclaimers of warranty,
+or limitations of liability) contained within the Source Code Form of
+the Covered Software, except that You may alter any license notices to
+the extent required to remedy known factual inaccuracies.
+
+3.5. Application of Additional Terms
+
+You may choose to offer, and to charge a fee for, warranty, support,
+indemnity or liability obligations to one or more recipients of Covered
+Software. However, You may do so only on Your own behalf, and not on
+behalf of any Contributor. You must make it absolutely clear that any
+such warranty, support, indemnity, or liability obligation is offered by
+You alone, and You hereby agree to indemnify every Contributor for any
+liability incurred by such Contributor as a result of warranty, support,
+indemnity or liability terms You offer. You may include additional
+disclaimers of warranty and limitations of liability specific to any
+jurisdiction.
+
+4. Inability to Comply Due to Statute or Regulation
+---------------------------------------------------
+
+If it is impossible for You to comply with any of the terms of this
+License with respect to some or all of the Covered Software due to
+statute, judicial order, or regulation then You must: (a) comply with
+the terms of this License to the maximum extent possible; and (b)
+describe the limitations and the code they affect. Such description must
+be placed in a text file included with all distributions of the Covered
+Software under this License. Except to the extent prohibited by statute
+or regulation, such description must be sufficiently detailed for a
+recipient of ordinary skill to be able to understand it.
+
+5. Termination
+--------------
+
+5.1. The rights granted under this License will terminate automatically
+if You fail to comply with any of its terms. However, if You become
+compliant, then the rights granted under this License from a particular
+Contributor are reinstated (a) provisionally, unless and until such
+Contributor explicitly and finally terminates Your grants, and (b) on an
+ongoing basis, if such Contributor fails to notify You of the
+non-compliance by some reasonable means prior to 60 days after You have
+come back into compliance. Moreover, Your grants from a particular
+Contributor are reinstated on an ongoing basis if such Contributor
+notifies You of the non-compliance by some reasonable means, this is the
+first time You have received notice of non-compliance with this License
+from such Contributor, and You become compliant prior to 30 days after
+Your receipt of the notice.
+
+5.2. If You initiate litigation against any entity by asserting a patent
+infringement claim (excluding declaratory judgment actions,
+counter-claims, and cross-claims) alleging that a Contributor Version
+directly or indirectly infringes any patent, then the rights granted to
+You by any and all Contributors for the Covered Software under Section
+2.1 of this License shall terminate.
+
+5.3. In the event of termination under Sections 5.1 or 5.2 above, all
+end user license agreements (excluding distributors and resellers) which
+have been validly granted by You or Your distributors under this License
+prior to termination shall survive termination.
+
+************************************************************************
+*                                                                      *
+*  6. Disclaimer of Warranty                                           *
+*  -------------------------                                           *
+*                                                                      *
+*  Covered Software is provided under this License on an "as is"       *
+*  basis, without warranty of any kind, either expressed, implied, or  *
+*  statutory, including, without limitation, warranties that the       *
+*  Covered Software is free of defects, merchantable, fit for a        *
+*  particular purpose or non-infringing. The entire risk as to the     *
+*  quality and performance of the Covered Software is with You.        *
+*  Should any Covered Software prove defective in any respect, You     *
+*  (not any Contributor) assume the cost of any necessary servicing,   *
+*  repair, or correction. This disclaimer of warranty constitutes an   *
+*  essential part of this License. No use of any Covered Software is   *
+*  authorized under this License except under this disclaimer.         *
+*                                                                      *
+************************************************************************
+
+************************************************************************
+*                                                                      *
+*  7. Limitation of Liability                                          *
+*  --------------------------                                          *
+*                                                                      *
+*  Under no circumstances and under no legal theory, whether tort      *
+*  (including negligence), contract, or otherwise, shall any           *
+*  Contributor, or anyone who distributes Covered Software as          *
+*  permitted above, be liable to You for any direct, indirect,         *
+*  special, incidental, or consequential damages of any character      *
+*  including, without limitation, damages for lost profits, loss of    *
+*  goodwill, work stoppage, computer failure or malfunction, or any    *
+*  and all other commercial damages or losses, even if such party      *
+*  shall have been informed of the possibility of such damages. This   *
+*  limitation of liability shall not apply to liability for death or   *
+*  personal injury resulting from such party's negligence to the       *
+*  extent applicable law prohibits such limitation. Some               *
+*  jurisdictions do not allow the exclusion or limitation of           *
+*  incidental or consequential damages, so this exclusion and          *
+*  limitation may not apply to You.                                    *
+*                                                                      *
+************************************************************************
+
+8. Litigation
+-------------
+
+Any litigation relating to this License may be brought only in the
+courts of a jurisdiction where the defendant maintains its principal
+place of business and such litigation shall be governed by laws of that
+jurisdiction, without reference to its conflict-of-law provisions.
+Nothing in this Section shall prevent a party's ability to bring
+cross-claims or counter-claims.
+
+9. Miscellaneous
+----------------
+
+This License represents the complete agreement concerning the subject
+matter hereof. If any provision of this License is held to be
+unenforceable, such provision shall be reformed only to the extent
+necessary to make it enforceable. Any law or regulation which provides
+that the language of a contract shall be construed against the drafter
+shall not be used to construe this License against a Contributor.
+
+10. Versions of the License
+---------------------------
+
+10.1. New Versions
+
+Mozilla Foundation is the license steward. Except as provided in Section
+10.3, no one other than the license steward has the right to modify or
+publish new versions of this License. Each version will be given a
+distinguishing version number.
+
+10.2. Effect of New Versions
+
+You may distribute the Covered Software under the terms of the version
+of the License under which You originally received the Covered Software,
+or under the terms of any subsequent version published by the license
+steward.
+
+10.3. Modified Versions
+
+If you create software not governed by this License, and you want to
+create a new license for such software, you may create and use a
+modified version of this License if you rename the license and remove
+any references to the name of the license steward (except to note that
+such modified license differs from this License).
+
+10.4. Distributing Source Code Form that is Incompatible With Secondary
+Licenses
+
+If You choose to distribute Source Code Form that is Incompatible With
+Secondary Licenses under the terms of this version of the License, the
+notice described in Exhibit B of this License must be attached.
+
+Exhibit A - Source Code Form License Notice
+-------------------------------------------
+
+  This Source Code Form is subject to the terms of the Mozilla Public
+  License, v. 2.0. If a copy of the MPL was not distributed with this
+  file, You can obtain one at http://mozilla.org/MPL/2.0/.
+
+If it is not possible or desirable to put the notice in a particular
+file, then You may include the notice in a location (such as a LICENSE
+file in a relevant directory) where a recipient would be likely to look
+for such a notice.
+
+You may add additional accurate notices of copyright ownership.
+
+Exhibit B - "Incompatible With Secondary Licenses" Notice
+---------------------------------------------------------
+
+  This Source Code Form is "Incompatible With Secondary Licenses", as
+  defined by the Mozilla Public License, v. 2.0.

src/mcut/include/mcut/internal/cdt/cdt.h

@@ -0,0 +1,555 @@
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at https://mozilla.org/MPL/2.0/. */
+
+#ifndef _CONSTRAINED_DELAUNAY_TRIANGULATION_H_
+#define _CONSTRAINED_DELAUNAY_TRIANGULATION_H_
+
+#include "mcut/internal/cdt/triangulate.h"
+#include "mcut/internal/cdt/utils.h"
+
+#include <algorithm>
+#include <cassert>
+#include <cstdlib>
+#include <iterator>
+#include <memory>
+#include <stack>
+#include <vector>
+
+/// Namespace containing triangulation functionality
+namespace cdt {
+
+/** @defgroup API Public API
+ *  Contains API for constrained and conforming Delaunay triangulations
+ */
+/// @{
+
+/**
+ * Type used for storing layer depths for triangles
+ * @note layer_depth_t should support 60K+ layers, which could be to much or
+ * too little for some use cases. Feel free to re-define this typedef.
+ */
+typedef unsigned short layer_depth_t;
+typedef layer_depth_t boundary_overlap_count_t;
+
+/** @defgroup helpers Helpers
+ *  Helpers for working with cdt::triangulator_t.
+ */
+/// @{
+
+/**
+ * Calculate triangles adjacent to vertices (triangles by vertex index)
+ * @param triangles triangulation
+ * @param verticesSize total number of vertices to pre-allocate the output
+ * @return triangles by vertex index (array of size V, where V is the number of vertices; each element is a list of triangles incident to corresponding vertex).
+ */
+inline std::vector<std::vector<std::uint32_t>> get_vertex_to_triangles_map(
+    const std::vector<triangle_t>& triangles,
+    const std::uint32_t verticesSize)
+{
+    std::vector<std::vector<std::uint32_t>> map(verticesSize);
+
+    for (std::uint32_t i = 0; i < (std::uint32_t)triangles.size(); ++i) {
+
+        const std::uint32_t triangle_index = i;
+        const triangle_t& triangle = triangles[triangle_index];
+        const std::array<std::uint32_t, 3>& vertices = triangle.vertices;
+
+        for (std::array<std::uint32_t, 3>::const_iterator j = vertices.begin(); j != vertices.end(); ++j) {
+            const std::uint32_t vertex_index = *j;
+            map[vertex_index].push_back(i);
+        }
+    }
+
+    return map;
+}
+
+/**
+ * Information about removed duplicated vertices.
+ *
+ * Contains mapping information and removed duplicates indices.
+ * @note vertices {0,1,2,3,4} where 0 and 3 are the same will produce mapping
+ *       {0,1,2,0,3} (to new vertices {0,1,2,3}) and duplicates {3}
+ */
+struct duplicates_info_t {
+    std::vector<std::size_t> mapping; ///< vertex index mapping
+    std::vector<std::size_t> duplicates; ///< duplicates' indices
+};
+
+/*!
+ * Remove elements in the range [first; last) with indices from the sorted
+ * unique range [ii_first, ii_last)
+ */
+template <class ForwardIt, class SortUniqIndsFwdIt>
+inline ForwardIt remove_at(
+    ForwardIt first,
+    ForwardIt last,
+    SortUniqIndsFwdIt ii_first,
+    SortUniqIndsFwdIt ii_last)
+{
+    if (ii_first == ii_last) // no indices-to-remove are given
+        return last;
+
+    typedef typename std::iterator_traits<ForwardIt>::difference_type diff_t;
+    typedef typename std::iterator_traits<SortUniqIndsFwdIt>::value_type ind_t;
+
+    ForwardIt destination = first + static_cast<diff_t>(*ii_first);
+
+    while (ii_first != ii_last) {
+
+        // advance to an index after a chunk of elements-to-keep
+        for (ind_t cur = *ii_first++; ii_first != ii_last; ++ii_first) {
+            const ind_t nxt = *ii_first;
+            if (nxt - cur > 1)
+                break;
+            cur = nxt;
+        }
+
+        // move the chunk of elements-to-keep to new destination
+        const ForwardIt source_first = first + static_cast<diff_t>(*(ii_first - 1)) + 1;
+        const ForwardIt source_last = ii_first != ii_last ? first + static_cast<diff_t>(*ii_first) : last;
+
+        std::move(source_first, source_last, destination);
+
+        destination += source_last - source_first;
+    }
+    return destination;
+}
+
+/**
+ * Find duplicates in given custom point-type range
+ * @note duplicates are points with exactly same X and Y coordinates
+ * @tparam TVertexIter iterator that dereferences to custom point type
+ * @tparam TGetVertexCoordX function object getting x coordinate from vertex.
+ * Getter signature: const TVertexIter::value_type& -> T
+ * @tparam TGetVertexCoordY function object getting y coordinate from vertex.
+ * Getter signature: const TVertexIter::value_type& -> T
+ * @param first beginning of the range of vertices
+ * @param last end of the range of vertices
+ * @param get_x_coord getter of X-coordinate
+ * @param get_y_coord getter of Y-coordinate
+ * @returns information about vertex duplicates
+ */
+template <
+    typename T,
+    typename TVertexIter,
+    typename TGetVertexCoordX,
+    typename TGetVertexCoordY>
+duplicates_info_t find_duplicates(
+    TVertexIter first,
+    TVertexIter last,
+    TGetVertexCoordX get_x_coord,
+    TGetVertexCoordY get_y_coord)
+{
+    std::unordered_map<vec2_<T>, std::size_t> uniqueVerts; // position to index map
+    const std::size_t verticesSize = std::distance(first, last);
+
+    duplicates_info_t di = {
+        std::vector<std::size_t>(verticesSize),
+        std::vector<std::size_t>()
+    };
+
+    for (std::size_t iIn = 0, iOut = iIn; iIn < verticesSize; ++iIn, ++first) {
+        typename std::unordered_map<vec2_<T>, std::size_t>::const_iterator it;
+        bool isUnique;
+
+        // check if the coordinates match [exactly] (in the bitwise sense)
+        std::tie(it, isUnique) = uniqueVerts.insert(
+            std::make_pair(
+                vec2_<T>::make(get_x_coord(*first), get_y_coord(*first)),
+                iOut));
+
+        if (isUnique) {
+            di.mapping[iIn] = iOut++;
+            continue;
+        }
+
+        di.mapping[iIn] = it->second; // found a duplicate
+        di.duplicates.push_back(iIn);
+    }
+
+    return di;
+}
+
+/**
+ * Remove duplicates in-place from vector of custom points
+ * @tparam TVertex vertex type
+ * @tparam TAllocator allocator used by input vector of vertices
+ * @param vertices vertices to remove duplicates from
+ * @param duplicates information about duplicates
+ */
+template <typename TVertex, typename TAllocator>
+void remove_duplicates(
+    std::vector<TVertex, TAllocator>& vertices,
+    const std::vector<std::size_t>& duplicates)
+{
+    vertices.erase(
+        remove_at(
+            vertices.begin(),
+            vertices.end(),
+            duplicates.begin(),
+            duplicates.end()),
+        vertices.end());
+}
+
+/**
+ * Remove duplicated points in-place
+ *
+ * @tparam T type of vertex coordinates (e.g., float, double)
+ * @param[in, out] vertices collection of vertices to remove duplicates from
+ * @returns information about duplicated vertices that were removed.
+ */
+template <typename T>
+duplicates_info_t remove_duplicates(std::vector<vec2_<T>>& vertices)
+{
+    const duplicates_info_t di = find_duplicates<T>(
+        vertices.begin(),
+        vertices.end(),
+        get_x_coord_vec2d<T>,
+        get_y_coord_vec2d<T>);
+
+    remove_duplicates(vertices, di.duplicates);
+
+    return di;
+}
+
+/**
+ * Remap vertex indices in edges (in-place) using given vertex-index mapping.
+ * @tparam TEdgeIter iterator that dereferences to custom edge type
+ * @tparam TGetEdgeVertexStart function object getting start vertex index
+ * from an edge.
+ * Getter signature: const TEdgeIter::value_type& -> std::uint32_t
+ * @tparam TGetEdgeVertexEnd function object getting end vertex index from
+ * an edge. Getter signature: const TEdgeIter::value_type& -> std::uint32_t
+ * @tparam TMakeEdgeFromStartAndEnd function object that makes new edge from
+ * start and end vertices
+ * @param first beginning of the range of edges
+ * @param last end of the range of edges
+ * @param mapping vertex-index mapping
+ * @param getStart getter of edge start vertex index
+ * @param getEnd getter of edge end vertex index
+ * @param makeEdge factory for making edge from vetices
+ */
+
+template <
+    typename TEdgeIter,
+    typename TGetEdgeVertexStart,
+    typename TGetEdgeVertexEnd,
+    typename TMakeEdgeFromStartAndEnd>
+void remap_edges(
+    TEdgeIter first,
+    const TEdgeIter last,
+    const std::vector<std::size_t>& mapping,
+    TGetEdgeVertexStart getStart,
+    TGetEdgeVertexEnd getEnd,
+    TMakeEdgeFromStartAndEnd makeEdge)
+{
+    for (; first != last; ++first) {
+        *first = makeEdge(
+            static_cast<std::uint32_t>(mapping[getStart(*first)]),
+            static_cast<std::uint32_t>(mapping[getEnd(*first)]));
+    }
+}
+
+/**
+ * Remap vertex indices in edges (in-place) using given vertex-index mapping.
+ *
+ * @note Mapping can be a result of remove_duplicates function
+ * @param[in,out] edges collection of edges to remap
+ * @param mapping vertex-index mapping
+ */
+inline void
+remap_edges(std::vector<edge_t>& edges, const std::vector<std::size_t>& mapping)
+{
+    remap_edges(
+        edges.begin(),
+        edges.end(),
+        mapping,
+        edge_get_v1,
+        edge_get_v2,
+        edge_make);
+}
+
+/**
+ * Find point duplicates, remove them from vector (in-place) and remap edges
+ * (in-place)
+ * @note Same as a chained call of cdt::find_duplicates, cdt::remove_duplicates,
+ * and cdt::remap_edges
+ * @tparam T type of vertex coordinates (e.g., float, double)
+ * @tparam TVertex type of vertex
+ * @tparam TGetVertexCoordX function object getting x coordinate from vertex.
+ * Getter signature: const TVertexIter::value_type& -> T
+ * @tparam TGetVertexCoordY function object getting y coordinate from vertex.
+ * Getter signature: const TVertexIter::value_type& -> T
+ * @tparam TEdgeIter iterator that dereferences to custom edge type
+ * @tparam TGetEdgeVertexStart function object getting start vertex index
+ * from an edge.
+ * Getter signature: const TEdgeIter::value_type& -> std::uint32_t
+ * @tparam TGetEdgeVertexEnd function object getting end vertex index from
+ * an edge. Getter signature: const TEdgeIter::value_type& -> std::uint32_t
+ * @tparam TMakeEdgeFromStartAndEnd function object that makes new edge from
+ * start and end vertices
+ * @param[in, out] vertices vertices to remove duplicates from
+ * @param[in, out] edges collection of edges connecting vertices
+ * @param get_x_coord getter of X-coordinate
+ * @param get_y_coord getter of Y-coordinate
+ * @param edgesFirst beginning of the range of edges
+ * @param edgesLast end of the range of edges
+ * @param getStart getter of edge start vertex index
+ * @param getEnd getter of edge end vertex index
+ * @param makeEdge factory for making edge from vetices
+ * @returns information about vertex duplicates
+ */
+
+template <
+    typename T,
+    typename TVertex,
+    typename TGetVertexCoordX,
+    typename TGetVertexCoordY,
+    typename TVertexAllocator,
+    typename TEdgeIter,
+    typename TGetEdgeVertexStart,
+    typename TGetEdgeVertexEnd,
+    typename TMakeEdgeFromStartAndEnd>
+duplicates_info_t remove_duplicates_and_remap_edges(
+    std::vector<TVertex, TVertexAllocator>& vertices,
+    TGetVertexCoordX get_x_coord,
+    TGetVertexCoordY get_y_coord,
+    const TEdgeIter edgesFirst,
+    const TEdgeIter edgesLast,
+    TGetEdgeVertexStart getStart,
+    TGetEdgeVertexEnd getEnd,
+    TMakeEdgeFromStartAndEnd makeEdge)
+{
+    const duplicates_info_t di = find_duplicates<T>(vertices.begin(), vertices.end(), get_x_coord, get_y_coord);
+
+    remove_duplicates(vertices, di.duplicates);
+    remap_edges(edgesFirst, edgesLast, di.mapping, getStart, getEnd, makeEdge);
+
+    return di;
+}
+
+/**
+ * Same as a chained call of cdt::remove_duplicates + cdt::remap_edges
+ *
+ * @tparam T type of vertex coordinates (e.g., float, double)
+ * @param[in, out] vertices collection of vertices to remove duplicates from
+ * @param[in,out] edges collection of edges to remap
+ */
+template <typename T>
+duplicates_info_t remove_duplicates_and_remap_edges(
+    std::vector<vec2_<T>>& vertices,
+    std::vector<edge_t>& edges)
+{
+    return remove_duplicates_and_remap_edges<T>(
+        vertices,
+        get_x_coord_vec2d<T>,
+        get_y_coord_vec2d<T>,
+        edges.begin(),
+        edges.end(),
+        edge_get_v1,
+        edge_get_v2,
+        edge_make);
+}
+
+/**
+ * Extract all edges of triangles
+ *
+ * @param triangles triangles used to extract edges
+ * @return an unordered set of all edges of triangulation
+ */
+inline std::unordered_set<edge_t>
+extract_edges_from_triangles(const std::vector<triangle_t>& triangles)
+{
+    std::unordered_set<edge_t> edges;
+
+    for (std::vector<triangle_t>::const_iterator t = triangles.begin(); t != triangles.end(); ++t) {
+        edges.insert(edge_t(std::uint32_t(t->vertices[0]), std::uint32_t(t->vertices[1])));
+        edges.insert(edge_t(std::uint32_t(t->vertices[1]), std::uint32_t(t->vertices[2])));
+        edges.insert(edge_t(std::uint32_t(t->vertices[2]), std::uint32_t(t->vertices[0])));
+    }
+    return edges;
+}
+
+/*!
+ * Converts piece->original_edges mapping to original_edge->pieces
+ * @param pieceToOriginals maps pieces to original edges
+ * @return mapping of original edges to pieces
+ */
+inline std::unordered_map<edge_t, std::vector<edge_t>>
+edge_to_pieces_mapping(const std::unordered_map<edge_t, std::vector<edge_t>>& pieceToOriginals)
+{
+    std::unordered_map<edge_t, std::vector<edge_t>> originalToPieces;
+    typedef std::unordered_map<edge_t, std::vector<edge_t>>::const_iterator Cit;
+    for (Cit ptoIt = pieceToOriginals.begin(); ptoIt != pieceToOriginals.end();
+         ++ptoIt) {
+        const edge_t piece = ptoIt->first;
+        const std::vector<edge_t>& originals = ptoIt->second;
+        for (std::vector<edge_t>::const_iterator origIt = originals.begin();
+             origIt != originals.end();
+             ++origIt) {
+            originalToPieces[*origIt].push_back(piece);
+        }
+    }
+    return originalToPieces;
+}
+
+/*!
+ * Convert edge-to-pieces mapping into edge-to-split-vertices mapping
+ * @tparam T type of vertex coordinates (e.g., float, double)
+ * @param edgeToPieces edge-to-pieces mapping
+ * @param vertices vertex buffer
+ * @return mapping of edge-to-split-points.
+ * Split points are sorted from edge's start (v1) to end (v2)
+ */
+
+template <typename T>
+std::unordered_map<edge_t, std::vector<std::uint32_t>> get_edge_to_split_vertices_map(
+    const std::unordered_map<edge_t, std::vector<edge_t>>& edgeToPieces,
+    const std::vector<vec2_<T>>& vertices)
+{
+    typedef std::pair<std::uint32_t, T> VertCoordPair;
+
+    struct ComparePred {
+        bool operator()(const VertCoordPair& a, const VertCoordPair& b) const
+        {
+            return a.second < b.second;
+        }
+    } comparePred;
+
+    std::unordered_map<edge_t, std::vector<std::uint32_t>> edgeToSplitVerts;
+    
+    for (std::unordered_map<edge_t, std::vector<edge_t>>::const_iterator it = edgeToPieces.begin();
+         it != edgeToPieces.end();
+         ++it) {
+
+        const edge_t& e = it->first;
+        const T dX = vertices[e.v2()].x() - vertices[e.v1()].x();
+        const T dY = vertices[e.v2()].y() - vertices[e.v1()].y();
+        const bool isX = std::abs(dX) >= std::abs(dY); // X-coord longer
+        const bool isAscending = isX ? dX >= 0 : dY >= 0; // Longer coordinate ascends
+        const std::vector<edge_t>& pieces = it->second;
+
+        std::vector<VertCoordPair> splitVerts;
+        // size is:  2[ends] + (pieces - 1)[split vertices] = pieces + 1
+        splitVerts.reserve(pieces.size() + 1);
+
+        for (std::vector<edge_t>::const_iterator it = pieces.begin(); it != pieces.end(); ++it) {
+
+            const std::array<std::uint32_t, 2> vv = { it->v1(), it->v2() };
+
+            for (std::array<std::uint32_t, 2>::const_iterator v = vv.begin(); v != vv.end(); ++v) {
+                const T c = isX ? vertices[*v].x() : vertices[*v].y();
+                splitVerts.push_back(std::make_pair(*v, isAscending ? c : -c));
+            }
+        }
+
+        // sort by longest coordinate
+        std::sort(splitVerts.begin(), splitVerts.end(), comparePred);
+
+        // remove duplicates
+        splitVerts.erase(
+            std::unique(splitVerts.begin(), splitVerts.end()),
+            splitVerts.end());
+
+        MCUT_ASSERT(splitVerts.size() > 2); // 2 end points with split vertices
+
+        std::pair<edge_t, std::vector<std::uint32_t>> val = std::make_pair(e, std::vector<std::uint32_t>());
+
+        val.second.reserve(splitVerts.size());
+
+        for (typename std::vector<VertCoordPair>::const_iterator it = splitVerts.begin() + 1;
+             it != splitVerts.end() - 1;
+             ++it) {
+            val.second.push_back(it->first);
+        }
+
+        edgeToSplitVerts.insert(val);
+    }
+    return edgeToSplitVerts;
+}
+
+/// @}
+
+/// @}
+
+} // namespace cdt
+
+//*****************************************************************************
+// Implementations of template functionlity
+//*****************************************************************************
+// hash for vec2_<T>
+namespace std {
+
+template <typename T>
+struct hash<vec2_<T>> {
+    size_t operator()(const vec2_<T>& xy) const
+    {
+        return std::hash<T>()(xy.x()) ^ std::hash<T>()(xy.y());
+    }
+};
+
+} // namespace std
+
+namespace cdt {
+
+//-----
+// API
+//-----
+
+/**
+ * Verify that triangulation topology is consistent.
+ *
+ * Checks:
+ *  - for each vertex adjacent triangles contain the vertex
+ *  - each triangle's neighbor in turn has triangle as its neighbor
+ *  - each of triangle's vertices has triangle as adjacent
+ *
+ * @tparam T type of vertex coordinates (e.g., float, double)
+ * @tparam TNearPointLocator class providing locating near point for efficiently
+ */
+template <typename T, typename TNearPointLocator>
+inline bool check_topology(const cdt::triangulator_t<T, TNearPointLocator>& cdt)
+{
+    // Check if vertices' adjacent triangles contain vertex
+    const std::vector<std::vector<std::uint32_t>> vertTris = cdt.is_finalized()
+        ? get_vertex_to_triangles_map(
+            cdt.triangles, static_cast<std::uint32_t>(cdt.vertices.size()))
+        : cdt.vertTris;
+    for (std::uint32_t iV(0); iV < std::uint32_t(cdt.vertices.size()); ++iV) {
+        const std::vector<std::uint32_t>& vTris = vertTris[iV];
+        typedef std::vector<std::uint32_t>::const_iterator TriIndCit;
+        for (TriIndCit it = vTris.begin(); it != vTris.end(); ++it) {
+            const std::array<std::uint32_t, 3>& vv = cdt.triangles[*it].vertices;
+            if (std::find(vv.begin(), vv.end(), iV) == vv.end())
+                return false;
+        }
+    }
+    // Check if triangle neighbor links are fine
+    for (std::uint32_t iT(0); iT < std::uint32_t(cdt.triangles.size()); ++iT) {
+        const triangle_t& t = cdt.triangles[iT];
+        typedef std::array<std::uint32_t, 3>::const_iterator NCit;
+        for (NCit it = t.neighbors.begin(); it != t.neighbors.end(); ++it) {
+            if (*it == null_neighbour)
+                continue;
+            const std::array<std::uint32_t, 3>& nn = cdt.triangles[*it].neighbors;
+            if (std::find(nn.begin(), nn.end(), iT) == nn.end())
+                return false;
+        }
+    }
+    // Check if triangle's vertices have triangle as adjacent
+    for (std::uint32_t iT(0); iT < std::uint32_t(cdt.triangles.size()); ++iT) {
+        const triangle_t& t = cdt.triangles[iT];
+        typedef std::array<std::uint32_t, 3>::const_iterator VCit;
+        for (VCit it = t.vertices.begin(); it != t.vertices.end(); ++it) {
+            const std::vector<std::uint32_t>& tt = vertTris[*it];
+            if (std::find(tt.begin(), tt.end(), iT) == tt.end())
+                return false;
+        }
+    }
+    return true;
+}
+
+} // namespace cdt
+
+#endif // #ifndef _CONSTRAINED_DELAUNAY_TRIANGULATION_H_

src/mcut/include/mcut/internal/cdt/kdtree.h

@@ -0,0 +1,421 @@
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at https://mozilla.org/MPL/2.0/. */
+
+#ifndef KDTREE_KDTREE_H
+#define KDTREE_KDTREE_H
+
+#include "mcut/internal/cdt/utils.h"
+#include "mcut/internal/math.h"
+
+#include <cassert>
+#include <limits>
+
+namespace kdt {
+
+struct NodeSplitDirection {
+    enum Enum {
+        X,
+        Y,
+    };
+};
+
+/// Simple tree structure with alternating half splitting nodes
+/// @details Simple tree structure
+///          - Tree to incrementally add points to the structure.
+///          - Get the nearest point to a given input.
+///          - Does not check for duplicates, expect unique points.
+/// @tparam TCoordType type used for storing point coordinate.
+/// @tparam NumVerticesInLeaf The number of points per leaf.
+/// @tparam InitialStackDepth initial size of stack depth for nearest query.
+/// Should be at least 1.
+/// @tparam StackDepthIncrement increment of stack depth for nearest query when
+/// stack depth is reached.
+template <
+    typename TCoordType,
+    size_t NumVerticesInLeaf,
+    size_t InitialStackDepth,
+    size_t StackDepthIncrement>
+class kdtree_t_ {
+public:
+    typedef TCoordType coord_type;
+    typedef vec2_<coord_type> point_type;
+    typedef std::pair<point_type, std::uint32_t> value_type;
+    typedef std::vector<std::uint32_t> point_data_vec;
+    typedef point_data_vec::const_iterator pd_cit;
+    typedef std::array<std::uint32_t, 2> children_type;
+
+    /// Stores kd-tree node data
+    struct Node {
+        children_type children; ///< two children if not leaf; {0,0} if leaf
+        point_data_vec data; ///< points' data if leaf
+        /// Create empty leaf
+        Node()
+        {
+            setChildren(0, 0);
+            data.reserve(NumVerticesInLeaf);
+        }
+        /// Children setter for convenience
+        void setChildren(const std::uint32_t c1, const std::uint32_t c2)
+        {
+            children[0] = c1;
+            children[1] = c2;
+        }
+        /// Check if node is a leaf (has no valid children)
+        bool isLeaf() const
+        {
+            return children[0] == children[1];
+        }
+    };
+
+    /// Default constructor
+    kdtree_t_()
+        : m_rootDir(NodeSplitDirection::X)
+        , m_min(point_type::make(
+              -std::numeric_limits<coord_type>::max(),
+              -std::numeric_limits<coord_type>::max()))
+        , m_max(point_type::make(
+              std::numeric_limits<coord_type>::max(),
+              std::numeric_limits<coord_type>::max()))
+        , m_isRootBoxInitialized(false)
+        , m_tasksStack(InitialStackDepth, NearestTask())
+    {
+        m_root = addNewNode();
+    }
+
+    /// Constructor with bounding box known in advance
+    kdtree_t_(const point_type& min, const point_type& max)
+        : m_rootDir(NodeSplitDirection::X)
+        , m_min(min)
+        , m_max(max)
+        , m_isRootBoxInitialized(true)
+        , m_tasksStack(InitialStackDepth, NearestTask())
+    {
+        m_root = addNewNode();
+    }
+
+    /// Insert a point into kd-tree
+    /// @note external point-buffer is used to reduce kd-tree's memory footprint
+    /// @param iPoint index of point in external point-buffer
+    /// @param points external point-buffer
+    void
+    insert(const std::uint32_t& iPoint, const std::vector<point_type>& points)
+    {
+        // if point is outside root, extend tree by adding new roots
+        const point_type& pos = points[iPoint];
+        while (!isInsideBox(pos, m_min, m_max)) {
+            extendTree(pos);
+        }
+        // now insert the point into the tree
+        std::uint32_t node = m_root;
+        point_type min = m_min;
+        point_type max = m_max;
+        NodeSplitDirection::Enum dir = m_rootDir;
+
+        // below: initialized only to suppress warnings
+        NodeSplitDirection::Enum newDir(NodeSplitDirection::X);
+        coord_type mid(0);
+        point_type newMin, newMax;
+        while (true) {
+            if (m_nodes[node].isLeaf()) {
+                // add point if capacity is not reached
+                point_data_vec& pd = m_nodes[node].data;
+                if (pd.size() < NumVerticesInLeaf) {
+                    pd.push_back(iPoint);
+                    return;
+                }
+                // initialize bbox first time the root capacity is reached
+                if (!m_isRootBoxInitialized) {
+                    initializeRootBox(points);
+                    min = m_min;
+                    max = m_max;
+                }
+                // split a full leaf node
+                calcSplitInfo(min, max, dir, mid, newDir, newMin, newMax);
+                const std::uint32_t c1 = addNewNode(), c2 = addNewNode();
+                Node& n = m_nodes[node];
+                n.setChildren(c1, c2);
+                point_data_vec& c1data = m_nodes[c1].data;
+                point_data_vec& c2data = m_nodes[c2].data;
+                // move node's points to children
+                for (pd_cit it = n.data.begin(); it != n.data.end(); ++it) {
+                    whichChild(points[*it], mid, dir) == 0
+                        ? c1data.push_back(*it)
+                        : c2data.push_back(*it);
+                }
+                n.data = point_data_vec();
+            } else {
+                calcSplitInfo(min, max, dir, mid, newDir, newMin, newMax);
+            }
+            // add the point to a child
+            const std::size_t iChild = whichChild(points[iPoint], mid, dir);
+            iChild == 0 ? max = newMax : min = newMin;
+            node = m_nodes[node].children[iChild];
+            dir = newDir;
+        }
+    }
+
+    /// Query kd-tree for a nearest neighbor point
+    /// @note external point-buffer is used to reduce kd-tree's memory footprint
+    /// @param point query point position
+    /// @param points external point-buffer
+    value_type nearest(
+        const point_type& point,
+        const std::vector<point_type>& points) const
+    {
+        value_type out;
+        int iTask = -1;
+        coord_type minDistSq = std::numeric_limits<coord_type>::max();
+        m_tasksStack[++iTask] = NearestTask(m_root, m_min, m_max, m_rootDir, minDistSq);
+        while (iTask != -1) {
+            const NearestTask t = m_tasksStack[iTask--];
+            if (t.distSq > minDistSq)
+                continue;
+            const Node& n = m_nodes[t.node];
+            if (n.isLeaf()) {
+                for (pd_cit it = n.data.begin(); it != n.data.end(); ++it) {
+                    const point_type& p = points[*it];
+                    const coord_type distSq = cdt::get_square_distance(point, p);
+                    if (distSq < minDistSq) {
+                        minDistSq = distSq;
+                        out.first = p;
+                        out.second = *it;
+                    }
+                }
+            } else {
+                coord_type mid(0);
+                NodeSplitDirection::Enum newDir;
+                point_type newMin, newMax;
+                calcSplitInfo(t.min, t.max, t.dir, mid, newDir, newMin, newMax);
+
+                const coord_type distToMid = t.dir == NodeSplitDirection::X
+                    ? (point.x() - mid)
+                    : (point.y() - mid);
+                const coord_type toMidSq = distToMid * distToMid;
+
+                const std::size_t iChild = whichChild(point, mid, t.dir);
+                if (iTask + 2 >= static_cast<int>(m_tasksStack.size())) {
+                    m_tasksStack.resize(
+                        m_tasksStack.size() + StackDepthIncrement);
+                }
+                // node containing point should end up on top of the stack
+                if (iChild == 0) {
+                    m_tasksStack[++iTask] = NearestTask(
+                        n.children[1], newMin, t.max, newDir, toMidSq);
+                    m_tasksStack[++iTask] = NearestTask(
+                        n.children[0], t.min, newMax, newDir, toMidSq);
+                } else {
+                    m_tasksStack[++iTask] = NearestTask(
+                        n.children[0], t.min, newMax, newDir, toMidSq);
+                    m_tasksStack[++iTask] = NearestTask(
+                        n.children[1], newMin, t.max, newDir, toMidSq);
+                }
+            }
+        }
+        return out;
+    }
+
+private:
+    /// Add a new node and return it's index in nodes buffer
+    std::uint32_t addNewNode()
+    {
+        const std::uint32_t newNodeIndex = static_cast<std::uint32_t>(m_nodes.size());
+        m_nodes.push_back(Node());
+        return newNodeIndex;
+    }
+
+    /// Test which child point belongs to after the split
+    /// @returns 0 if first child, 1 if second child
+    std::size_t whichChild(
+        const point_type& point,
+        const coord_type& split,
+        const NodeSplitDirection::Enum dir) const
+    {
+        return static_cast<size_t>(
+            dir == NodeSplitDirection::X ? point.x() > split : point.y() > split);
+    }
+
+    /// Calculate split location, direction, and children boxes
+    static void calcSplitInfo(
+        const point_type& min,
+        const point_type& max,
+        const NodeSplitDirection::Enum dir,
+        coord_type& midOut,
+        NodeSplitDirection::Enum& newDirOut,
+        point_type& newMinOut,
+        point_type& newMaxOut)
+    {
+        newMaxOut = max;
+        newMinOut = min;
+        switch (dir) {
+        case NodeSplitDirection::X:
+            midOut = (min.x() + max.x()) / coord_type(2);
+            newDirOut = NodeSplitDirection::Y;
+            newMinOut.x() = midOut;
+            newMaxOut.x() = midOut;
+            return;
+        case NodeSplitDirection::Y:
+            midOut = (min.y() + max.y()) / coord_type(2);
+            newDirOut = NodeSplitDirection::X;
+            newMinOut.y() = midOut;
+            newMaxOut.y() = midOut;
+            return;
+        }
+    }
+
+    /// Test if point is inside a box
+    static bool isInsideBox(
+        const point_type& p,
+        const point_type& min,
+        const point_type& max)
+    {
+        return p.x() >= min.x() && p.x() <= max.x() && p.y() >= min.y() && p.y() <= max.y();
+    }
+
+    /// Extend a tree by creating new root with old root and a new node as
+    /// children
+    void extendTree(const point_type& point)
+    {
+        const std::uint32_t newRoot = addNewNode();
+        const std::uint32_t newLeaf = addNewNode();
+        switch (m_rootDir) {
+        case NodeSplitDirection::X:
+            m_rootDir = NodeSplitDirection::Y;
+            point.y() < m_min.y() ? m_nodes[newRoot].setChildren(newLeaf, m_root)
+                                  : m_nodes[newRoot].setChildren(m_root, newLeaf);
+            if (point.y() < m_min.y())
+                m_min.y() -= m_max.y() - m_min.y();
+            else if (point.y() > m_max.y())
+                m_max.y() += m_max.y() - m_min.y();
+            break;
+        case NodeSplitDirection::Y:
+            m_rootDir = NodeSplitDirection::X;
+            point.x() < m_min.x() ? m_nodes[newRoot].setChildren(newLeaf, m_root)
+                                  : m_nodes[newRoot].setChildren(m_root, newLeaf);
+            if (point.x() < m_min.x())
+                m_min.x() -= m_max.x() - m_min.x();
+            else if (point.x() > m_max.x())
+                m_max.x() += m_max.x() - m_min.x();
+            break;
+        }
+        m_root = newRoot;
+    }
+
+    /// Calculate root's box enclosing all root points
+    void initializeRootBox(const std::vector<point_type>& points)
+    {
+        const point_data_vec& data = m_nodes[m_root].data;
+        m_min = points[data.front()];
+        m_max = m_min;
+        for (pd_cit it = data.begin(); it != data.end(); ++it) {
+            const point_type& p = points[*it];
+            m_min = point_type::make(
+                std::min(m_min.x(), p.x()), std::min(m_min.y(), p.y()));
+            m_max = point_type::make(
+                std::max(m_max.x(), p.x()), std::max(m_max.y(), p.y()));
+        }
+        // Make sure bounding box does not have a zero size by adding padding:
+        // zero-size bounding box cannot be extended properly
+        const TCoordType padding(1);
+        if (m_min.x() == m_max.x()) {
+            m_min.x() -= padding;
+            m_max.x() += padding;
+        }
+        if (m_min.y() == m_max.y()) {
+            m_min.y() -= padding;
+            m_max.y() += padding;
+        }
+        m_isRootBoxInitialized = true;
+    }
+
+private:
+    std::uint32_t m_root;
+    std::vector<Node> m_nodes;
+    NodeSplitDirection::Enum m_rootDir;
+    point_type m_min;
+    point_type m_max;
+    bool m_isRootBoxInitialized;
+
+    // used for nearest query
+    struct NearestTask {
+        std::uint32_t node;
+        point_type min, max;
+        NodeSplitDirection::Enum dir;
+        coord_type distSq;
+        NearestTask()
+        {
+        }
+        NearestTask(
+            const std::uint32_t node,
+            const point_type& min,
+            const point_type& max,
+            const NodeSplitDirection::Enum dir,
+            const coord_type distSq)
+            : node(node)
+            , min(min)
+            , max(max)
+            , dir(dir)
+            , distSq(distSq)
+        {
+        }
+    };
+    // allocated in class (not in the 'nearest' method) for better performance
+    mutable std::vector<NearestTask> m_tasksStack;
+};
+
+} // namespace kdt
+
+namespace cdt {
+
+/// KD-tree holding points
+template <
+    typename TCoordType,
+    size_t NumVerticesInLeaf = 32,
+    size_t InitialStackDepth = 32,
+    size_t StackDepthIncrement = 32>
+class locator_kdtree_t {
+public:
+    /// Initialize KD-tree with points
+    void initialize(const std::vector<vec2_<TCoordType>>& points)
+    {
+        vec2_<TCoordType> min = points.front();
+        vec2_<TCoordType> max = min;
+
+        for (typename std::vector<vec2_<TCoordType>>::const_iterator it = points.begin();
+             it != points.end();
+             ++it) {
+
+            min = vec2_<TCoordType>::make(std::min(min.x(), it->x()), std::min(min.y(), it->y()));
+            max = vec2_<TCoordType>::make(std::max(max.x(), it->x()), std::max(max.y(), it->y()));
+
+        }
+
+        m_tree = kdtree_t(min, max);
+
+        for (std::uint32_t i = 0; i < (std::uint32_t)points.size(); ++i) {
+            m_tree.insert(i, points);
+        }
+    }
+    /// Add point to KD-tree
+    void add_point(const std::uint32_t i, const std::vector<vec2_<TCoordType>>& points)
+    {
+        m_tree.insert(i, points);
+    }
+
+    /// Find nearest point using R-tree
+    std::uint32_t nearPoint(
+        const vec2_<TCoordType>& pos,
+        const std::vector<vec2_<TCoordType>>& points) const
+    {
+        return m_tree.nearest(pos, points).second;
+    }
+
+private:
+    typedef kdt::kdtree_t_<TCoordType, NumVerticesInLeaf, InitialStackDepth, StackDepthIncrement> kdtree_t;
+
+    kdtree_t m_tree;
+};
+
+} // namespace cdt
+
+#endif // header guard

src/mcut/include/mcut/internal/cdt/utils.h

@@ -0,0 +1,486 @@
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at https://mozilla.org/MPL/2.0/. */
+
+#ifndef _CDT_UTILITIES_H_
+#define _CDT_UTILITIES_H_
+
+#include "mcut/internal/math.h"
+
+#include <cassert>
+#include <cmath>
+#include <limits>
+#include <vector>
+
+#include <array>
+#include <functional>
+#include <random>
+#include <tuple>
+#include <unordered_map>
+#include <unordered_set>
+
+namespace cdt {
+
+/// X- coordinate getter for vec2d_t
+template <typename T>
+const T& get_x_coord_vec2d(const vec2_<T>& v)
+{
+    return v.x();
+}
+
+/// Y-coordinate getter for vec2d_t
+template <typename T>
+const T& get_y_coord_vec2d(const vec2_<T>& v)
+{
+    return v.y();
+}
+
+/// If two 2D vectors are exactly equal
+template <typename T>
+bool operator==(const vec2_<T>& lhs, const vec2_<T>& rhs)
+{
+    return lhs.x() == rhs.x() && lhs.y() == rhs.y();
+}
+
+/// Constant representing no valid neighbor for a triangle
+const static std::uint32_t null_neighbour(std::numeric_limits<std::uint32_t>::max());
+/// Constant representing no valid vertex for a triangle
+const static std::uint32_t null_vertex(std::numeric_limits<std::uint32_t>::max());
+
+/// 2D bounding box
+template <typename T>
+struct box2d_t {
+    vec2_<T> min; ///< min box corner
+    vec2_<T> max; ///< max box corner
+
+    /// Envelop box around a point
+    void expand_with_point(const vec2_<T>& p)
+    {
+        expand_with_point(p.x(), p.y());
+    }
+    /// Envelop box around a point with given coordinates
+    void expand_with_point(const T x, const T y)
+    {
+        min.x() = std::min(x, min.x());
+        max.x() = std::max(x, max.x());
+        min.y() = std::min(y, min.y());
+        max.y() = std::max(y, max.y());
+    }
+};
+
+/// Bounding box of a collection of custom 2D points given coordinate getters
+template <
+    typename T,
+    typename TVertexIter,
+    typename TGetVertexCoordX,
+    typename TGetVertexCoordY>
+box2d_t<T> expand_with_points(
+    TVertexIter first,
+    TVertexIter last,
+    TGetVertexCoordX get_x_coord,
+    TGetVertexCoordY get_y_coord)
+{
+    const T max = std::numeric_limits<T>::max();
+    box2d_t<T> box = { { max, max }, { -max, -max } };
+
+    for (; first != last; ++first) {
+        box.expand_with_point(get_x_coord(*first), get_y_coord(*first));
+    }
+    return box;
+}
+
+/// Bounding box of a collection of 2D points
+template <typename T>
+box2d_t<T> expand_with_points(const std::vector<vec2_<T>>& vertices);
+
+/// edge_t connecting two vertices: vertex with smaller index is always first
+/// \note: hash edge_t is specialized at the bottom
+struct edge_t {
+    
+    edge_t(std::uint32_t iV1, std::uint32_t iV2)
+        : m_vertices(
+            iV1 < iV2 ? std::make_pair(iV1, iV2) : std::make_pair(iV2, iV1))
+    {
+    }
+
+    inline bool operator==(const edge_t& other) const
+    {
+        return m_vertices == other.m_vertices;
+    }
+
+    inline bool operator!=(const edge_t& other) const
+    {
+        return !(this->operator==(other));
+    }
+
+    inline std::uint32_t v1() const
+    {
+        return m_vertices.first;
+    }
+
+    inline std::uint32_t v2() const
+    {
+        return m_vertices.second;
+    }
+
+    inline const std::pair<std::uint32_t, std::uint32_t>& verts() const
+    {
+        return m_vertices;
+    }
+
+private:
+    std::pair<std::uint32_t, std::uint32_t> m_vertices;
+};
+
+/// Get edge first vertex
+inline std::uint32_t edge_get_v1(const edge_t& e)
+{
+    return e.v1();
+}
+
+/// Get edge second vertex
+inline std::uint32_t edge_get_v2(const edge_t& e)
+{
+    return e.v2();
+}
+
+/// Get edge second vertex
+inline edge_t edge_make(std::uint32_t iV1, std::uint32_t iV2)
+{
+    return edge_t(iV1, iV2);
+}
+
+/// triangulator_t triangle (CCW winding)
+/* Counter-clockwise winding:
+       v3
+       /\
+    n3/  \n2
+     /____\
+   v1  n1  v2                 */
+struct triangle_t {
+
+    std::array<std::uint32_t, 3> vertices; 
+    std::array<std::uint32_t, 3> neighbors; 
+
+    /**
+     * Factory method
+     * @note needed for c++03 compatibility (no uniform initialization
+     * available)
+     */
+    static triangle_t
+    make(const std::array<std::uint32_t, 3>& vertices, const std::array<std::uint32_t, 3>& neighbors)
+    {
+        triangle_t t = { vertices, neighbors };
+        return t;
+    }
+};
+
+/// Location of point on a triangle
+struct point_to_triangle_location_t {
+    /// Enum
+    enum Enum {
+        INSIDE,
+        OUTSIDE,
+        ON_1ST_EDGE,
+        ON_2ND_EDGE,
+        ON_3RD_EDGE,
+    };
+};
+
+/// Relative location of point to a line
+struct point_to_line_location_t {
+    /// Enum
+    enum Enum {
+        LEFT_SIDE,
+        RIGHT_SIDE,
+        COLLINEAR,
+    };
+};
+
+} // namespace cdt
+
+#ifndef CDT_USE_AS_COMPILED_LIBRARY
+
+#include <stdexcept>
+
+namespace cdt {
+
+//*****************************************************************************
+// box2d_t
+//*****************************************************************************
+template <typename T>
+box2d_t<T> expand_with_points(const std::vector<vec2_<T>>& vertices)
+{
+    return expand_with_points<T>(
+        vertices.begin(), vertices.end(), get_x_coord_vec2d<T>, get_y_coord_vec2d<T>);
+}
+
+//*****************************************************************************
+// Utility functions
+//*****************************************************************************
+
+/// Advance vertex or neighbor index counter-clockwise
+inline std::uint32_t ccw(std::uint32_t i)
+{
+    return std::uint32_t((i + 1) % 3);
+}
+
+/// Advance vertex or neighbor index clockwise
+inline std::uint32_t cw(std::uint32_t i)
+{
+    return std::uint32_t((i + 2) % 3);
+}
+
+/// Check if location is classified as on any of three edges
+inline bool check_on_edge(const point_to_triangle_location_t::Enum location)
+{
+    return location > point_to_triangle_location_t::OUTSIDE;
+}
+
+/// Neighbor index from a on-edge location
+/// \note Call only if located on the edge!
+inline std::uint32_t edge_neighbour(const point_to_triangle_location_t::Enum location)
+{
+    assert(location >= point_to_triangle_location_t::ON_1ST_EDGE);
+    return static_cast<std::uint32_t>(location - point_to_triangle_location_t::ON_1ST_EDGE);
+}
+
+#if 0
+/// Orient p against line v1-v2 2D: robust geometric predicate
+template <typename T>
+T orient2D(const vec2_<T>& p, const vec2_<T>& v1, const vec2_<T>& v2)
+{
+    return orient2d(v1.x(), v1.y(), v2.x(), v2.y(), p.x(), p.y());
+}
+#endif
+
+/// Classify value of orient2d predicate
+template <typename T>
+point_to_line_location_t::Enum
+classify_orientation(const T orientation, const T orientationTolerance = T(0))
+{
+    if (orientation < -orientationTolerance)
+        return point_to_line_location_t::RIGHT_SIDE;
+    if (orientation > orientationTolerance)
+        return point_to_line_location_t::LEFT_SIDE;
+    return point_to_line_location_t::COLLINEAR;
+}
+
+/// Check if point lies to the left of, to the right of, or on a line
+template <typename T>
+point_to_line_location_t::Enum locate_point_wrt_line(
+    const vec2_<T>& p,
+    const vec2_<T>& v1,
+    const vec2_<T>& v2,
+    const T orientationTolerance = T(0))
+{
+    return classify_orientation(orient2d(p, v1, v2), orientationTolerance);
+}
+
+/// Check if point a lies inside of, outside of, or on an edge of a triangle
+template <typename T>
+point_to_triangle_location_t::Enum locate_point_wrt_triangle(
+    const vec2_<T>& p,
+    const vec2_<T>& v1,
+    const vec2_<T>& v2,
+    const vec2_<T>& v3)
+{
+    point_to_triangle_location_t::Enum result = point_to_triangle_location_t::INSIDE;
+    point_to_line_location_t::Enum edgeCheck = locate_point_wrt_line(p, v1, v2);
+    if (edgeCheck == point_to_line_location_t::RIGHT_SIDE)
+        return point_to_triangle_location_t::OUTSIDE;
+    if (edgeCheck == point_to_line_location_t::COLLINEAR)
+        result = point_to_triangle_location_t::ON_1ST_EDGE;
+    edgeCheck = locate_point_wrt_line(p, v2, v3);
+    if (edgeCheck == point_to_line_location_t::RIGHT_SIDE)
+        return point_to_triangle_location_t::OUTSIDE;
+    if (edgeCheck == point_to_line_location_t::COLLINEAR)
+        result = point_to_triangle_location_t::ON_2ND_EDGE;
+    edgeCheck = locate_point_wrt_line(p, v3, v1);
+    if (edgeCheck == point_to_line_location_t::RIGHT_SIDE)
+        return point_to_triangle_location_t::OUTSIDE;
+    if (edgeCheck == point_to_line_location_t::COLLINEAR)
+        result = point_to_triangle_location_t::ON_3RD_EDGE;
+    return result;
+}
+
+/// Opposed neighbor index from vertex index
+inline std::uint32_t get_opposite_neighbour_from_vertex(const std::uint32_t vertIndex)
+{
+    MCUT_ASSERT(vertIndex < 3);
+
+    if (vertIndex == std::uint32_t(0))
+        return std::uint32_t(1);
+    if (vertIndex == std::uint32_t(1))
+        return std::uint32_t(2);
+    if (vertIndex == std::uint32_t(2))
+        return std::uint32_t(0);
+    throw std::runtime_error("Invalid vertex index");
+}
+/// Opposed vertex index from neighbor index
+inline std::uint32_t opposite_vertex_from_neighbour(const std::uint32_t neighborIndex)
+{
+    if (neighborIndex == std::uint32_t(0))
+        return std::uint32_t(2);
+    if (neighborIndex == std::uint32_t(1))
+        return std::uint32_t(0);
+    if (neighborIndex == std::uint32_t(2))
+        return std::uint32_t(1);
+    throw std::runtime_error("Invalid neighbor index");
+}
+
+/// Index of triangle's neighbor opposed to a vertex
+inline std::uint32_t
+opposite_triangle_index(const triangle_t& tri, const std::uint32_t iVert)
+{
+    for (std::uint32_t vi = std::uint32_t(0); vi < std::uint32_t(3); ++vi)
+        if (iVert == tri.vertices[vi])
+            return get_opposite_neighbour_from_vertex(vi);
+    throw std::runtime_error("Could not find opposed triangle index");
+}
+
+/// Index of triangle's neighbor opposed to an edge
+inline std::uint32_t opposite_triangle_index(
+    const triangle_t& tri,
+    const std::uint32_t iVedge1,
+    const std::uint32_t iVedge2)
+{
+    for (std::uint32_t vi = std::uint32_t(0); vi < std::uint32_t(3); ++vi) {
+        const std::uint32_t iVert = tri.vertices[vi];
+        if (iVert != iVedge1 && iVert != iVedge2)
+            return get_opposite_neighbour_from_vertex(vi);
+    }
+    throw std::runtime_error("Could not find opposed-to-edge triangle index");
+}
+
+/// Index of triangle's vertex opposed to a triangle
+inline std::uint32_t
+get_opposite_vertex_index(const triangle_t& tri, const std::uint32_t iTopo)
+{
+    for (std::uint32_t ni = std::uint32_t(0); ni < std::uint32_t(3); ++ni)
+        if (iTopo == tri.neighbors[ni])
+            return opposite_vertex_from_neighbour(ni);
+    throw std::runtime_error("Could not find opposed vertex index");
+}
+
+/// If triangle has a given neighbor return neighbor-index, throw otherwise
+inline std::uint32_t
+get_neighbour_index(const triangle_t& tri, std::uint32_t iTnbr)
+{
+    for (std::uint32_t ni = std::uint32_t(0); ni < std::uint32_t(3); ++ni)
+        if (iTnbr == tri.neighbors[ni])
+            return ni;
+    throw std::runtime_error("Could not find neighbor triangle index");
+}
+
+/// If triangle has a given vertex return vertex-index, throw otherwise
+inline std::uint32_t get_vertex_index(const triangle_t& tri, const std::uint32_t iV)
+{
+    for (std::uint32_t i = std::uint32_t(0); i < std::uint32_t(3); ++i)
+        if (iV == tri.vertices[i])
+            return i;
+    throw std::runtime_error("Could not find vertex index in triangle");
+}
+
+/// Given triangle and a vertex find opposed triangle
+inline std::uint32_t
+get_opposite_triangle_index(const triangle_t& tri, const std::uint32_t iVert)
+{
+    return tri.neighbors[opposite_triangle_index(tri, iVert)];
+}
+
+/// Given two triangles, return vertex of first triangle opposed to the second
+inline std::uint32_t
+get_opposed_vertex_index(const triangle_t& tri, std::uint32_t iTopo)
+{
+    return tri.vertices[get_opposite_vertex_index(tri, iTopo)];
+}
+
+/// Test if point lies in a circumscribed circle of a triangle
+template <typename T>
+bool check_is_in_circumcircle(
+    const vec2_<T>& p,
+    const vec2_<T>& v1,
+    const vec2_<T>& v2,
+    const vec2_<T>& v3)
+{
+    const double p_[2] = { static_cast<double>(p.x()), static_cast<double>(p.y()) };
+    const double v1_[2] = { static_cast<double>(v1.x()), static_cast<double>(v1.y()) };
+    const double v2_[2] = { static_cast<double>(v2.x()), static_cast<double>(v2.y()) };
+    const double v3_[2] = { static_cast<double>(v3.x()), static_cast<double>(v3.y()) };
+
+    return ::incircle(v1_, v2_, v3_, p_) > T(0);
+}
+
+/// Test if two vertices share at least one common triangle
+inline bool check_vertices_share_edge(const std::vector<std::uint32_t>& aTris, const std::vector<std::uint32_t>& bTris)
+{
+    for (std::vector<std::uint32_t>::const_iterator it = aTris.begin(); it != aTris.end(); ++it)
+        if (std::find(bTris.begin(), bTris.end(), *it) != bTris.end())
+            return true;
+    return false;
+}
+
+template <typename T>
+T get_square_distance(const T ax, const T ay, const T bx, const T by)
+{
+    const T dx = bx - ax;
+    const T dy = by - ay;
+    return dx * dx + dy * dy;
+}
+
+template <typename T>
+T distance(const T ax, const T ay, const T bx, const T by)
+{
+    return std::sqrt(get_square_distance(ax, ay, bx, by));
+}
+
+template <typename T>
+T distance(const vec2_<T>& a, const vec2_<T>& b)
+{
+    return distance(a.x(), a.y(), b.x(), b.y());
+}
+
+template <typename T>
+T get_square_distance(const vec2_<T>& a, const vec2_<T>& b)
+{
+    return get_square_distance(a.x(), a.y(), b.x(), b.y());
+}
+
+} // namespace cdt
+
+#endif
+
+//*****************************************************************************
+// Specialize hash functions
+//*****************************************************************************
+namespace std {
+/// edge_t hasher
+template <>
+struct hash<cdt::edge_t> {
+    /// Hash operator
+    std::size_t operator()(const cdt::edge_t& e) const
+    {
+        return get_hashed_edge_index(e);
+    }
+
+private:
+    static void combine_hash_values(std::size_t& seed, const std::uint32_t& key)
+    {
+        seed ^= std::hash<std::uint32_t>()(key) + 0x9e3779b9 + (seed << 6) + (seed >> 2);
+    }
+    static std::size_t get_hashed_edge_index(const cdt::edge_t& e)
+    {
+        const std::pair<std::uint32_t, std::uint32_t>& vv = e.verts();
+        std::size_t seed1(0);
+        combine_hash_values(seed1, vv.first);
+        combine_hash_values(seed1, vv.second);
+        std::size_t seed2(0);
+        combine_hash_values(seed2, vv.second);
+        combine_hash_values(seed2, vv.first);
+        return std::min(seed1, seed2);
+    }
+};
+} // namespace std/boost
+
+#endif // header guard

src/mcut/include/mcut/internal/frontend.h

@@ -0,0 +1,846 @@
+/**
+ * Copyright (c) 2021-2022 Floyd M. Chitalu.
+ * All rights reserved.
+ *
+ * NOTE: This file is licensed under GPL-3.0-or-later (default).
+ * A commercial license can be purchased from Floyd M. Chitalu.
+ *
+ * License details:
+ *
+ * (A)  GNU General Public License ("GPL"); a copy of which you should have
+ *      recieved with this file.
+ * 	    - see also: <http://www.gnu.org/licenses/>
+ * (B)  Commercial license.
+ *      - email: floyd.m.chitalu@gmail.com
+ *
+ * The commercial license options is for users that wish to use MCUT in
+ * their products for comercial purposes but do not wish to release their
+ * software products under the GPL license.
+ *
+ * Author(s)     : Floyd M. Chitalu
+ */
+
+/**
+ * @file mcut.h
+ * @author Floyd M. Chitalu
+ * @date 11 July 2022
+ *
+ * @brief API-function implementations.
+ *
+ * NOTE: This header file defines the pre- and post-cutting processing of mesh
+ * data, which includes any intermediate correctons/modifications to the user's
+ * input meshes like 'polygon partitioning'.
+ *
+ */
+
+#ifndef _FRONTEND_H_
+#define _FRONTEND_H_
+
+#include "mcut/mcut.h"
+
+#include <future>
+#include <map>
+#include <memory>
+#include <string>
+
+#include "mcut/internal/tpool.h"
+
+#include "mcut/internal/kernel.h"
+
+/*
+std::invalid_argument: related to the input parameters
+std::runtime_error: system runtime error e.g. out of memory
+std::logic_error: a bug caught through an assertion failure
+std::exception: unknown error source e.g. probably another bug
+*/
+#define CATCH_POSSIBLE_EXCEPTIONS(logstr)              \
+    catch (std::invalid_argument & e0)                 \
+    {                                                  \
+        logstr = e0.what();                            \
+        return_value = McResult::MC_INVALID_VALUE;     \
+    }                                                  \
+    catch (std::runtime_error & e1)                    \
+    {                                                  \
+        logstr = e1.what();                            \
+        return_value = McResult::MC_INVALID_OPERATION; \
+    }                                                  \
+    catch (std::logic_error & e2)                      \
+    {                                                  \
+        logstr = e2.what();                            \
+        return_value = McResult::MC_RESULT_MAX_ENUM;   \
+    }                                                  \
+    catch (std::exception & e3)                        \
+    {                                                  \
+        logstr = e3.what();                            \
+        return_value = McResult::MC_RESULT_MAX_ENUM;   \
+    }
+
+extern thread_local std::string per_thread_api_log_str; // frontend.cpp
+
+extern "C" void create_context_impl(
+    McContext* pContext, McFlags flags, uint32_t num_helper_threads) noexcept(false);
+
+extern "C" void debug_message_callback_impl(
+    McContext context,
+    pfn_mcDebugOutput_CALLBACK cb,
+    const McVoid* userParam) noexcept(false);
+
+extern "C" void get_debug_message_log_impl(McContext context,
+    McUint32 count, McSize bufSize,
+    McDebugSource* sources, McDebugType* types, McDebugSeverity* severities,
+    McSize* lengths, McChar* messageLog, McUint32& numFetched);
+
+extern "C" void debug_message_control_impl(
+    McContext context,
+    McDebugSource source,
+    McDebugType type,
+    McDebugSeverity severity,
+    bool enabled) noexcept(false);
+
+extern "C" void get_info_impl(
+    const McContext context,
+    McFlags info,
+    McSize bytes,
+    McVoid* pMem,
+    McSize* pNumBytes) noexcept(false);
+
+extern "C" void bind_state_impl(
+    const McContext context,
+    McFlags stateInfo,
+    McSize bytes,
+    const McVoid* pMem);
+
+extern "C" void create_user_event_impl(McEvent* event, McContext context);
+
+extern "C" void set_user_event_status_impl(McEvent event, McInt32 execution_status);
+
+extern "C" void get_event_info_impl(
+    const McEvent event,
+    McFlags info,
+    McSize bytes,
+    McVoid* pMem,
+    McSize* pNumBytes) noexcept(false);
+
+extern "C" void set_event_callback_impl(
+    McEvent eventHandle,
+    pfn_McEvent_CALLBACK eventCallback,
+    McVoid* data);
+
+extern "C" void wait_for_events_impl(
+    uint32_t numEventsInWaitlist,
+    const McEvent* pEventWaitList,
+    McResult& runtimeStatusFromAllPrecedingEvents) noexcept(false);
+
+extern "C" void dispatch_impl(
+    McContext context,
+    McFlags flags,
+    const McVoid* pSrcMeshVertices,
+    const uint32_t* pSrcMeshFaceIndices,
+    const uint32_t* pSrcMeshFaceSizes,
+    uint32_t numSrcMeshVertices,
+    uint32_t numSrcMeshFaces,
+    const McVoid* pCutMeshVertices,
+    const uint32_t* pCutMeshFaceIndices,
+    const uint32_t* pCutMeshFaceSizes,
+    uint32_t numCutMeshVertices,
+    uint32_t numCutMeshFaces,
+    uint32_t numEventsInWaitlist,
+    const McEvent* pEventWaitList,
+    McEvent* pEvent) noexcept(false);
+
+extern "C" void dispatch_planar_section_impl(
+    McContext context,
+    McFlags flags,
+    const McVoid* pSrcMeshVertices,
+    const uint32_t* pSrcMeshFaceIndices,
+    const uint32_t* pSrcMeshFaceSizes,
+    uint32_t numSrcMeshVertices,
+    uint32_t numSrcMeshFaces,
+    const McDouble* pNormalVector,
+    const McDouble sectionOffset,
+    uint32_t numEventsInWaitlist,
+    const McEvent* pEventWaitList,
+    McEvent* pEvent) noexcept(false);
+
+extern "C" void get_connected_components_impl(
+    const McContext context,
+    const McConnectedComponentType connectedComponentType,
+    const uint32_t numEntries,
+    McConnectedComponent* pConnComps,
+    uint32_t* numConnComps,
+    uint32_t numEventsInWaitlist,
+    const McEvent* pEventWaitList,
+    McEvent* pEvent) noexcept(false);
+
+extern "C" void get_connected_component_data_impl(
+    const McContext context,
+    const McConnectedComponent connCompId,
+    McFlags flags,
+    McSize bytes,
+    McVoid* pMem,
+    McSize* pNumBytes,
+    uint32_t numEventsInWaitlist,
+    const McEvent* pEventWaitList,
+    McEvent* pEvent) noexcept(false);
+
+extern "C" void release_connected_components_impl(
+    const McContext context,
+    uint32_t numConnComps,
+    const McConnectedComponent* pConnComps) noexcept(false);
+
+extern "C" void release_context_impl(
+    McContext context) noexcept(false);
+
+extern "C" void release_events_impl(uint32_t numEvents, const McEvent* pEvents);
+
+// base struct from which other structs represent connected components inherit
+struct connected_component_t {
+    virtual ~connected_component_t() {};
+    McConnectedComponentType type = (McConnectedComponentType)0;
+    McConnectedComponent m_user_handle = MC_NULL_HANDLE;
+    // array_mesh_t indexArrayMesh;
+    // hmesh_t mesh;
+    std::shared_ptr<output_mesh_info_t> kernel_hmesh_data;
+
+    //
+    std::shared_ptr< //
+        std::unordered_map< //
+            fd_t /*child face*/,
+            fd_t /*parent face in the [user-provided] source mesh*/
+            > //
+        >
+        source_hmesh_child_to_usermesh_birth_face; // fpPartitionChildFaceToCorrespondingInputSrcMeshFace
+    std::shared_ptr< //
+        std::unordered_map< //
+            fd_t /*child face*/,
+            fd_t /*parent face in the [user-provided] cut mesh*/
+            >>
+        cut_hmesh_child_to_usermesh_birth_face; // fpPartitionChildFaceToCorrespondingInputCutMeshFace
+    // descriptors and coordinates of new vertices that are added into an input mesh (source mesh or cut mesh)
+    // in order to carry out partitioning
+    std::shared_ptr<std::unordered_map<vd_t, vec3>> source_hmesh_new_poly_partition_vertices; // addedFpPartitioningVerticesOnCorrespondingInputSrcMesh
+    std::shared_ptr<std::unordered_map<vd_t, vec3>> cut_hmesh_new_poly_partition_vertices; // addedFpPartitioningVerticesOnCorrespondingInputCutMesh
+    uint32_t internal_sourcemesh_vertex_count; // init from source_hmesh.number_of_vertices()
+    uint32_t client_sourcemesh_vertex_count; // init from numSrcMeshVertices
+    uint32_t internal_sourcemesh_face_count; // init from source_hmesh.number_of_faces()
+    uint32_t client_sourcemesh_face_count; // init from source_hmesh_face_count OR numSrcMeshFaces
+    // Stores the contiguous array of unsigned integers that define
+    // a triangulation of all [non-triangle faces] of the connected component.
+    // This vector is only populated if client invokes mcGetConnectedComponnentData
+    // with flag MC_CONNECTED_COMPONENT_DATA_FACE_TRIANGULATION and has the effect of
+    // triangulating every non-triangle face in the connected component.
+    std::vector<uint32_t> cdt_index_cache;
+    bool cdt_index_cache_initialized = false;
+    // stores the mapping between a CDT triangle in the connected component and
+    // the original "birth-face" in an input mesh (source mesh or cut mesh)
+    std::vector<uint32_t> cdt_face_map_cache;
+    bool cdt_face_map_cache_initialized = false;
+#if defined(MCUT_WITH_COMPUTE_HELPER_THREADPOOL)
+    // Stores the number of vertices per face of CC. This is an optimization
+    // because there is a possibility that face-sizes may (at-minimum) be queried
+    // twice by user. The first case is during the populating (i.e. second) call to the API
+    // mcGetConnectedComponentData(..., MC_CONNECTED_COMPONENT_DATA_FACE_SIZE, ...);
+    // The second case is during the populating (i.e. second) call to the API
+    // mcGetConnectedComponentData(..., MC_CONNECTED_COMPONENT_DATA_FACE, ...);.
+    // The key detail here is that the second case requires knowledge of the
+    // number of vertices in each face in order to know how to schedule parallel
+    // work with prefix-sums etc.. Thus, the optimization is useful only if
+    // building MCUT with multi-threading
+    std::vector<uint32_t> face_sizes_cache;
+    bool face_sizes_cache_initialized = false;
+    // see documentation of face_sizes_cache above
+    // Similar concepts but applied to MC_CONNECTED_COMPONENT_DATA_FACE_ADJACENT_FACE
+    std::vector<uint32_t> face_adjacent_faces_size_cache;
+    bool face_adjacent_faces_size_cache_initialized = false;
+#endif // #if defined(MCUT_WITH_COMPUTE_HELPER_THREADPOOL)
+    // non-zero if origin source and cut-mesh where perturbed
+    vec3 perturbation_vector = vec3(0.0);
+};
+
+// struct representing a fragment
+struct fragment_cc_t : public connected_component_t {
+    McFragmentLocation fragmentLocation = (McFragmentLocation)0;
+    McFragmentSealType srcMeshSealType = (McFragmentSealType)0;
+    McPatchLocation patchLocation = (McPatchLocation)0;
+};
+
+// struct representing a patch
+struct patch_cc_t : public connected_component_t {
+    McPatchLocation patchLocation = (McPatchLocation)0;
+};
+
+// struct representing a seam
+struct seam_cc_t : public connected_component_t {
+    McSeamOrigin origin = (McSeamOrigin)0;
+};
+
+// struct representing an input (user provided mesh)
+struct input_cc_t : public connected_component_t {
+    McInputOrigin origin = (McInputOrigin)0;
+};
+
+struct event_t {
+    std::future<void> m_future; // used to wait on event
+    // used to synchronise access to variables associated with the callback
+    // function.
+    // This also also allows us to overcome the edgecase that mcSetEventCallback
+    // is called after the task associated with an event has been completed,
+    // in which case the new callback will be invoked immediately.
+    // see "set_callback_data()" below
+    std::mutex m_callback_mutex;
+    struct {
+        // optional user callback, which is invoked when associated task is finished
+        pfn_McEvent_CALLBACK m_fn_ptr;
+        // pointer passed to user provided callback function
+        McVoid* m_data_ptr;
+        // atomic boolean flag indicating whether the callback associated with event
+        // object has been called
+        std::atomic<bool> m_invoked;
+    } m_callback_info;
+    // atomic boolean flag indicating whether the task associated with event
+    // object has completed running
+    std::atomic<bool> m_finished;
+    McEvent m_user_handle; // handle used by client app to reference this event object
+    // the Manager thread which was assigned the task of managing the task associated with this event object.
+    std::atomic<uint32_t> m_responsible_thread_id;
+    std::atomic<int32_t> m_runtime_exec_status; // API return code associated with respective task (for user to query)
+    std::atomic<size_t> m_timestamp_submit;
+    std::atomic<size_t> m_timestamp_start;
+    std::atomic<size_t> m_timestamp_end;
+    std::atomic<uint32_t> m_command_exec_status;
+    bool m_profiling_enabled;
+    McCommandType m_command_type;
+    // A callable object that also holds an std::future. Its purpose is to emulate
+    // the internal representation of an API task, where this time the task is actually
+    // a user command since this pointer is define ONLY for user events.
+    // The std::future object of the packaged task is used to initialize m_future
+    // when this event is a user event. This our internal mechanism allowing for
+    // API command to be able to effectively wait on user events.
+    std::unique_ptr<std::packaged_task<void()>> m_user_API_command_task_emulator;
+    McContext m_context;
+
+    const char* get_cmd_type_str()
+    {
+        switch (m_command_type) {
+        case McCommandType::MC_COMMAND_DISPATCH: {
+            return "MC_COMMAND_DISPATCH";
+        } break;
+        case McCommandType::MC_COMMAND_GET_CONNECTED_COMPONENT_DATA: {
+            return "MC_COMMAND_GET_CONNECTED_COMPONENT_DATA";
+        } break;
+        case McCommandType::MC_COMMAND_GET_CONNECTED_COMPONENTS: {
+            return "MC_COMMAND_GET_CONNECTED_COMPONENTS";
+        } break;
+        case McCommandType::MC_COMMAND_USER: {
+            return "MC_COMMAND_USER";
+        } break;
+        case McCommandType::MC_COMMAND_UKNOWN: {
+            return "MC_COMMAND_UKNOWN";
+        } break;
+        default:
+            fprintf(stderr, "unknown command type value (%d)\n", (int)m_command_type);
+            return "UNKNOWN VALUE";
+        }
+    }
+    explicit event_t(McEvent user_handle, McCommandType command_type)
+        : m_user_handle(user_handle)
+        , m_responsible_thread_id(UINT32_MAX)
+        , m_runtime_exec_status(MC_NO_ERROR)
+        , m_timestamp_submit(0)
+        , m_timestamp_start(0)
+        , m_timestamp_end(0)
+        , m_command_exec_status(MC_RESULT_MAX_ENUM)
+        , m_profiling_enabled(true)
+        , m_command_type(command_type)
+        , m_user_API_command_task_emulator(nullptr)
+        , m_context(nullptr)
+    {
+        log_msg("[MCUT] Create event (type=" << get_cmd_type_str() <<", handle=" << m_user_handle << ")");
+
+        m_callback_info.m_fn_ptr = nullptr;
+        m_callback_info.m_data_ptr = nullptr;
+        m_finished.store(false);
+        m_callback_info.m_invoked.store(true); // so that we do not call a null pointer/needless invoke the callback in the destructor
+    }
+
+    ~event_t()
+    {
+
+        if (m_callback_info.m_invoked.load() == false && m_callback_info.m_fn_ptr != nullptr && m_runtime_exec_status.load() == MC_NO_ERROR) {
+            MCUT_ASSERT(m_user_handle != MC_NULL_HANDLE);
+            (*(m_callback_info.m_fn_ptr))(m_user_handle, m_callback_info.m_data_ptr);
+        }
+
+        log_msg("[MCUT] Destroy event (type=" << get_cmd_type_str() << ", handle=" << m_user_handle << ")");
+    }
+
+    inline std::size_t get_time_since_epoch()
+    {
+        return std::chrono::duration_cast<std::chrono::nanoseconds>(std::chrono::system_clock::now().time_since_epoch()).count();
+    }
+
+    inline void log_submit_time()
+    {
+        if (m_profiling_enabled) {
+            this->m_timestamp_submit.store(get_time_since_epoch());
+        }
+        // TODO: use specific acquire-release semantics
+        // see e.g.: https://stackoverflow.com/questions/13632344/understanding-c11-memory-fences
+        m_command_exec_status.store(McEventCommandExecStatus::MC_SUBMITTED);
+    }
+
+    inline void log_start_time()
+    {
+        if (m_profiling_enabled) {
+            this->m_timestamp_start.store(get_time_since_epoch());
+        }
+        m_command_exec_status = McEventCommandExecStatus::MC_RUNNING;
+    }
+
+    // logs time and sets m_command_exec_status to MC_COMPLETE
+    inline void log_end_time()
+    {
+        if (m_profiling_enabled) {
+            this->m_timestamp_end.store(get_time_since_epoch());
+        }
+        m_command_exec_status.store(McEventCommandExecStatus::MC_COMPLETE);
+    }
+
+    // thread-safe function to set the callback function for an event object
+    void set_callback_data(McEvent handle, pfn_McEvent_CALLBACK fn_ptr, McVoid* data_ptr)
+    {
+        std::lock_guard<std::mutex> lock(m_callback_mutex); // exclusive access
+
+        m_user_handle = handle;
+        m_callback_info.m_fn_ptr = fn_ptr;
+        m_callback_info.m_data_ptr = data_ptr;
+        m_callback_info.m_invoked.store(false);
+
+        if (m_finished.load() == true) { // see mutex documentation
+            // immediately invoke the callback
+            (*(m_callback_info.m_fn_ptr))(m_user_handle, m_callback_info.m_data_ptr);
+            m_callback_info.m_invoked.store(true);
+        }
+    }
+
+    // update the status of the event object to "finished"
+    void notify_task_complete(McResult exec_status)
+    {
+        m_finished = true;
+        m_runtime_exec_status = exec_status;
+
+        std::lock_guard<std::mutex> lock(m_callback_mutex);
+        if (m_callback_info.m_invoked.load() == false && m_callback_info.m_fn_ptr != nullptr) {
+            MCUT_ASSERT(m_user_handle != MC_NULL_HANDLE);
+            (*(m_callback_info.m_fn_ptr))(m_user_handle, m_callback_info.m_data_ptr);
+            m_callback_info.m_invoked.store(true);
+        }
+    }
+};
+
+// init in frontened.cpp
+extern threadsafe_list<std::shared_ptr<event_t>> g_events;
+extern std::atomic<std::uintptr_t> g_objects_counter; // a counter that is used to assign a unique value to a McObject handle that will be returned to the user
+extern std::once_flag g_objects_counter_init_flag;
+
+// our custome deleter function for std::unique_ptr variable of an array type
+template <typename Derived>
+void fn_delete_cc(connected_component_t* p)
+{
+    log_msg("[MCUT] Destroy connected component " << p->m_user_handle);
+    delete dynamic_cast<Derived*>(p);
+}
+
+// struct defining the state of a context object
+struct context_t {
+private:
+    std::atomic<bool> m_done;
+    std::vector<thread_safe_queue<function_wrapper>> m_queues;
+    // Master/Manager thread(s) which are responsible for running the API calls
+    // When a user of MCUT calls one of the APIs (e.g. mcEnqueueDispatch) the task
+    // of actually executing everything related to that task will be handled by
+    // one Manager thread. This manager thread itself will be involved in
+    // computing some/all part of the respective task (think of it as the "main"
+    // thread insofar as the API task is concerned). Some API tasks contain code
+    // sections that run in parallel, which is where the Manager thread will also
+    // submit tasks to the shared compute threadpool ("m_compute_threadpool").
+    // NOTE: must be declared after "thread_pool_terminate" and "work_queues"
+    std::vector<std::thread> m_api_threads;
+    // join_threads m_joiner;
+
+#if defined(MCUT_WITH_COMPUTE_HELPER_THREADPOOL)
+    // A pool of threads that is shared by manager threads to execute e.g. parallel
+    // section of MCUT API tasks (see e.g. frontend.cpp and kernel.cpp)
+    std::unique_ptr<thread_pool> m_compute_threadpool;
+#endif
+
+    // The state and flag variable current used to configure the next dispatch call
+    McFlags m_flags = (McFlags)0;
+
+    std::atomic<McDouble> m_general_position_enforcement_constant;
+    std::atomic<McUint32> m_max_num_perturbation_attempts;
+    std::atomic<McConnectedComponentFaceWindingOrder> m_connected_component_winding_order;
+
+    void api_thread_main(uint32_t thread_id)
+    {
+        log_msg("[MCUT] Launch API thread " << std::this_thread::get_id() << " (" << thread_id << ")");
+
+        do {
+            function_wrapper task;
+
+            // We try_pop() first in case the task "producer" (API) thread
+            // already invoked cond_var.notify_one() of "m_queues[thread_id]""
+            // BEFORE current thread first-entered this function.
+            if (!m_queues[thread_id].try_pop(task)) {
+                m_queues[thread_id].wait_and_pop(task);
+            }
+
+            if (m_done) {
+                break;
+            }
+
+            task();
+
+        } while (true);
+
+        log_msg("[MCUT] Shutdown API thread " << std::this_thread::get_id() << " (" << thread_id << ")");
+    }
+
+public:
+    context_t(McContext handle, McFlags flags
+#if defined(MCUT_WITH_COMPUTE_HELPER_THREADPOOL)
+        ,
+        uint32_t num_compute_threads
+#endif
+        )
+        : m_done(false)
+        // , m_joiner(m_api_threads)
+        , m_flags(flags)
+        , m_general_position_enforcement_constant(1e-4)
+        , m_max_num_perturbation_attempts(1 << 2),
+        m_connected_component_winding_order(McConnectedComponentFaceWindingOrder::MC_CONNECTED_COMPONENT_FACE_WINDING_ORDER_AS_GIVEN)
+        , m_user_handle(handle)
+        , dbgCallbackBitfieldSource(0)
+        , dbgCallbackBitfieldType(0)
+        , dbgCallbackBitfieldSeverity(0)
+    {
+        log_msg("\n[MCUT] Create context " << m_user_handle);
+
+        try {
+            const uint32_t manager_thread_count = (flags & MC_OUT_OF_ORDER_EXEC_MODE_ENABLE) ? 2 : 1;
+
+            m_queues = std::vector<thread_safe_queue<function_wrapper>>(manager_thread_count);
+
+            for (uint32_t i = 0; i < manager_thread_count; ++i) {
+                m_queues[i].set_done_ptr(&m_done);
+                m_api_threads.push_back(std::thread(&context_t::api_thread_main, this, i));
+            }
+#if defined(MCUT_WITH_COMPUTE_HELPER_THREADPOOL)
+            // create the pool of compute threads. These are the worker threads that
+            // can be tasked with work from any manager-thread. Thus, manager threads
+            // share the available/user-specified compute threads.
+            m_compute_threadpool = std::unique_ptr<thread_pool>(new thread_pool(num_compute_threads, manager_thread_count));
+#endif
+        } catch (...) {
+            shutdown();
+
+            log_msg("[MCUT] Destroy context due to exception" << m_user_handle);
+            throw;
+        }
+    }
+
+    ~context_t()
+    {
+        shutdown();
+        log_msg("[MCUT] Destroy context " << m_user_handle);
+    }
+
+    void shutdown()
+    {
+        m_done = true;
+        
+        std::atomic_thread_fence(std::memory_order_acq_rel);
+
+#if defined(MCUT_WITH_COMPUTE_HELPER_THREADPOOL)
+        m_compute_threadpool.reset();
+#endif
+        for (int i = (int)m_api_threads.size() - 1; i >= 0; --i) {
+            m_queues[i].disrupt_wait_for_data();
+            if (m_api_threads[i].joinable()) {
+                m_api_threads[i].join();
+            }
+        }
+    }
+
+    McContext m_user_handle;
+
+    // returns the flags which determine the runtime configuration of this context
+    const McFlags& get_flags() const
+    {
+        return this->m_flags;
+    }
+
+    // returns (user controllable) epsilon representing the maximum by which the cut-mesh
+    // can be perturbed on any axis
+    McDouble get_general_position_enforcement_constant() const
+    {
+        return this->m_general_position_enforcement_constant.load(std::memory_order_acquire);
+    }
+
+    void set_general_position_enforcement_constant(McDouble new_value)
+    {
+        this->m_general_position_enforcement_constant.store(new_value, std::memory_order_release);
+    }
+
+    // returns (user controllable) maximum number of times by which the cut-mesh
+    // can be perturbed before giving (input likely need to be preprocessed)
+    McUint32 get_general_position_enforcement_attempts() const
+    {
+        return this->m_max_num_perturbation_attempts.load(std::memory_order_acquire);
+    }
+
+    void set_general_position_enforcement_attempts(McUint32 new_value)
+    {
+        this->m_max_num_perturbation_attempts.store(new_value, std::memory_order_release);
+    }
+
+ McConnectedComponentFaceWindingOrder get_connected_component_winding_order() const
+    {
+        return this->m_connected_component_winding_order.load(std::memory_order_acquire);
+    }
+
+    void set_connected_component_winding_order(McConnectedComponentFaceWindingOrder new_value)
+    {
+        this->m_connected_component_winding_order.store(new_value, std::memory_order_release);
+    }
+    
+
+#if defined(MCUT_WITH_COMPUTE_HELPER_THREADPOOL)
+    thread_pool& get_shared_compute_threadpool()
+    {
+        return m_compute_threadpool.get()[0];
+    }
+#endif
+
+    template <typename FunctionType>
+    McEvent prepare_and_submit_API_task(McCommandType cmdType, uint32_t numEventsInWaitlist, const McEvent* pEventWaitList, FunctionType api_fn)
+    {
+        //
+        // create the event object associated with the enqueued task
+        //
+
+        std::shared_ptr<event_t> event_ptr = std::shared_ptr<event_t>(new event_t(
+            reinterpret_cast<McEvent>(g_objects_counter.fetch_add(1, std::memory_order_relaxed)),
+            cmdType));
+
+        MCUT_ASSERT(event_ptr != nullptr);
+
+        g_events.push_front(event_ptr);
+
+        //event_ptr->m_user_handle = reinterpret_cast<McEvent>(g_objects_counter.fetch_add(1, std::memory_order_relaxed));
+        event_ptr->m_profiling_enabled = (this->m_flags & MC_PROFILING_ENABLE) != 0;
+        // event_ptr->m_command_type = cmdType;
+
+        event_ptr->log_submit_time();
+
+        // List of events the enqueued task depends on
+        //
+        // local copy that will be captured by-value (user permitted to re-use pEventWaitList)
+        const std::vector<McEvent> event_waitlist(pEventWaitList, pEventWaitList + numEventsInWaitlist);
+
+        //
+        // Determine which manager thread to assign the task
+        //
+
+        // the id of manager thread that will be assigned the current task
+        uint32_t responsible_thread_id = UINT32_MAX;
+
+        for (std::vector<McEvent>::const_iterator waitlist_iter = event_waitlist.cbegin(); waitlist_iter != event_waitlist.cend(); ++waitlist_iter) {
+            const McEvent& parent_task_event_handle = *waitlist_iter;
+
+            const std::shared_ptr<event_t> parent_task_event_ptr = g_events.find_first_if([=](std::shared_ptr<event_t> e) { return e->m_user_handle == parent_task_event_handle; });
+
+            if (parent_task_event_ptr == nullptr) {
+                throw std::invalid_argument("invalid event in waitlist");
+            }
+
+            const bool parent_task_is_not_finished = parent_task_event_ptr->m_finished.load() == false;
+
+            if (parent_task_is_not_finished && parent_task_event_ptr->m_command_type != McCommandType::MC_COMMAND_USER) {
+                // id of manager thread, which was assigned the parent task
+                responsible_thread_id = parent_task_event_ptr->m_responsible_thread_id.load();
+
+                MCUT_ASSERT(responsible_thread_id != UINT32_MAX);
+                MCUT_ASSERT(responsible_thread_id < (uint32_t)m_api_threads.size());
+
+                break;
+            }
+        }
+
+        const bool have_responsible_thread = responsible_thread_id != UINT32_MAX;
+
+        if (!have_responsible_thread) {
+            uint32_t thread_with_empty_queue = UINT32_MAX;
+
+            for (uint32_t i = 0; i < (uint32_t)m_api_threads.size(); ++i) {
+                if (m_queues[(i + 1) % (uint32_t)m_api_threads.size()].empty() == true) {
+                    thread_with_empty_queue = i;
+                    break;
+                }
+            }
+
+            if (thread_with_empty_queue != UINT32_MAX) {
+                responsible_thread_id = thread_with_empty_queue;
+            } else { // all threads have work to do
+                responsible_thread_id = 0; // just pick thread 0
+            }
+        }
+
+        //
+        // Package-up the task as a synchronised operation that will wait for
+        // other tasks in the event_waitlist, compute the operation, and finally update
+        // the respective event state with the completion status.
+        //
+
+        std::weak_ptr<event_t> event_weak_ptr(event_ptr);
+
+        std::packaged_task<void()> task(
+            [=]() {
+                McResult runtime_status_from_all_preceding_events = McResult::MC_NO_ERROR;
+
+                if (!event_waitlist.empty()) {
+                    wait_for_events_impl((uint32_t)event_waitlist.size(), &event_waitlist[0], runtime_status_from_all_preceding_events); // block until events are done
+                }
+
+                // if any previous event failed then we cannot proceed with this task.
+                // i.e. no-Op
+                if (runtime_status_from_all_preceding_events != McResult::MC_NO_ERROR) {
+                    return;
+                }
+
+                MCUT_ASSERT(!event_weak_ptr.expired());
+
+                {
+                    std::shared_ptr<event_t> event = event_weak_ptr.lock();
+
+                    MCUT_ASSERT(event != nullptr);
+
+                    {
+                        McResult return_value = McResult::MC_NO_ERROR;
+                        per_thread_api_log_str.clear();
+
+                        event->log_start_time();
+
+                        try {
+                            api_fn(); // execute the API function.
+                        }
+                        CATCH_POSSIBLE_EXCEPTIONS(per_thread_api_log_str); // exceptions may be thrown due to runtime errors, which must be reported back to user
+
+                        if (!per_thread_api_log_str.empty()) {
+
+                            std::fprintf(stderr, "%s(...) -> %s (EventID=%p)\n", __FUNCTION__, per_thread_api_log_str.c_str(), event == nullptr ? (McEvent)0 : event->m_user_handle);
+
+                            if (return_value == McResult::MC_NO_ERROR) // i.e. problem with basic local parameter checks
+                            {
+                                return_value = McResult::MC_INVALID_VALUE;
+                            }
+                        }
+
+                        event->notify_task_complete(return_value); // updated event state to indicate task completion (lock-based)
+                        event->log_end_time();
+                    }
+                }
+            });
+
+        event_ptr->m_future = task.get_future(); // the future we can later wait on via mcWaitForEVents
+        event_ptr->m_responsible_thread_id = responsible_thread_id;
+
+        m_queues[responsible_thread_id].push(std::move(task)); // enqueue task to be executed when responsible API thread is free
+
+        return event_ptr->m_user_handle;
+    }
+
+    // the current set of connected components associated with context
+    threadsafe_list<std::shared_ptr<connected_component_t>> connected_components;
+
+    // McFlags dispatchFlags = (McFlags)0;
+
+    // client/user debugging variables
+    // ------------------------------
+
+    // function pointer to user-define callback function for status/erro reporting
+    pfn_mcDebugOutput_CALLBACK debugCallback = nullptr;
+    // user provided data for callback
+    const McVoid* debugCallbackUserParam = nullptr;
+
+    std::mutex debugCallbackMutex;
+    // controller for permmited messages based on the source of message
+    std::atomic<McFlags> dbgCallbackBitfieldSource;
+    // controller for permmited messages based on the type of message
+    std::atomic<McFlags> dbgCallbackBitfieldType;
+    // controller for permmited messages based on the severity of message
+    std::atomic<McFlags> dbgCallbackBitfieldSeverity;
+    bool dbgCallbackAllowAsyncCalls = true;
+
+    void set_debug_callback_data(pfn_mcDebugOutput_CALLBACK cb, const McVoid* data_ptr)
+    {
+        std::lock_guard<std::mutex> lguard(debugCallbackMutex);
+        debugCallback = cb;
+        debugCallbackUserParam = data_ptr;
+    }
+
+    struct debug_log_msg_t {
+        McDebugSource source;
+        McDebugType type;
+        McDebugSeverity severity;
+        std::string str;
+    };
+
+    std::vector<debug_log_msg_t> m_debug_logs;
+
+    // function to invoke the user-provided debug call back
+    void dbg_cb(McDebugSource source,
+        McDebugType type,
+        unsigned int id, // unused
+        McDebugSeverity severity,
+        const std::string& message)
+    {
+        if (this->m_flags & McContextCreationFlags::MC_DEBUG) // information logged only during debug mode
+        {
+            std::unique_lock<std::mutex> ulock(debugCallbackMutex, std::defer_lock);
+
+            if (!dbgCallbackAllowAsyncCalls) {
+                ulock.lock();
+            } // otherwise the callback will be invoked asynchronously
+
+            // can we log this type of message? (based on user preferences via mcDebugMessageControl)
+            const bool canLog = ((uint32_t)source & dbgCallbackBitfieldSource.load(std::memory_order_acquire)) && //
+                ((uint32_t)type & dbgCallbackBitfieldType.load(std::memory_order_acquire)) && //
+                ((uint32_t)severity & dbgCallbackBitfieldSeverity.load(std::memory_order_acquire));
+
+            if (canLog) {
+
+                if (debugCallback != nullptr) { // user gave us a callback function pointer
+
+                    (*debugCallback)(source, type, id, severity, message.length(), message.c_str(), debugCallbackUserParam);
+
+                } else // write to the internal log
+                {
+                    m_debug_logs.emplace_back(debug_log_msg_t());
+
+                    debug_log_msg_t& dbg_log = m_debug_logs.back();
+
+                    dbg_log.source = source;
+                    dbg_log.type = type;
+                    dbg_log.severity = severity;
+                    dbg_log.str = message;
+                }
+            }
+        }
+    }
+};
+
+// list of contexts created by client/user
+extern "C" threadsafe_list<std::shared_ptr<context_t>> g_contexts;
+
+#endif // #ifndef _FRONTEND_H_

src/mcut/include/mcut/internal/hmesh.h

@@ -0,0 +1,640 @@
+/**
+ * Copyright (c) 2021-2022 Floyd M. Chitalu.
+ * All rights reserved.
+ *
+ * NOTE: This file is licensed under GPL-3.0-or-later (default).
+ * A commercial license can be purchased from Floyd M. Chitalu.
+ *
+ * License details:
+ *
+ * (A)  GNU General Public License ("GPL"); a copy of which you should have
+ *      recieved with this file.
+ * 	    - see also: <http://www.gnu.org/licenses/>
+ * (B)  Commercial license.
+ *      - email: floyd.m.chitalu@gmail.com
+ *
+ * The commercial license options is for users that wish to use MCUT in
+ * their products for comercial purposes but do not wish to release their
+ * software products under the GPL license.
+ *
+ * Author(s)     : Floyd M. Chitalu
+ */
+
+#ifndef MCUT_HALFEDGE_MESH_H_
+#define MCUT_HALFEDGE_MESH_H_
+
+#include "mcut/internal/math.h"
+#include "mcut/internal/utils.h"
+
+#include <algorithm>
+#include <limits>
+#include <map>
+#include <memory>
+#include <vector>
+#include <cstdint>
+
+template <typename T>
+class descriptor_t_ {
+public:
+    typedef unsigned int index_type;
+    descriptor_t_() { }
+    virtual ~descriptor_t_() { }
+    explicit descriptor_t_(index_type i = (std::numeric_limits<index_type>::max)())
+        : m_value(i)
+    {
+    }
+
+    operator index_type() const { return m_value; }
+
+    void reset() { m_value = (std::numeric_limits<index_type>::max)(); }
+
+    bool is_valid() const
+    {
+        index_type inf = (std::numeric_limits<index_type>::max)();
+        return m_value != inf;
+    }
+
+    descriptor_t_& operator=(const index_type& _rhs)
+    {
+        m_value = _rhs;
+        return *this;
+    }
+
+    descriptor_t_& operator=(const T& _rhs) const
+    {
+        m_value = _rhs.m_value;
+        return *this;
+    }
+
+    bool operator==(const T& _rhs) const
+    {
+        return m_value == _rhs.m_value;
+    }
+
+    bool operator!=(const T& _rhs) const
+    {
+        return m_value != _rhs.m_value;
+    }
+
+    bool operator<(const T& _rhs) const
+    {
+        return m_value < _rhs.m_value;
+    }
+
+    descriptor_t_& operator++()
+    {
+        ++m_value;
+        return *this;
+    }
+
+    descriptor_t_& operator--()
+    {
+        --m_value;
+        return *this;
+    }
+
+    descriptor_t_ operator++(int)
+    {
+        descriptor_t_ tmp(*this);
+        ++m_value;
+        return tmp;
+    }
+
+    descriptor_t_ operator--(int)
+    {
+        descriptor_t_ tmp(*this);
+        --m_value;
+        return tmp;
+    }
+
+    descriptor_t_& operator+=(std::ptrdiff_t n)
+    {
+        m_value = (unsigned int)(m_value + n);
+        return *this;
+    }
+
+protected:
+    unsigned int m_value;
+};
+
+class halfedge_descriptor_t : public descriptor_t_<halfedge_descriptor_t> {
+public:
+    halfedge_descriptor_t()
+        : descriptor_t_<halfedge_descriptor_t>(std::numeric_limits<index_type>::max())
+    {
+    }
+
+    explicit halfedge_descriptor_t(descriptor_t_<halfedge_descriptor_t>::index_type idx)
+        : descriptor_t_<halfedge_descriptor_t>(idx)
+    {
+    }
+
+    virtual ~halfedge_descriptor_t()
+    {
+    }
+};
+
+class edge_descriptor_t : public descriptor_t_<edge_descriptor_t> {
+public:
+    edge_descriptor_t()
+        : descriptor_t_<edge_descriptor_t>((std::numeric_limits<index_type>::max)())
+    {
+    }
+
+    explicit edge_descriptor_t(descriptor_t_<edge_descriptor_t>::index_type idx)
+        : descriptor_t_<edge_descriptor_t>(idx)
+    {
+    }
+
+    virtual ~edge_descriptor_t()
+    {
+    }
+};
+
+class face_descriptor_t : public descriptor_t_<face_descriptor_t> {
+public:
+    face_descriptor_t()
+        : descriptor_t_<face_descriptor_t>((std::numeric_limits<index_type>::max)())
+    {
+    }
+
+    explicit face_descriptor_t(descriptor_t_<face_descriptor_t>::index_type idx)
+        : descriptor_t_<face_descriptor_t>(idx)
+    {
+    }
+
+    virtual ~face_descriptor_t()
+    {
+    }
+};
+
+class vertex_descriptor_t : public descriptor_t_<vertex_descriptor_t> {
+public:
+    vertex_descriptor_t()
+        : descriptor_t_<vertex_descriptor_t>((std::numeric_limits<index_type>::max)())
+    {
+    }
+
+    explicit vertex_descriptor_t(descriptor_t_<vertex_descriptor_t>::index_type idx)
+        : descriptor_t_<vertex_descriptor_t>(idx)
+    {
+    }
+
+    virtual ~vertex_descriptor_t()
+    {
+    }
+};
+
+template <typename T>
+struct id_ {
+    typedef T type;
+};
+
+template <typename V>
+class array_iterator_t;
+
+struct halfedge_data_t : id_<halfedge_descriptor_t> {
+    vertex_descriptor_t t; // target vertex
+    face_descriptor_t f; // face
+    halfedge_descriptor_t o; // opposite halfedge
+    halfedge_descriptor_t n; // next halfedge
+    halfedge_descriptor_t p; // previous halfedge
+    edge_descriptor_t e; // edge
+    
+
+    halfedge_data_t()
+    //: o(null_halfedge()), n(null_halfedge()), p(null_halfedge()), t(null_vertex()), e(null_edge()), f(null_face())
+    {
+    }
+};
+
+struct edge_data_t : id_<edge_descriptor_t> {
+    halfedge_descriptor_t h; // primary halfedge (even idx)
+};
+
+struct face_data_t : id_<face_descriptor_t> {
+    std::vector<halfedge_descriptor_t> m_halfedges;
+};
+
+struct vertex_data_t : id_<vertex_descriptor_t> {
+    vec3 p; // geometry coordinates
+    //std::vector<face_descriptor_t> m_faces; // ... incident to vertex // TODO: this is not needed (can be inferred from "m_halfedges")
+    std::vector<halfedge_descriptor_t> m_halfedges; // ... which point to vertex (note: can be used to infer edges too)
+};
+
+typedef std::vector<vertex_data_t> vertex_array_t;
+typedef std::vector<edge_data_t> edge_array_t;
+typedef std::vector<halfedge_data_t> halfedge_array_t;
+typedef std::vector<face_data_t> face_array_t;
+
+typedef array_iterator_t<face_array_t> face_array_iterator_t;
+typedef array_iterator_t<vertex_array_t> vertex_array_iterator_t;
+typedef array_iterator_t<edge_array_t> edge_array_iterator_t;
+typedef array_iterator_t<halfedge_array_t> halfedge_array_iterator_t;
+
+/*
+    Internal mesh data structure used for cutting meshes
+
+    Memory Management
+
+    Memory management is semi-automatic. Memory grows as more elements are added to the structure but does not shrink when elements are removed.
+    When you add elements and the capacity of the underlying vector is exhausted, the vector reallocates memory.
+    As descriptors are basically indices, they refer to the same element after a reallocation.
+    When you remove an element it is only marked as removed.
+    Internally it is put in a free list, and when you add elements to the surface mesh, they are taken from the free list in case it is not empty.
+
+    For all elements there is a function to obtain the number of used elements, as well as the number of used [and] removed elements.
+    For vertices the functions are hmesh_t::number_of_vertices() and hmesh_t::number_of_internal_vertices(), respectively.
+    The first function is slightly different from the free function num_vertices(const G&) of the BGL package.
+
+    Iterators such as hmesh_t::vertex_iterator_t only enumerate elements that are not marked as deleted.
+*/
+class hmesh_t {
+public:
+    hmesh_t();
+    ~hmesh_t();
+
+    // static member functions
+    // -----------------------
+
+    static vertex_descriptor_t null_vertex();
+    static halfedge_descriptor_t null_halfedge();
+    static edge_descriptor_t null_edge();
+    static face_descriptor_t null_face();
+
+    // regular member functions
+    // ------------------------
+
+    // excluding removed elements
+    int number_of_vertices() const;
+    int number_of_edges() const;
+    int number_of_halfedges() const;
+    int number_of_faces() const;
+
+    vertex_descriptor_t source(const halfedge_descriptor_t& h) const;
+    vertex_descriptor_t target(const halfedge_descriptor_t& h) const;
+    halfedge_descriptor_t opposite(const halfedge_descriptor_t& h) const;
+    halfedge_descriptor_t prev(const halfedge_descriptor_t& h) const;
+    halfedge_descriptor_t next(const halfedge_descriptor_t& h) const;
+
+    void set_next(const halfedge_descriptor_t& h, const halfedge_descriptor_t& nxt);
+    void set_previous(const halfedge_descriptor_t& h, const halfedge_descriptor_t& prev);
+
+    edge_descriptor_t edge(const halfedge_descriptor_t& h) const;
+    face_descriptor_t face(const halfedge_descriptor_t& h) const;
+
+    vertex_descriptor_t vertex(const edge_descriptor_t e, const int v) const;
+
+    bool is_border(const halfedge_descriptor_t h);
+    bool is_border(const edge_descriptor_t e);
+
+    halfedge_descriptor_t halfedge(const edge_descriptor_t e, const int i) const;
+    // finds a halfedge between two vertices. Returns a default constructed halfedge descriptor, if source and target are not connected.
+    halfedge_descriptor_t halfedge(const vertex_descriptor_t s, const vertex_descriptor_t t, bool strict_check = false) const;
+    // finds an edge between two vertices. Returns a default constructed halfedge descriptor, if source and target are not connected.
+    edge_descriptor_t edge(const vertex_descriptor_t s, const vertex_descriptor_t t, bool strict_check = false) const;
+
+    vertex_descriptor_t add_vertex(const vec3& point);
+
+    vertex_descriptor_t add_vertex(const double& x, const double& y, const double& z);
+    // adds an edges into the mesh data structure, creating incident halfedges, and returns the
+    // halfedge whole target is "v1"
+    halfedge_descriptor_t add_edge(const vertex_descriptor_t v0, const vertex_descriptor_t v1);
+    face_descriptor_t add_face(const std::vector<vertex_descriptor_t>& vi);
+    // checks whether adding this face will violate 2-manifoldness (i.e. halfedge 
+    // construction rules) which would lead to creating a non-manifold edge 
+    // (one that is referenced by more than 2 faces which is illegal). 
+    bool is_insertable(const std::vector<vertex_descriptor_t> &vi) const;
+
+    // also disassociates (not remove) any halfedges(s) and vertices incident to face
+    void remove_face(const face_descriptor_t f);
+    // also disassociates (not remove) the halfedges(s) and vertex incident to this halfedge
+    void remove_halfedge(halfedge_descriptor_t h);
+    // also disassociates (not remove) any face(s) incident to edge via its halfedges, and also disassociates the halfedges
+    void remove_edge(const edge_descriptor_t e, bool remove_halfedges = true);
+    void remove_vertex(const vertex_descriptor_t v);
+    void remove_elements();
+
+    void reset();
+
+    int number_of_internal_faces() const;
+    int number_of_internal_edges() const;
+    int number_of_internal_halfedges() const;
+    int number_of_internal_vertices() const;
+
+    int number_of_vertices_removed() const;
+    int number_of_edges_removed() const;
+    int number_of_halfedges_removed() const;
+    int number_of_faces_removed() const;
+
+    bool is_removed(face_descriptor_t f) const;
+    bool is_removed(edge_descriptor_t e) const;
+    bool is_removed(halfedge_descriptor_t h) const;
+    bool is_removed(vertex_descriptor_t v) const;
+
+    void reserve_for_additional_vertices(std::uint32_t n);
+    void reserve_for_additional_edges(std::uint32_t n);
+    void reserve_for_additional_halfedges(std::uint32_t n);
+    void reserve_for_additional_faces(std::uint32_t n);
+    void reserve_for_additional_elements(std::uint32_t additional_vertices);
+
+    ///
+
+    template <typename I = int>
+    I get_removed_elements(id_<I>)
+    {
+        return I(); // unused
+    }
+
+    const std::vector<vertex_descriptor_t>& get_removed_elements(id_<array_iterator_t<vertex_array_t>>) const;
+    const std::vector<edge_descriptor_t>& get_removed_elements(id_<array_iterator_t<edge_array_t>>) const;
+    const std::vector<halfedge_descriptor_t>& get_removed_elements(id_<array_iterator_t<halfedge_array_t>>) const;
+    const std::vector<face_descriptor_t>& get_removed_elements(id_<array_iterator_t<face_array_t>>) const;
+
+    //
+    template <typename I = int>
+    I elements_begin_(id_<I>)
+    {
+        return I(); // unused
+    }
+
+    const vertex_array_iterator_t elements_begin_(id_<vertex_array_iterator_t>, bool account_for_removed_elems = true) const;
+    const edge_array_iterator_t elements_begin_(id_<edge_array_iterator_t>, bool account_for_removed_elems = true) const;
+    const halfedge_array_iterator_t elements_begin_(id_<halfedge_array_iterator_t>, bool account_for_removed_elems = true) const;
+    const face_array_iterator_t elements_begin_(id_<face_array_iterator_t>, bool account_for_removed_elems = true) const;
+
+    // returns the number of removed mesh elements (vertices, edges, faces or halfedges) between [start, end)
+    template <typename I>
+    uint32_t count_removed_elements_in_range(const array_iterator_t<I>& start, const array_iterator_t<I>& end) const
+    {
+        const long long N = (uint32_t)(end - start); // length including removed elements
+        MCUT_ASSERT(N >= 0);
+        if (N == 0) {
+            return 0;
+        }
+
+        // raw starting ptr offset
+        const uint32_t start_ = (std::uint32_t)(start - elements_begin_(id_<array_iterator_t<I>> {}, false));
+        uint32_t n = 0;
+
+        for (auto elem_descr : get_removed_elements(id_<array_iterator_t<I>> {})) {
+            const uint32_t descr = (uint32_t)elem_descr;
+
+            if (descr >= start_ && (descr <= (start_ + (uint32_t)(N - 1)))) {
+                ++n;
+            }
+        }
+        return n;
+    }
+
+    const vec3& vertex(const vertex_descriptor_t& vd) const;
+    // returns vector of halfedges which point to vertex (i.e. "v" is their target)
+    const std::vector<halfedge_descriptor_t>& get_halfedges_around_vertex(const vertex_descriptor_t v) const;
+    std::vector<vertex_descriptor_t> get_vertices_around_face(const face_descriptor_t f, uint32_t prepend_offset = 0) const;
+    void get_vertices_around_face(std::vector<vertex_descriptor_t>& vertex_descriptors, const face_descriptor_t f, uint32_t prepend_offset=0) const;
+    std::vector<vertex_descriptor_t> get_vertices_around_vertex(const vertex_descriptor_t v) const;
+    void get_vertices_around_vertex(std::vector<vertex_descriptor_t>& vertices_around_vertex, const vertex_descriptor_t v) const;
+    uint32_t get_num_vertices_around_face(const face_descriptor_t f) const;
+    const std::vector<halfedge_descriptor_t>& get_halfedges_around_face(const face_descriptor_t f) const;
+    const std::vector<face_descriptor_t> get_faces_around_face(const face_descriptor_t f, const std::vector<halfedge_descriptor_t>* halfedges_around_face_ = nullptr) const;
+    void get_faces_around_face( std::vector<face_descriptor_t>& faces_around_face, const face_descriptor_t f, const std::vector<halfedge_descriptor_t>* halfedges_around_face_ = nullptr) const;
+    uint32_t get_num_faces_around_face(const face_descriptor_t f, const std::vector<halfedge_descriptor_t>* halfedges_around_face_ = nullptr) const;
+    
+    // iterators
+    // ---------
+
+    vertex_array_iterator_t vertices_begin(bool account_for_removed_elems = true) const;
+    vertex_array_iterator_t vertices_end() const;
+    edge_array_iterator_t edges_begin(bool account_for_removed_elems = true) const;
+    edge_array_iterator_t edges_end() const;
+    halfedge_array_iterator_t halfedges_begin(bool account_for_removed_elems = true) const;
+    halfedge_array_iterator_t halfedges_end() const;
+    face_array_iterator_t faces_begin(bool account_for_removed_elems = true) const;
+    face_array_iterator_t faces_end() const;
+
+    const std::vector<vertex_descriptor_t>& get_removed_vertices() const;
+    const std::vector<edge_descriptor_t>& get_removed_edges() const;
+    const std::vector<halfedge_descriptor_t>& get_removed_halfedges() const;
+    const std::vector<face_descriptor_t>& get_removed_faces() const;
+
+private:
+    // member variables
+    // ----------------
+
+    std::vector<vertex_data_t> m_vertices;
+    std::vector<edge_data_t> m_edges;
+    std::vector<halfedge_data_t> m_halfedges;
+    std::vector<face_data_t> m_faces;
+
+    // NOTE: I use std::vector because we'll have very few (typically zero)
+    // elements removed at a given time. In fact removal only happens during
+    // input-mesh face-partitioning to resolve floating polygons, which is
+    // rare. Maybe in the future things change...
+    std::vector<face_descriptor_t> m_faces_removed;
+    std::vector<edge_descriptor_t> m_edges_removed;
+    std::vector<halfedge_descriptor_t> m_halfedges_removed;
+    std::vector<vertex_descriptor_t> m_vertices_removed;
+
+}; // class hmesh_t {
+
+typedef vertex_descriptor_t vd_t;
+typedef halfedge_descriptor_t hd_t;
+typedef edge_descriptor_t ed_t;
+typedef face_descriptor_t fd_t;
+
+void write_off(const char* fpath, const hmesh_t& mesh);
+void read_off(hmesh_t& mesh, const char* fpath);
+
+template <typename V = face_array_t>
+class array_iterator_t : public V::const_iterator {
+    const hmesh_t* mesh_ptr;
+    typedef typename V::const_iterator std_iterator_base_class;
+    typedef typename V::value_type::type element_descriptor_type;
+    typename V::value_type* operator->() = delete;
+
+public:
+    array_iterator_t()
+        : V::const_iterator()
+        , mesh_ptr(nullptr) {};
+    array_iterator_t(typename V::const_iterator it_, const hmesh_t* const mesh)
+        : V::const_iterator(it_)
+        , mesh_ptr(mesh)
+    {
+    }
+
+    const hmesh_t* get_mesh_ptr() const
+    {
+        return mesh_ptr;
+    }
+
+    typename V::value_type::type operator*()
+    {
+        size_t raw_index = (*this) - cbegin<>(false);
+        element_descriptor_type d((std::uint32_t)raw_index);
+        return d;
+    }
+
+    // prefix increment (++i)
+    // increment pointer to the next valid element (i.e. we skip removed elements).
+    array_iterator_t<V>& operator++()
+    {
+        bool cur_elem_is_removed = false;
+        bool reached_end = false;
+        do {
+            V::const_iterator::operator++();
+            reached_end = (*this) == cend<>();
+            cur_elem_is_removed = false;
+
+            if (!reached_end) {
+                const std::size_t diff = ((*this) - cbegin<array_iterator_t<V>>(false));
+                element_descriptor_type raw_descriptor((std::uint32_t)diff); // std::distance(cbegin<array_iterator_t<V>>(false), (*this)); // O(1) ??
+                cur_elem_is_removed = mesh_ptr->is_removed(raw_descriptor);
+                if (!cur_elem_is_removed) {
+                    break;
+                }
+            }
+
+            // keep iterating until the value pointed to after the (++i) operator is a valid element
+            // i.e. one that is not marked removed!
+
+        } while (cur_elem_is_removed && !reached_end);
+
+        return (*this);
+    }
+
+    // we provide this overide to ensure that stl functions like std::advance, work properly
+    // by accounting for removed elements
+    array_iterator_t<V>& operator+=(std::ptrdiff_t n)
+    {
+        V::const_iterator::operator+=(n); // raw ptr shift (i.e. ignoring that there may be removed elements)
+
+        bool cur_elem_is_removed = false;
+        bool reached_end = (*this) == cend<>();
+        cur_elem_is_removed = mesh_ptr->is_removed(*(*this));
+        while (!reached_end && cur_elem_is_removed) {
+            V::const_iterator::operator++(); //++(*this);
+            size_t raw_descriptor = *(*this); // (*this) - cbegin<array_iterator_t<V>>(false); //std::distance(cbegin<array_iterator_t<V>>(false), (*this)); // O(1) ??
+            cur_elem_is_removed = mesh_ptr->is_removed(element_descriptor_type((std::uint32_t)raw_descriptor));
+            if (!cur_elem_is_removed) {
+                break;
+            }
+
+            reached_end = (*this) == cend<>();
+        }
+        return *this;
+    }
+
+    // The following are helper functions which are specialised (via type-deduction)
+    // for the type of mesh elements that *this* iterator walks over in "mesh_ptr"
+    // e.g. faces. These functions are used to determine when *this* iterator has
+    // reached the end of the respective std::map data structure over which we are
+    // iterating.
+
+    template <typename I = array_iterator_t<V>>
+    I cend()
+    {
+        return cend(id_<I>()); // https://stackoverflow.com/questions/3052579/explicit-specialization-in-non-namespace-scope
+    }
+
+    template <typename I = array_iterator_t<V>>
+    I cbegin(bool account_for_removed_elems)
+    {
+        return cbegin(account_for_removed_elems, id_<I>());
+    }
+
+private:
+    // postfix increment (i++)
+    // NOTE: This overide is private to simplify implementation, and we don't need it
+    array_iterator_t<V> operator++(int)
+    {
+        MCUT_ASSERT(false);
+        return cend<>();
+    }
+
+    template <typename I = array_iterator_t<V>>
+    I cend(id_<I>)
+    {
+        return I(); // unused stub
+    }
+
+    template <typename I = array_iterator_t<V>>
+    I cbegin(bool account_for_removed_elems, id_<I>)
+    {
+        return I(account_for_removed_elems); // unused stub
+    }
+
+    vertex_array_iterator_t cbegin(bool account_for_removed_elems, id_<vertex_array_iterator_t> = {});
+    vertex_array_iterator_t cend(id_<vertex_array_iterator_t>);
+
+    edge_array_iterator_t cbegin(bool account_for_removed_elems, id_<edge_array_iterator_t> = {});
+    edge_array_iterator_t cend(id_<edge_array_iterator_t>);
+
+    halfedge_array_iterator_t cbegin(bool account_for_removed_elems, id_<halfedge_array_iterator_t> = {});
+    halfedge_array_iterator_t cend(id_<halfedge_array_iterator_t>);
+
+    face_array_iterator_t cbegin(bool account_for_removed_elems, id_<face_array_iterator_t> = {});
+    face_array_iterator_t cend(id_<face_array_iterator_t>);
+}; // class array_iterator_t : public V::const_iterator
+
+namespace std {
+#if 1
+template <>
+inline typename edge_array_iterator_t::difference_type distance(
+    edge_array_iterator_t first,
+    edge_array_iterator_t last)
+{
+    MCUT_ASSERT(first.get_mesh_ptr() == last.get_mesh_ptr());
+    edge_array_iterator_t it = first;
+    edge_array_iterator_t::difference_type dist = last - first;
+
+    uint32_t r = it.get_mesh_ptr()->count_removed_elements_in_range(first, last);
+    if (r > 0) {
+        dist = dist - r;
+    }
+
+    MCUT_ASSERT(dist >= 0);
+
+    return dist;
+}
+#endif
+#if 0
+    template <>
+    void advance(
+        hmesh_t::array_iterator_t<hmesh_t::edge_array_t> &iter,
+        typename std::iterator_traits<hmesh_t::array_iterator_t<hmesh_t::edge_array_t>>::difference_type n);
+#endif
+
+template <>
+struct hash<vertex_descriptor_t> {
+    std::size_t operator()(const vertex_descriptor_t& k) const
+    {
+        return std::hash<typename vertex_descriptor_t::index_type>()(static_cast<typename vertex_descriptor_t::index_type>(k));
+    }
+};
+
+template <>
+struct hash<edge_descriptor_t> {
+    std::size_t operator()(const edge_descriptor_t& k) const
+    {
+        return std::hash<typename edge_descriptor_t::index_type>()(static_cast<typename edge_descriptor_t::index_type>(k));
+    }
+};
+
+template <>
+struct hash<halfedge_descriptor_t> {
+    std::size_t operator()(const halfedge_descriptor_t& k) const
+    {
+        return std::hash<typename halfedge_descriptor_t::index_type>()(static_cast<typename halfedge_descriptor_t::index_type>(k));
+    }
+};
+
+template <>
+struct hash<face_descriptor_t> {
+    std::size_t operator()(const face_descriptor_t& k) const
+    {
+        return std::hash<typename face_descriptor_t::index_type>()(static_cast<typename face_descriptor_t::index_type>(k));
+    }
+};
+}
+
+#endif // #ifndef MCUT_HALFEDGE_MESH_H_

src/mcut/include/mcut/internal/kernel.h

@@ -0,0 +1,233 @@
+/**
+ * Copyright (c) 2021-2022 Floyd M. Chitalu.
+ * All rights reserved.
+ *
+ * NOTE: This file is licensed under GPL-3.0-or-later (default).
+ * A commercial license can be purchased from Floyd M. Chitalu.
+ *
+ * License details:
+ *
+ * (A)  GNU General Public License ("GPL"); a copy of which you should have
+ *      recieved with this file.
+ * 	    - see also: <http://www.gnu.org/licenses/>
+ * (B)  Commercial license.
+ *      - email: floyd.m.chitalu@gmail.com
+ *
+ * The commercial license options is for users that wish to use MCUT in
+ * their products for comercial purposes but do not wish to release their
+ * software products under the GPL license.
+ *
+ * Author(s)     : Floyd M. Chitalu
+ */
+
+#ifndef MCUT_KERNEL_H
+#define MCUT_KERNEL_H
+#include <mcut/internal/bvh.h>
+#include <mcut/internal/hmesh.h>
+#if defined(MCUT_WITH_COMPUTE_HELPER_THREADPOOL)
+#include <mcut/internal/tpool.h>
+#endif
+
+#include <map>
+#include <unordered_map>
+#include <vector>
+
+//
+// final execution states (i.e. did anything go wrong..?)
+//
+enum class status_t {
+    SUCCESS = 0,
+    // mesh is malformed
+    // * vertices less than 3
+    // * no faces
+    // * non-manifold
+    // * contains more than one connected component
+    INVALID_SRC_MESH = -1, // TODO: these error flags should be generated in mcut.cpp not the kernel
+    INVALID_CUT_MESH = -2,
+    // EDGE_EDGE_INTERSECTION = -3, // Found an edge-edge intersection.
+    // FACE_VERTEX_INTERSECTION = -4, // Found an face-vertex intersection.
+
+    // there exists no edge in the input mesh which intersects cut-surface polygon
+    INVALID_MESH_INTERSECTION = -3,
+
+    // The bounding volume heirarchies of the input mesh and cut surface do not overlap
+    // INVALID_BVH_INTERSECTION = -6,
+    /*
+    MCUT is formulated for inputs in general position. Here the notion of general position is defined with
+    respect to the orientation predicate (as evaluated on the intersecting polygons). Thus, a set of points
+    is in general position if no three points are collinear and also no four points are coplanar.
+
+    MCUT uses the "GENERAL_POSITION_VIOLATION" flag to inform of when to use perturbation (of the
+    cut-mesh) so as to bring the input into general position. In such cases, the idea is to solve the cutting
+    problem not on the given input, but on a nearby input. The nearby input is obtained by perturbing the given
+    input. The perturbed input will then be in general position and, since it is near the original input,
+    the result for the perturbed input will hopefully still be useful.  This is justified by the fact that
+    the task of MCUT is not to decide whether the input is in general position but rather to make perturbation
+    on the input (if) necessary within the available precision of the computing device.
+*/
+    GENERAL_POSITION_VIOLATION = -4,
+    /*
+  TODO: add documentation
+*/
+    DETECTED_FLOATING_POLYGON = -5
+};
+
+//
+// Position of a cut surface patch with respect to the input mesh
+//
+enum class cm_patch_location_t : unsigned char {
+    INSIDE, // + : The patch is located inside the input mesh volume (i.e. it is used to seal holes)
+    OUTSIDE, // - : The patch is located outside the input mesh volume (boolean union).
+    UNDEFINED // ~ : The notion of INSIDE/OUTSIDE is not applicable because input mesh is non-watertight
+};
+
+//
+// Position of a connected component (CC) relative to cut-surface
+//
+enum class sm_frag_location_t : unsigned char {
+    ABOVE, // + : The CC is on positive side of the cut-surface (normal direction)
+    BELOW, // - :  The CC is on negative side of the cut-surface (normal direction)
+    UNDEFINED // ~ : The notion of ABOVE/BELOW is not applicable because the CC has [partially] cut
+};
+
+//
+// The winding order of the polygons of a cut surface patch
+//
+enum class cm_patch_winding_order_t : unsigned char {
+    DEFAULT, // + : The polygons of the patch have the [same] winding order as the cut-surface (e.g. CCW)
+    REVERSE, // - : The polygons of the patch have the [opposite] winding order as the cut-surface (e.g. CW)
+};
+
+struct floating_polygon_info_t {
+    // normal of polygon
+    vec3 polygon_normal;
+    int polygon_normal_largest_component = -1;
+    // the positions of the vertices of the floating polygon (order implies connectivity i.e. two points next to each other share a vertex)
+    std::vector<vec3> polygon_vertices;
+};
+
+//
+// settings for how to execute the function "dispatch(...)"
+//
+struct input_t {
+#if defined(MCUT_WITH_COMPUTE_HELPER_THREADPOOL)
+    thread_pool* scheduler = nullptr;
+#endif
+    /*const*/ std::shared_ptr<hmesh_t> src_mesh = nullptr;
+    /*const*/ std::shared_ptr<hmesh_t> cut_mesh = nullptr;
+    // NOTE: we use std::map because it is beneficial that keys are sorted when
+    // extracting edge-face intersection pairs
+    const std::map<fd_t, std::vector<fd_t>>* ps_face_to_potentially_intersecting_others = nullptr;
+#if defined(USE_OIBVH)
+    const std::vector<bounding_box_t<vec3>>* source_hmesh_face_aabb_array_ptr = nullptr;
+    const std::vector<bounding_box_t<vec3>>* cut_hmesh_face_aabb_array_ptr = nullptr;
+#else
+    BoundingVolumeHierarchy* source_hmesh_BVH;
+    BoundingVolumeHierarchy* cut_hmesh_BVH;
+#endif
+    bool verbose = true;
+    // bool keep_partially_sealed_connected_components = false;
+    bool require_looped_cutpaths = false; // ... i.e. bail on partial cuts (any!)
+    bool populate_vertex_maps = false; // compute data relating vertices in cc to original input mesh
+    bool populate_face_maps = false; // compute data relating face in cc to original input mesh
+    bool enforce_general_position = false;
+    // counts how many times we have perturbed the cut-mesh to enforce general-position
+    int general_position_enforcement_count = 0;
+
+    // NOTE TO SELF: if the user simply wants seams, then kernel should not have to proceed to stitching!!!
+    bool keep_srcmesh_seam = false;
+    bool keep_cutmesh_seam = false;
+    //
+    bool keep_unsealed_fragments = false;
+    //
+    bool keep_inside_patches = false;
+    bool keep_outside_patches = false;
+    //
+    bool keep_fragments_below_cutmesh = false;
+    bool keep_fragments_above_cutmesh = false;
+    //
+    bool keep_fragments_partially_cut = false; // TODO: remove
+    bool keep_fragments_sealed_inside = false;
+    bool keep_fragments_sealed_outside = false;
+    // bool include_fragment_sealed_partial = false; // See: variable above "keep_partially_sealed_connected_components"
+    bool keep_fragments_sealed_inside_exhaustive = false; // TODO remove
+    bool keep_fragments_sealed_outside_exhaustive = false; // TODO remove
+    // NOTE TO SELF: if the user simply wants patches, then kernel should not have to proceed to stitching!!!
+};
+
+struct output_mesh_data_maps_t {
+    // std::map<
+    //    vd_t, // vertex descriptor in connected component
+    //    vd_t // vertex descriptor in input-mesh e.g. source mesh or cut mesh. ("null_vertex()" if vertex is an intersection point)
+    //    >
+    std::vector<vd_t> vertex_map;
+    // std::map<
+    //     fd_t, // face descriptor in connected component
+    //     fd_t // face descriptor in input-mesh e.g. source mesh or cut mesh. (new polygons resulting from clipping are mapped to the same input mesh face)
+    //     >
+    std::vector<fd_t> face_map;
+};
+
+struct output_mesh_info_t {
+    std::shared_ptr<hmesh_t> mesh;
+    std::vector<vd_t> seam_vertices;
+    output_mesh_data_maps_t data_maps;
+};
+
+//
+// the output returned from the function "dispatch"
+//
+struct output_t {
+
+#if defined(MCUT_WITH_COMPUTE_HELPER_THREADPOOL)
+    std::atomic<status_t> status;
+#else
+    status_t status = status_t::SUCCESS;
+#endif
+
+    logger_t logger;
+    // fragments
+    std::map<sm_frag_location_t, std::map<cm_patch_location_t, std::vector<std::shared_ptr<output_mesh_info_t>>>> connected_components;
+    std::map<sm_frag_location_t, std::vector<std::shared_ptr<output_mesh_info_t>>> unsealed_cc; // connected components before hole-filling
+    // patches
+    std::map<cm_patch_winding_order_t, std::vector<std::shared_ptr<output_mesh_info_t>>> inside_patches; // .. between neigbouring connected ccsponents (cs-sealing patches)
+    std::map<cm_patch_winding_order_t, std::vector<std::shared_ptr<output_mesh_info_t>>> outside_patches;
+    // the input meshes which also include the edges that define the cut path
+    // NOTE: not always defined (depending on the arising cutpath configurations)
+    std::shared_ptr<output_mesh_info_t> seamed_src_mesh;
+    std::shared_ptr<output_mesh_info_t> seamed_cut_mesh;
+
+    // floating polygon handling
+    std::map<
+        // the face of the origin-mesh on which floating polygon(s) are discovered
+        // NOTE: this is a descriptor into the polygon soup. Thus, we'll need to
+        // subtract the number of source-mesh faces if this face belongs to the cut
+        // mesh.
+        fd_t,
+        // info about floating polygons contained on ps-face
+        std::vector<floating_polygon_info_t>>
+        detected_floating_polygons;
+};
+
+// internal main
+void dispatch(output_t& out, const input_t& in);
+
+int find_connected_components(
+#if defined(MCUT_WITH_COMPUTE_HELPER_THREADPOOL)
+    thread_pool& scheduler,
+#endif
+    std::vector<int>& fccmap, const hmesh_t& mesh, std::vector<int>& cc_to_vertex_count,
+    std::vector<int>& cc_to_face_count);
+
+// return true if point p lies on the plane of every three vertices of f
+bool point_on_face_plane(const hmesh_t& m, const fd_t& f, const vec3& p, int& fv_count);
+
+//
+// returns string equivalent value (e.g. for printing)
+//
+std::string to_string(const sm_frag_location_t&);
+std::string to_string(const cm_patch_location_t&);
+std::string to_string(const status_t&);
+std::string to_string(const cm_patch_winding_order_t&);
+
+#endif // #ifndef MCUT_KERNEL_H

src/mcut/include/mcut/internal/math.h

@@ -0,0 +1,695 @@
+/**
+ * Copyright (c) 2021-2022 Floyd M. Chitalu.
+ * All rights reserved.
+ *
+ * NOTE: This file is licensed under GPL-3.0-or-later (default).
+ * A commercial license can be purchased from Floyd M. Chitalu.
+ *
+ * License details:
+ *
+ * (A)  GNU General Public License ("GPL"); a copy of which you should have
+ *      recieved with this file.
+ * 	    - see also: <http://www.gnu.org/licenses/>
+ * (B)  Commercial license.
+ *      - email: floyd.m.chitalu@gmail.com
+ *
+ * The commercial license options is for users that wish to use MCUT in
+ * their products for comercial purposes but do not wish to release their
+ * software products under the GPL license.
+ *
+ * Author(s)     : Floyd M. Chitalu
+ */
+
+#ifndef MCUT_MATH_H_
+#define MCUT_MATH_H_
+
+#include <cmath>
+
+#include <iostream>
+#include <limits>
+#include <memory>
+
+#include <vector>
+
+#include "mcut/internal/utils.h"
+
+enum sign_t {
+    ON_NEGATIVE_SIDE = -1, // left
+    ON_ORIENTED_BOUNDARY = 0, // on boundary
+    ON_POSITIVE_SIDE = 1, // right
+    //
+    NEGATIVE = ON_NEGATIVE_SIDE,
+    ZERO = ON_ORIENTED_BOUNDARY,
+    POSITIVE = ON_POSITIVE_SIDE,
+};
+
+template <typename T = double>
+class vec2_ {
+public:
+    typedef T element_type;
+    vec2_()
+        : m_x(0.0)
+        , m_y(0.0)
+    {
+    }
+
+    vec2_(const T& value)
+        : m_x(value)
+        , m_y(value)
+    {
+    }
+
+    vec2_(const T& x, const T& y)
+        : m_x(x)
+        , m_y(y)
+    {
+    }
+
+    virtual ~vec2_()
+    {
+    }
+
+    static vec2_ make(const T x, const T y)
+    {
+        return vec2_<T>(x, y);
+    }
+
+    static int cardinality()
+    {
+        return 2;
+    }
+
+    bool operator==(const vec2_<T>& other) const
+    {
+        return this->m_x == other.x() && this->m_y == other.y();
+    }
+
+    const T& operator[](int index) const
+    {
+        MCUT_ASSERT(index >= 0 && index <= 1);
+
+        if (index == 0) {
+            return m_x;
+        } else {
+            return m_y;
+        }
+    }
+
+    T& operator[](int index)
+    {
+        MCUT_ASSERT(index >= 0 && index <= 1);
+
+        if (index == 0) {
+            return m_x;
+        } 
+
+            return m_y;
+        
+    }
+
+    const vec2_ operator-(const vec2_& other) const
+    {
+        return vec2_(m_x - other.m_x, m_y - other.m_y);
+    }
+
+    const vec2_ operator+(const vec2_& other) const
+    {
+        return vec2_(m_x + other.m_x, m_y + other.m_y);
+    }
+
+    const vec2_ operator/(const T& number) const
+    {
+        return vec2_(m_x / number, m_y / number);
+    }
+
+    const vec2_ operator*(const T& number) const
+    {
+        return vec2_(m_x * number, m_y * number);
+    }
+
+    const T& x() const
+    {
+        return m_x;
+    }
+
+    const T& y() const
+    {
+        return m_y;
+    }
+
+     T& x()  
+    {
+        return m_x;
+    }
+
+      T& y()  
+    {
+        return m_y;
+    }
+
+protected:
+    T m_x, m_y;
+}; // vec2_
+
+typedef vec2_<> vec2;
+
+template <typename T = double>
+class vec3_ : public vec2_<T> {
+public:
+    vec3_()
+        : vec2_<T>(0.0, 0.0)
+        , m_z(0.0)
+    {
+    }
+
+    vec3_(const T& value)
+        : vec2_<T>(value, value)
+        , m_z(value)
+    {
+    }
+
+    vec3_(const T& x, const T& y, const T& z)
+        : vec2_<T>(x, y)
+        , m_z(z)
+    {
+    }
+    ~vec3_()
+    {
+    }
+
+    static int cardinality()
+    {
+        return 3;
+    }
+
+    const T& operator[](int index) const
+    {
+        MCUT_ASSERT(index >= 0 && index <= 2);
+        if (index == 0) {
+            return this->m_x;
+        } else if (index == 1) {
+            return this->m_y;
+        } else {
+            return this->m_z;
+        }
+    }
+
+    T& operator[](int index)
+    {
+        MCUT_ASSERT(index >= 0 && index <= 2);
+        if (index == 0) {
+            return this->m_x;
+        } else if (index == 1) {
+            return this->m_y;
+        } else {
+            return this->m_z;
+        }
+    }
+
+    vec3_ operator-(const vec3_& other) const
+    {
+        return vec3_(this->m_x - other.m_x, this->m_y - other.m_y, this->m_z - other.m_z);
+    }
+
+    vec3_ operator+(const vec3_& other) const
+    {
+        return vec3_(this->m_x + other.m_x, this->m_y + other.m_y, this->m_z + other.m_z);
+    }
+
+    const vec3_ operator/(const T& number) const
+    {
+        return vec3_(this->m_x / number, this->m_y / number, this->m_z / number);
+    }
+
+    const vec3_ operator*(const T& number) const
+    {
+        return vec3_(this->m_x * number, this->m_y * number, this->m_z * number);
+    }
+
+    const T& z() const
+    {
+        return m_z;
+    }
+
+protected:
+    T m_z;
+}; // vec3_
+
+typedef vec3_<> vec3;
+
+template <typename T = int>
+class matrix_t {
+public:
+    matrix_t()
+        : m_rows(-1)
+        , m_cols(-1)
+    {
+    }
+
+    matrix_t(unsigned int rows, unsigned int cols)
+        : m_rows(rows)
+        , m_cols(cols)
+        , m_entries(std::vector<T>((size_t)rows * cols, T(0.0))) // zeroes
+    {
+    }
+
+    T& operator()(unsigned int row, unsigned int col)
+    {
+        return m_entries[(size_t)row * m_cols + col];
+    }
+
+    T operator()(unsigned int row, unsigned int col) const
+    {
+        return m_entries[(size_t)row * m_cols + col];
+    }
+
+    // multiply
+    matrix_t<T> operator*(const matrix_t<T>& other) const
+    {
+        matrix_t<T> result(this->rows(), other.cols());
+
+        for (int i = 0; i < this->rows(); ++i) {
+            for (int j = 0; j < other.cols(); ++j) {
+                for (int k = 0; k < this->cols(); ++k) {
+                    result(i, j) += (*this)(i, k) * other(k, j);
+                }
+            }
+        }
+
+        return result;
+    }
+
+    matrix_t<T> operator*(const double& s) const
+    {
+        matrix_t<T> result(m_rows, m_cols);
+
+        for (int i = 0; i < m_rows; ++i) {
+            for (int j = 0; j < m_cols; ++j) {
+                result(i, j) = (*this)(i, j) * s;
+            }
+        }
+
+        return result;
+    }
+
+    matrix_t<T> operator/(const double& s) const
+    {
+        matrix_t<T> result(m_rows, m_cols);
+
+        for (int i = 0; i < m_rows; ++i) {
+            for (int j = 0; j < m_cols; ++j) {
+                result(i, j) = (*this)(i, j) / s;
+            }
+        }
+
+        return result;
+    }
+
+    matrix_t<T> operator-(const matrix_t<T>& m) const
+    {
+        MCUT_ASSERT(m.rows() == this->rows());
+        MCUT_ASSERT(m.cols() == this->cols());
+
+        matrix_t<T> result(m_rows, m_cols);
+
+        for (int i = 0; i < m_rows; ++i) {
+            for (int j = 0; j < m_cols; ++j) {
+                result(i, j) = (*this)(i, j) - m(i, j);
+            }
+        }
+
+        return result;
+    }
+
+    // 2x3 matrix times 3x1 vector
+    vec2 operator*(const vec3& v) const
+    {
+        MCUT_ASSERT(this->cols() == vec3::cardinality());
+        vec2 result(double(0.0));
+        MCUT_ASSERT(this->rows() == vec2::cardinality());
+
+        for (int col = 0; col < this->cols(); ++col) {
+            for (int row = 0; row < vec2::cardinality(); ++row) {
+                result[row] = result[row] + ((*this)(row, col) * v[col]);
+            }
+        }
+#if 0
+        // columns
+        const Vec c0((*this)(0, 0), (*this)(1, 0), (*this)(2, 0));
+        const Vec c1((*this)(0, 1), (*this)(1, 1), (*this)(2, 1));
+
+        result = c0 * v[0] + c1 * v[1];
+
+        if (this->rows() == 3 && (this->cols() == 3)
+        {
+            const Vec c2((*this)(0, 2), (*this)(1, 2), (*this)(2, 2));
+            result = result + c2 * v[2];
+        }
+#endif
+        return result;
+    }
+
+    inline int rows() const
+    {
+        return m_rows;
+    }
+
+    inline int cols() const
+    {
+        return m_cols;
+    }
+
+private:
+    int m_rows;
+    int m_cols;
+    std::vector<T> m_entries;
+};
+
+extern double square_root(const double& number);
+extern double absolute_value(const double& number);
+extern sign_t sign(const double& number);
+extern std::ostream& operator<<(std::ostream& os, const vec3& v);
+
+template <typename U>
+std::ostream& operator<<(std::ostream& os, const matrix_t<U>& m)
+{
+    for (int i = 0; i < m.rows(); i++) {
+        for (int j = 0; j < m.cols(); j++) {
+            os << m(i, j) << ", ";
+        }
+        os << "\n";
+    }
+    return os;
+}
+
+template <typename T>
+const T& min(const T& a, const T& b)
+{
+    return ((b < a) ? b : a);
+}
+template <typename T>
+const T& max(const T& a, const T& b)
+{
+    return ((a < b) ? b : a);
+}
+
+extern bool operator==(const vec3& a, const vec3& b);
+
+template <typename T>
+vec2_<T> compwise_min(const vec2_<T>& a, const vec2_<T>& b)
+{
+    return vec2_<T>(min(a.x(), b.x()), min(a.y(), b.y()));
+}
+
+template <typename T>
+vec2_<T> compwise_max(const vec2_<T>& a, const vec2_<T>& b)
+{
+    return vec2_<T>(max(a.x(), b.x()), max(a.y(), b.y()));
+}
+
+template <typename T>
+vec3_<T> compwise_min(const vec3_<T>& a, const vec3_<T>& b)
+{
+    return vec3_<T>(min(a.x(), b.x()), min(a.y(), b.y()), min(a.z(), b.z()));
+}
+
+template <typename T>
+vec3_<T> compwise_max(const vec3_<T>& a, const vec3_<T>& b)
+{
+    return vec3_<T>(max(a.x(), b.x()), max(a.y(), b.y()), max(a.z(), b.z()));
+}
+
+extern vec3 cross_product(const vec3& a, const vec3& b);
+
+template <typename vector_type>
+double dot_product(const vector_type& a, const vector_type& b)
+{
+    double out(0.0);
+    for (int i = 0; i < vector_type::cardinality(); ++i) {
+        out += (a[i] * b[i]);
+    }
+    return out;
+}
+
+// compute a*b^T, which is a matrix
+template <typename vector_type>
+matrix_t<typename vector_type::element_type> outer_product(const vector_type& a, const vector_type& b)
+{
+    matrix_t<typename vector_type::element_type> out(vector_type::cardinality(), vector_type::cardinality());
+    const vector_type c0 = a * b[0]; // colmuns
+    const vector_type c1 = a * b[1];
+
+    if (vector_type::cardinality() == 3) {
+        const vector_type c2 = a * b[2];
+
+        out(0, 0) = c0[0];
+        out(1, 0) = c0[1];
+        out(2, 0) = c0[2];
+
+        out(0, 1) = c1[0];
+        out(1, 1) = c1[1];
+        out(2, 1) = c1[2];
+
+        out(0, 2) = c2[0];
+        out(1, 2) = c2[1];
+        out(2, 2) = c2[2];
+    } else {
+        out(0, 0) = c0[0];
+        out(1, 0) = c0[1];
+
+        out(0, 1) = c1[0];
+        out(1, 1) = c1[1];
+    }
+
+    return out;
+}
+
+template <typename vector_type>
+double squared_length(const vector_type& v)
+{
+    return dot_product(v, v);
+}
+
+template <typename vector_type>
+double length(const vector_type& v)
+{
+    return square_root(squared_length(v));
+}
+
+template <typename vector_type>
+vector_type normalize(const vector_type& v)
+{
+    return v / length(v);
+}
+
+double orient2d(const vec2& pa, const vec2& pb, const vec2& pc);
+double orient3d(const vec3& pa, const vec3& pb, const vec3& pc,
+    const vec3& pd);
+
+// Compute a polygon's plane coefficients (i.e. normal and d parameters).
+// The computed normal is not normalized. This function returns the largest component of the normal.
+int compute_polygon_plane_coefficients(vec3& normal, double& d_coeff,
+    const vec3* polygon_vertices, const int polygon_vertex_count);
+
+// Compute the intersection point between a line (not a segment) and a plane defined by a polygon.
+//
+// Parameters:
+//  'p' : output intersection point (computed if line does indeed intersect the plane)
+//  'q' : first point defining your line
+//  'r' : second point defining your line
+//  'polygon_vertices' : the vertices of the polygon defineing the plane (assumed to not be degenerate)
+//  'polygon_vertex_count' : number of olygon vertices
+//  'polygon_normal_max_comp' : largest component of polygon normal.
+//  'polygon_plane_normal' : normal of the given polygon
+//  'polygon_plane_d_coeff' : the distance coefficient of the plane equation corresponding to the polygon's plane
+//
+// Return values:
+// '0': line is parallel to plane or polygon is degenerate (within available precision)
+// '1': an intersection exists.
+// 'p': q and r lie in the plane (technically they are parallel to the plane too).
+char compute_line_plane_intersection(vec3& p, // intersection point
+    const vec3& q, const vec3& r, const vec3* polygon_vertices,
+    const int polygon_vertex_count, const int polygon_normal_max_comp,
+    const vec3& polygon_plane_normal);
+
+// Test if a line segment intersects with a plane, and yeild the intersection point if so.
+//
+// Return values:
+// 'p': The segment lies wholly within the plane.
+// 'q': The(first) q endpoint is on the plane (but not 'p').
+// 'r' : The(second) r endpoint is on the plane (but not 'p').
+// '0' : The segment lies strictly to one side or the other of the plane.
+// '1': The segment intersects the plane, and none of {p, q, r} hold.
+char compute_segment_plane_intersection(vec3& p, const vec3& normal, const double& d_coeff,
+    const vec3& q, const vec3& r);
+
+// Similar to "compute_segment_plane_intersection" but simply checks the [type] of intersection using
+// exact arithmetic
+//
+// Return values:
+// 'p': The segment lies wholly within the plane.
+// 'q': The(first) q endpoint is on the plane (but not 'p').
+// 'r' : The(second) r endpoint is on the plane (but not 'p').
+// '0' : The segment lies strictly to one side or the other of the plane.
+// '1': The segment intersects the plane, and none of {p, q, r} hold.
+char compute_segment_plane_intersection_type(const vec3& q, const vec3& r,
+    const std::vector<vec3>& polygon_vertices,
+    const vec3& polygon_normal, const int polygon_normal_largest_component);
+
+// Test if a point 'q' (in 2D) lies inside or outside a given polygon (count the number ray crossings).
+//
+// Return values:
+// 'i': q is strictly interior
+// 'o': q is strictly exterior (outside).
+// 'e': q is on an edge, but not an endpoint.
+// 'v': q is a vertex.
+char compute_point_in_polygon_test(const vec2& q, const std::vector<vec2>& polygon_vertices);
+
+// Test if a point 'q' (in 3D) lies inside or outside a given polygon (count the number ray crossings).
+//
+// Return values:
+// 'i': q is strictly interior
+// 'o': q is strictly exterior (outside).
+// 'e': q is on an edge, but not an endpoint.
+// 'v': q is a vertex.
+char compute_point_in_polygon_test(const vec3& p, const std::vector<vec3>& polygon_vertices,
+    const vec3& polygon_normal, const int polygon_normal_largest_component);
+
+// project a 3d polygon to 3d by eliminating the largest component of its normal
+void project_to_2d(std::vector<vec2>& out, const std::vector<vec3>& polygon_vertices,
+    const vec3& polygon_normal, const int polygon_normal_largest_component);
+
+void project_to_2d(std::vector<vec2>& out, const std::vector<vec3>& polygon_vertices,
+    const vec3& polygon_normal);
+
+bool coplaner(const vec3& pa, const vec3& pb, const vec3& pc,
+    const vec3& pd);
+
+bool collinear(const vec2& a, const vec2& b, const vec2& c, double& predResult);
+
+bool collinear(const vec2& a, const vec2& b, const vec2& c);
+
+/*
+Compute the intersection of two line segments. Can also be used to calculate where the respective lines intersect.
+
+Parameters:
+'a' and 'b': end points of first segment
+'c' and 'd': end points of second segment
+'p': the intersection point
+'s': the parameter for parametric equation of segment a,b (0..1)
+'t': the parameter for parametric equation of segment c,d (0..1)
+
+Return values:
+
+'e': The segments collinearly overlap, sharing a point; 'e' stands for 'edge.'
+'v': An endpoint of one segment is on the other segment, but 'e' doesn't hold; 'v' stands for 'vertex.'
+'1': The segments intersect properly (i.e., they share a point and neither 'v' nor 'e' holds); '1' stands for TRUE.
+'0': The segments do not intersect (i.e., they share no points); '0' stands for FALSE
+*/
+char compute_segment_intersection(const vec2& a, const vec2& b, const vec2& c, const vec2& d,
+    vec2& p, double& s, double& t);
+
+template <typename vector_type>
+struct bounding_box_t {
+
+    vector_type m_minimum;
+    vector_type m_maximum;
+
+    bounding_box_t(const vector_type& minimum, const vector_type& maximum)
+    {
+        m_minimum = minimum;
+        m_maximum = maximum;
+    }
+
+    bounding_box_t()
+    {
+        m_minimum = vector_type(std::numeric_limits<double>::max());
+        m_maximum = vector_type(-std::numeric_limits<double>::max());
+    }
+
+    inline const vector_type& minimum() const
+    {
+        return m_minimum;
+    }
+
+    inline const vector_type& maximum() const
+    {
+        return m_maximum;
+    }
+
+    inline void expand(const vector_type& point)
+    {
+        m_maximum = compwise_max(m_maximum, point);
+        m_minimum = compwise_min(m_minimum, point);
+    }
+
+    inline void expand(const bounding_box_t<vector_type>& bbox)
+    {
+        m_maximum = compwise_max(m_maximum, bbox.maximum());
+        m_minimum = compwise_min(m_minimum, bbox.minimum());
+    }
+
+    inline void enlarge(const typename vector_type::element_type& eps_)
+    {
+        m_maximum = m_maximum + eps_;
+        m_minimum = m_minimum - eps_;
+    }
+
+    float SurfaceArea() const
+    {
+        vector_type d = m_maximum - m_minimum;
+        return typename vector_type::element_type(2.0) * (d.x() * d.y() + d.x() * d.z() + d.y() * d.z());
+    }
+
+    int MaximumExtent() const
+    {
+        vector_type diag = m_maximum - m_minimum;
+        if (diag.x() > diag.y() && diag.x() > diag.z())
+            return 0;
+        else if (diag.y() > diag.z())
+            return 1;
+        else
+            return 2;
+    }
+};
+
+
+template <typename T>
+inline bool intersect_bounding_boxes(const bounding_box_t<vec3_<T>>& a, const bounding_box_t<vec3_<T>>& b)
+{
+    const vec3_<T>& amin = a.minimum();
+    const vec3_<T>& amax = a.maximum();
+    const vec3_<T>& bmin = b.minimum();
+    const vec3_<T>& bmax = b.maximum();
+    return (amin.x() <= bmax.x() && amax.x() >= bmin.x()) && //
+        (amin.y() <= bmax.y() && amax.y() >= bmin.y()) && //
+        (amin.z() <= bmax.z() && amax.z() >= bmin.z());
+}
+
+bool point_in_bounding_box(const vec2& point, const bounding_box_t<vec2>& bbox);
+
+bool point_in_bounding_box(const vec3& point, const bounding_box_t<vec3>& bbox);
+
+template <typename vector_type>
+void make_bbox(bounding_box_t<vector_type>& bbox, const vector_type* vertices, const int num_vertices)
+{
+    MCUT_ASSERT(vertices != nullptr);
+    MCUT_ASSERT(num_vertices >= 3);
+
+    for (int i = 0; i < num_vertices; ++i) {
+        const vector_type& vertex = vertices[i];
+        bbox.expand(vertex);
+    }
+}
+
+// Shewchuk predicates : shewchuk.c
+extern "C" {
+// void exactinit();
+double orient2d(const double* pa, const double* pb, const double* pc);
+double orient3d(const double* pa, const double* pb, const double* pc, const double* pd);
+double orient3dfast(const double* pa, const double* pb, const double* pc, const double* pd);
+double incircle(const double* pa, const double* pb, const double* pc, const double* pd);
+double insphere(const double* pa, const double* pb, const double* pc, const double* pd, const double* pe);
+}
+
+#endif // MCUT_MATH_H_

src/mcut/include/mcut/internal/preproc.h

@@ -0,0 +1,55 @@
+/**
+ * Copyright (c) 2021-2022 Floyd M. Chitalu.
+ * All rights reserved.
+ *
+ * NOTE: This file is licensed under GPL-3.0-or-later (default).
+ * A commercial license can be purchased from Floyd M. Chitalu.
+ *
+ * License details:
+ *
+ * (A)  GNU General Public License ("GPL"); a copy of which you should have
+ *      recieved with this file.
+ * 	    - see also: <http://www.gnu.org/licenses/>
+ * (B)  Commercial license.
+ *      - email: floyd.m.chitalu@gmail.com
+ *
+ * The commercial license options is for users that wish to use MCUT in
+ * their products for comercial purposes but do not wish to release their
+ * software products under the GPL license.
+ *
+ * Author(s)     : Floyd M. Chitalu
+ */
+
+/**
+ * @file mcut.h
+ * @author Floyd M. Chitalu
+ * @date 22 July 2022
+ *
+ * @brief API-function implementations.
+ *
+ * NOTE: This header file defines the frontend implementation of mcDispatch, 
+ * which handles mesh preparation (BVH building, traversal, polygon partitioning
+ * etc).
+ *
+ */
+
+#ifndef _FRONTEND_INTERSECT_H_
+#define _FRONTEND_INTERSECT_H_
+
+#include "mcut/internal/frontend.h"
+
+extern "C" void preproc(
+    std::shared_ptr<context_t> context_uptr,
+    McFlags dispatchFlags,
+    const void* pSrcMeshVertices,
+    const uint32_t* pSrcMeshFaceIndices,
+    const uint32_t* pSrcMeshFaceSizes,
+    uint32_t numSrcMeshVertices,
+    uint32_t numSrcMeshFaces,
+    const void* pCutMeshVertices,
+    const uint32_t* pCutMeshFaceIndices,
+    const uint32_t* pCutMeshFaceSizes,
+    uint32_t numCutMeshVertices,
+    uint32_t numCutMeshFaces) noexcept(false);
+
+#endif // #ifndef _FRONTEND_INTERSECT_H_

src/mcut/include/mcut/internal/timer.h

@@ -0,0 +1,87 @@
+/**
+ * Copyright (c) 2021-2022 Floyd M. Chitalu.
+ * All rights reserved.
+ *
+ * NOTE: This file is licensed under GPL-3.0-or-later (default).
+ * A commercial license can be purchased from Floyd M. Chitalu.
+ *
+ * License details:
+ *
+ * (A)  GNU General Public License ("GPL"); a copy of which you should have
+ *      recieved with this file.
+ * 	    - see also: <http://www.gnu.org/licenses/>
+ * (B)  Commercial license.
+ *      - email: floyd.m.chitalu@gmail.com
+ *
+ * The commercial license options is for users that wish to use MCUT in
+ * their products for comercial purposes but do not wish to release their
+ * software products under the GPL license.
+ *
+ * Author(s)     : Floyd M. Chitalu
+ */
+#ifndef MCUT_TIMER_H_
+#define MCUT_TIMER_H_
+
+#include <chrono>
+#include <map>
+#include <memory>
+#include <stack>
+#include <sstream>
+
+#include "mcut/internal/utils.h"
+#include "mcut/internal/tpool.h"
+
+//#define PROFILING_BUILD
+
+class mini_timer {
+    std::chrono::time_point<std::chrono::steady_clock> m_start;
+    const std::string m_name;
+    bool m_valid = true;
+
+public:
+    mini_timer(const std::string& name)
+        : m_start(std::chrono::steady_clock::now())
+        , m_name(name)
+    {
+    }
+
+    ~mini_timer()
+    {
+        if (m_valid) {
+            const std::chrono::time_point<std::chrono::steady_clock> now = std::chrono::steady_clock::now();
+            const std::chrono::milliseconds elapsed = std::chrono::duration_cast<std::chrono::milliseconds>(now - m_start);
+            unsigned long long elapsed_ = elapsed.count();
+            log_msg("[MCUT][PROF:" << std::this_thread::get_id() << "]: \"" << m_name << "\" ("<< elapsed_ << "ms)");
+        }
+    }
+    void set_invalid()
+    {
+        m_valid = false;
+    }
+};
+
+extern thread_local std::stack<std::unique_ptr<mini_timer>> g_thrd_loc_timerstack;
+
+#if defined(PROFILING_BUILD)
+
+#define TIMESTACK_PUSH(name) \
+    g_thrd_loc_timerstack.push(std::unique_ptr<mini_timer>(new mini_timer(name)))
+#define TIMESTACK_POP() \
+    g_thrd_loc_timerstack.pop()
+#define TIMESTACK_RESET()                                              \
+    while (!g_thrd_loc_timerstack.empty()) {        \
+        g_thrd_loc_timerstack.top()->set_invalid(); \
+        g_thrd_loc_timerstack.pop();                \
+    }
+#define SCOPED_TIMER(name) \
+    mini_timer _1mt(name)
+#else
+#define SCOPED_TIMER(name)
+#define TIMESTACK_PUSH(name)
+#define TIMESTACK_POP()
+#define TIMESTACK_RESET()
+#endif
+
+
+
+#endif

src/mcut/include/mcut/internal/utils.h

@@ -0,0 +1,258 @@
+/**
+ * Copyright (c) 2021-2022 Floyd M. Chitalu.
+ * All rights reserved.
+ *
+ * NOTE: This file is licensed under GPL-3.0-or-later (default).
+ * A commercial license can be purchased from Floyd M. Chitalu.
+ *
+ * License details:
+ *
+ * (A)  GNU General Public License ("GPL"); a copy of which you should have
+ *      recieved with this file.
+ * 	    - see also: <http://www.gnu.org/licenses/>
+ * (B)  Commercial license.
+ *      - email: floyd.m.chitalu@gmail.com
+ *
+ * The commercial license options is for users that wish to use MCUT in
+ * their products for comercial purposes but do not wish to release their
+ * software products under the GPL license.
+ *
+ * Author(s)     : Floyd M. Chitalu
+ */
+
+#ifndef MCUT_UTILS_H_
+#define MCUT_UTILS_H_
+
+// check if c++11 is supported
+#if __cplusplus >= 201103L || (defined(_MSC_VER) && _MSC_VER >= 1900)
+#define MCUT_CXX11_IS_SUPPORTED
+#elif !defined(__cplusplus) && !defined(_MSC_VER)
+typedef char couldnt_parse_cxx_standard[-1]; ///< Error: couldn't parse standard
+#endif
+
+#if defined(_WIN64) || defined(_WIN32)
+#define MCUT_BUILD_WINDOWS 1
+#elif defined(__APPLE__)
+#define MCUT_BUILD_APPLE 1
+#elif defined(__linux__) || defined(__unix__)
+#define MCUT_BUILD_LINUX 1
+#endif // #if defined(_WIN64) || defined(_WIN32)
+
+#define MCUT_MAKE_STRING__(s) #s
+#define MCUT_MAKE_STRING_(s) MCUT_MAKE_STRING__(s)
+
+#ifndef NDEBUG
+#define MCUT_DEBUG_BUILD 1
+#endif
+
+// debug macros
+#if defined(MCUT_DEBUG_BUILD)
+//
+// MCUT_DEBUG_BREAKPOINT
+//
+#if defined(MCUT_BUILD_WINDOWS)
+#define MCUT_DEBUG_BREAKPOINT_() __debugbreak()
+#else // #if defined(MCUT_BUILD_WINDOWS)
+#define MCUT_DEBUG_BREAKPOINT_() std::abort()
+#endif // #if defined(MCUT_BUILD_WINDOWS)
+
+//
+// MCUT_ASSERT
+//
+#define MCUT_ASSERT(a)                   \
+    do {                                 \
+        if (false == (a)) {              \
+            std::fprintf(stderr,         \
+                "Assertion failed: %s, " \
+                "%d at \'%s\'\n",        \
+                __FILE__,                \
+                __LINE__,                \
+                MCUT_MAKE_STRING_(a));   \
+            MCUT_DEBUG_BREAKPOINT_();    \
+        }                                \
+    } while (0)
+
+#define DEBUG_CODE_MASK(code) code
+#else // #if defined(MCUT_DEBUG_BUILD)
+//
+// MCUT_ASSERT
+//
+#define MCUT_ASSERT(a) // do nothing
+#define DEBUG_CODE_MASK(code) // do nothing
+#endif // #if defined(MCUT_DEBUG_BUILD)
+
+#include <fstream>
+#include <iostream>
+#include <sstream>
+
+#if MCUT_BUILD_WINDOWS
+#define EXCEPTION_THROWN throw()
+#else
+#define EXCEPTION_THROWN
+#endif
+
+#define PEDANTIC_SUBSCRIPT_ACCESS 1
+
+#if defined(PEDANTIC_SUBSCRIPT_ACCESS)
+#define SAFE_ACCESS(var, i) var.at(i)
+#else
+#define SAFE_ACCESS(var, i) var[i]
+#endif
+
+static inline int wrap_integer(int x, const int lo, const int hi)
+{
+    const int range_size = hi - lo + 1;
+
+    if (x < lo) {
+        x += range_size * ((lo - x) / range_size + 1);
+    }
+
+    return lo + (x - lo) % range_size;
+}
+
+class logger_t {
+
+    std::stringstream m_buffer;
+    bool m_verbose;
+    std::string m_prepend;
+    std::string m_reason_for_failure;
+
+public:
+    typedef std::ostream& (*ManipFn)(std::ostream&);
+    typedef std::ios_base& (*FlagsFn)(std::ios_base&);
+
+    logger_t()
+        : m_buffer()
+        , m_verbose(false)
+        , m_prepend()
+        , m_reason_for_failure()
+    {
+    }
+    logger_t(const logger_t& other) = delete;
+    logger_t& operator=(const logger_t& other) = delete;
+
+    ~logger_t()
+    {
+    }
+
+    std::string get_log_string()
+    {
+        return m_buffer.str();
+    }
+
+    void set_reason_for_failure(const std::string& msg)
+    {
+        if (m_reason_for_failure.empty()) // NOTE
+            m_reason_for_failure = msg;
+    }
+
+    std::string get_reason_for_failure()
+    {
+        std::string s(m_reason_for_failure); // copy
+        return s;
+    }
+
+    inline bool verbose()
+    {
+        return m_verbose;
+    }
+
+    inline void set_verbose(bool b)
+    {
+        m_verbose = b;
+    }
+
+    inline void reset()
+    {
+        m_prepend.clear();
+    }
+
+    inline void indent()
+    {
+        if (!verbose()) {
+            return;
+        }
+        m_prepend.append("  ");
+    }
+
+    inline void unindent()
+    {
+        if (!verbose()) {
+            return;
+        }
+        m_prepend.pop_back();
+        m_prepend.pop_back();
+    }
+
+    template <class T> // int, double, strings, etc
+    inline logger_t& operator<<(const T& output)
+    {
+        if (verbose()) {
+            m_buffer << output;
+        }
+        return *this;
+    }
+
+    inline logger_t& operator<<(ManipFn manip) /// endl, flush, setw, setfill, etc.
+    {
+        if (verbose()) {
+            manip(m_buffer);
+
+            if (manip == static_cast<ManipFn>(std::flush) || manip == static_cast<ManipFn>(std::endl)) {
+                this->flush();
+            }
+        }
+        return *this;
+    }
+
+    inline logger_t& operator<<(FlagsFn manip) /// setiosflags, resetiosflags
+    {
+        if (verbose()) {
+            manip(m_buffer);
+        }
+        return *this;
+    }
+
+    inline void flush()
+    {
+        if (!(verbose())) {
+            return;
+        }
+
+#if 0 // dump log to terminal [immediately]
+            std::cout << m_prepend << "::" << m_buffer.str();
+            m_buffer.str(std::string());
+            m_buffer.clear();
+#endif
+    }
+};
+template <typename T>
+struct pair : std::pair<T, T> {
+    pair(const T a, const T b)
+        : std::pair<T, T>(a < b ? a : b, a < b ? b : a)
+    {
+    }
+};
+
+template <typename T>
+pair<T> make_pair(const T a, const T b)
+{
+    return pair<T>(a, b);
+}
+
+
+
+// Threadsafe logging to console which prevents std::cerr from mixing strings when
+// concatenating with the operator<< multiple time per string, across multiple
+// threads.
+#define log_msg(msg_str)                     \
+    {                                        \
+        std::stringstream ss;                \
+        ss << msg_str << std::endl;          \
+        std::cerr << ss.str() << std::flush; \
+        }
+
+// used to marked/label unused function parameters to prevent warnings
+#define UNUSED(x) [&x] {}()
+
+#endif // MCUT_UTILS_H_

src/mcut/include/mcut/platform.h

@@ -0,0 +1,109 @@
+/**
+ * Copyright (c) 2021-2022 Floyd M. Chitalu.
+ * All rights reserved.
+ * 
+ * NOTE: This file is licensed under GPL-3.0-or-later (default). 
+ * A commercial license can be purchased from Floyd M. Chitalu. 
+ *  
+ * License details:
+ * 
+ * (A)  GNU General Public License ("GPL"); a copy of which you should have 
+ *      recieved with this file.
+ * 	    - see also: <http://www.gnu.org/licenses/>
+ * (B)  Commercial license.
+ *      - email: floyd.m.chitalu@gmail.com
+ * 
+ * The commercial license options is for users that wish to use MCUT in 
+ * their products for comercial purposes but do not wish to release their 
+ * software products under the GPL license. 
+ * 
+ * Author(s)     : Floyd M. Chitalu
+ */
+
+/**
+ * @file platform.h
+ * @author Floyd M. Chitalu
+ * @date 1 Jan 2021
+ * @brief File containing platform-specific types and definitions.
+ *
+ * This header file defines platform specific directives and integral type 
+ * declarations.
+ * Platforms should define these so that MCUT users call MCUT commands
+ * with the same calling conventions that the MCUT implementation expects.
+ *
+ * MCAPI_ATTR - Placed before the return type in function declarations.
+ *              Useful for C++11 and GCC/Clang-style function attribute syntax.
+ * MCAPI_CALL - Placed after the return type in function declarations.
+ *              Useful for MSVC-style calling convention syntax.
+ * MCAPI_PTR  - Placed between the '(' and '*' in function pointer types.
+ *
+ * Function declaration:  MCAPI_ATTR void MCAPI_CALL mcFunction(void);
+ * Function pointer type: typedef void (MCAPI_PTR *PFN_mcFunction)(void);
+ * 
+ */
+
+#ifndef MC_PLATFORM_H_
+#define MC_PLATFORM_H_
+
+#ifdef __cplusplus
+extern "C"
+{
+#endif // __cplusplus
+
+/** @file */
+
+#if defined(_WIN32)
+    
+#ifdef MCUT_SHARED_LIB
+
+#if defined(MCUT_EXPORT_SHARED_LIB_SYMBOLS)
+    //** Symbol visibilty */
+    #define MCAPI_ATTR __declspec(dllexport)
+#else
+    //** Symbol visibilty */
+    #define MCAPI_ATTR __declspec(dllimport)
+#endif
+
+#else // MCUT_SHARED_LIB
+
+    //** Symbol visibilty */
+#define MCAPI_ATTR
+
+#endif // MCUT_SHARED_LIB
+
+    //** Function calling convention */
+    #define MCAPI_CALL __stdcall
+    //** Function pointer-type declaration helper */
+    #define MCAPI_PTR  MCAPI_CALL
+#else // #if defined(_WIN32)
+    
+    //** Symbol visibilty */
+    #define MCAPI_ATTR __attribute__((visibility("default")))
+    //** Function calling convention */
+    #define MCAPI_CALL
+    //** Function pointer-type declaration helper */
+    #define MCAPI_PTR
+#endif // #if defined(_WIN32)
+
+#include <stddef.h> // standard type definitions
+
+#if !defined(MC_NO_STDINT_H)
+    #if defined(_MSC_VER) && (_MSC_VER < 1600)
+        typedef signed   __int8  int8_t;
+        typedef unsigned __int8  uint8_t;
+        typedef signed   __int16 int16_t;
+        typedef unsigned __int16 uint16_t;
+        typedef signed   __int32 int32_t;
+        typedef unsigned __int32 uint32_t;
+        typedef signed   __int64 int64_t;
+        typedef unsigned __int64 uint64_t;
+    #else
+        #include <stdint.h> //  integer types
+    #endif
+#endif // !defined(MC_NO_STDINT_H)
+
+#ifdef __cplusplus
+} // extern "C"
+#endif // __cplusplus
+
+#endif

src/mcut/source/math.cpp

@@ -0,0 +1,903 @@
+/**
+ * Copyright (c) 2021-2022 Floyd M. Chitalu.
+ * All rights reserved.
+ *
+ * NOTE: This file is licensed under GPL-3.0-or-later (default).
+ * A commercial license can be purchased from Floyd M. Chitalu.
+ *
+ * License details:
+ *
+ * (A)  GNU General Public License ("GPL"); a copy of which you should have
+ *      recieved with this file.
+ * 	    - see also: <http://www.gnu.org/licenses/>
+ * (B)  Commercial license.
+ *      - email: floyd.m.chitalu@gmail.com
+ *
+ * The commercial license options is for users that wish to use MCUT in
+ * their products for comercial purposes but do not wish to release their
+ * software products under the GPL license.
+ *
+ * Author(s)     : Floyd M. Chitalu
+ */
+
+#include "mcut/internal/math.h"
+#include <algorithm> // std::sort
+#include <cstdlib>
+#include <tuple> // std::make_tuple std::get<>
+
+
+    double square_root(const double& number)
+    {
+#if !defined(MCUT_WITH_ARBITRARY_PRECISION_NUMBERS)
+        return std::sqrt(number);
+#else
+        arbitrary_precision_number_t out(number);
+        mpfr_sqrt(out.get_mpfr_handle(), number.get_mpfr_handle(), arbitrary_precision_number_t::get_default_rounding_mode());
+        return out;
+#endif // #if !defined(MCUT_WITH_ARBITRARY_PRECISION_NUMBERS)
+    }
+
+    double absolute_value(const double& number)
+    {
+#if !defined(MCUT_WITH_ARBITRARY_PRECISION_NUMBERS)
+        return std::fabs(number);
+#else
+        double out(number);
+        mpfr_abs(out.get_mpfr_handle(), number.get_mpfr_handle(), arbitrary_precision_number_t::get_default_rounding_mode());
+        return out;
+#endif // #if defined(MCUT_WITH_ARBITRARY_PRECISION_NUMBERS)
+    }
+
+    sign_t sign(const double& number)
+    {
+#if !defined(MCUT_WITH_ARBITRARY_PRECISION_NUMBERS)
+        int s = (double(0) < number) - (number < double(0));
+        sign_t result = sign_t::ZERO;
+        if (s > 0) {
+            result = sign_t::POSITIVE;
+        } else if (s < 0) {
+            result = sign_t::NEGATIVE;
+        }
+        return result;
+#else
+        double out(number);
+        int s = mpfr_sgn(number.get_mpfr_handle());
+        sign_t result = sign_t::ZERO;
+        if (s > 0) {
+            result = sign_t::POSITIVE;
+        } else if (s < 0) {
+            result = sign_t::NEGATIVE;
+        }
+        return result;
+#endif // #if defined(MCUT_WITH_ARBITRARY_PRECISION_NUMBERS)
+    }
+
+    std::ostream& operator<<(std::ostream& os, const vec3& v)
+    {
+        return os << static_cast<double>(v.x()) << ", " << static_cast<double>(v.y()) << ", " << static_cast<double>(v.z());
+    }
+
+    bool operator==(const vec3& a, const vec3& b)
+    {
+        return (a.x() == b.x()) && (a.y() == b.y()) && (a.z() == b.z());
+    }
+
+    vec3 cross_product(const vec3& a, const vec3& b)
+    {
+        return vec3(
+            a.y() * b.z() - a.z() * b.y(),
+            a.z() * b.x() - a.x() * b.z(),
+            a.x() * b.y() - a.y() * b.x());
+    }
+
+    double orient2d(const vec2& pa, const vec2& pb, const vec2& pc)
+    {
+        const double pa_[2] = { static_cast<double>(pa.x()), static_cast<double>(pa.y()) };
+        const double pb_[2] = { static_cast<double>(pb.x()), static_cast<double>(pb.y()) };
+        const double pc_[2] = { static_cast<double>(pc.x()), static_cast<double>(pc.y()) };
+
+        return ::orient2d(pa_, pb_, pc_); // shewchuk predicate
+    }
+
+    double orient3d(const vec3& pa, const vec3& pb, const vec3& pc,
+        const vec3& pd)
+    {
+        const double pa_[3] = { static_cast<double>(pa.x()), static_cast<double>(pa.y()), static_cast<double>(pa.z()) };
+        const double pb_[3] = { static_cast<double>(pb.x()), static_cast<double>(pb.y()), static_cast<double>(pb.z()) };
+        const double pc_[3] = { static_cast<double>(pc.x()), static_cast<double>(pc.y()), static_cast<double>(pc.z()) };
+        const double pd_[3] = { static_cast<double>(pd.x()), static_cast<double>(pd.y()), static_cast<double>(pd.z()) };
+
+        return ::orient3d(pa_, pb_, pc_, pd_); // shewchuk predicate
+    }
+
+#if 0
+    void polygon_normal(vec3& normal, const vec3* vertices, const int num_vertices)
+    {
+      normal = vec3(0.0);
+      for (int i = 0; i < num_vertices; ++i) {
+        normal = normal + cross_product(vertices[i] - vertices[0], vertices[(i + 1) % num_vertices] - vertices[0]);
+      }
+      normal = normalize(normal);
+    }
+#endif
+
+    int compute_polygon_plane_coefficients(vec3& normal, double& d_coeff,
+        const vec3* polygon_vertices, const int polygon_vertex_count)
+    {
+        // compute polygon normal (http://cs.haifa.ac.il/~gordon/plane.pdf)
+        normal = vec3(0.0);
+        for (int i = 0; i < polygon_vertex_count - 1; ++i) {
+            normal = normal + cross_product(polygon_vertices[i] - polygon_vertices[0], polygon_vertices[(i + 1) % polygon_vertex_count] - polygon_vertices[0]);
+        }
+
+        // In our calculations we need the normal be be of unit length so that the d-coeff
+        // represents the distance of the plane from the origin
+        // normal = normalize(normal);
+
+        d_coeff = dot_product(polygon_vertices[0], normal);
+
+        double largest_component(0.0);
+        double tmp(0.0);
+        int largest_component_idx = 0;
+
+        for (int i = 0; i < 3; ++i) {
+            tmp = absolute_value(normal[i]);
+            if (tmp > largest_component) {
+                largest_component = tmp;
+                largest_component_idx = i;
+            }
+        }
+
+        return largest_component_idx;
+    }
+
+    // Intersect a line segment with a plane
+    //
+    // Return values:
+    // 'p': The segment lies wholly within the plane.
+    // 'q': The(first) q endpoint is on the plane (but not 'p').
+    // 'r' : The(second) r endpoint is on the plane (but not 'p').
+    // '0' : The segment lies strictly to one side or the other of the plane.
+    // '1': The segment intersects the plane, and none of {p, q, r} hold.
+    char compute_segment_plane_intersection(vec3& p, const vec3& normal, const double& d_coeff,
+        const vec3& q, const vec3& r)
+    {
+
+        // vec3 planeNormal;
+        // double planeDCoeff;
+        // planeNormalLargestComponent = compute_polygon_plane_coefficients(planeNormal, planeDCoeff, polygonVertices,
+        // polygonVertexCount);
+
+        double num = d_coeff - dot_product(q, normal);
+        const vec3 rq = (r - q);
+        double denom = dot_product(rq, normal);
+
+        if (denom == double(0.0) /* Segment is parallel to plane.*/) {
+            if (num == double(0.0)) { // 'q' is on plane.
+                return 'p'; // The segment lies wholly within the plane
+            } else {
+                return '0';
+            }
+        }
+
+        double t = num / denom;
+
+        for (int i = 0; i < 3; ++i) {
+            p[i] = q[i] + t * (r[i] - q[i]);
+        }
+
+        if ((double(0.0) < t) && (t < double(1.0))) {
+            return '1'; // The segment intersects the plane, and none of {p, q, r} hold
+        } else if (num == double(0.0)) // t==0
+        {
+            return 'q'; // The (first) q endpoint is on the plane (but not 'p').
+        } else if (num == denom) // t==1
+        {
+            return 'r'; // The (second) r endpoint is on the plane (but not 'p').
+        } else {
+            return '0'; // The segment lies strictly to one side or the other of the plane
+        }
+    }
+
+    bool determine_three_noncollinear_vertices(int& i, int& j, int& k, const std::vector<vec3>& polygon_vertices,
+
+        const vec3& polygon_normal, const int polygon_normal_largest_component)
+    {
+        const int polygon_vertex_count = (int)polygon_vertices.size();
+        MCUT_ASSERT(polygon_vertex_count >= 3);
+
+        std::vector<vec2> x;
+        project_to_2d(x, polygon_vertices, polygon_normal, polygon_normal_largest_component);
+        MCUT_ASSERT(x.size() == (size_t)polygon_vertex_count);
+
+        /*
+            NOTE: We cannot just use _any_/the first result of "colinear(x[i], x[j], x[k])" which returns true since
+            any three points that are _nearly_ colinear (in the limit of floating point precision)
+            will be found to be not colinear when using the exact predicate "orient2d".
+            This would have implications "further down the line", where e.g. the three nearly colinear points
+            are determined to be non-colinear (in the exact sense) but using them to evaluate
+            operations like segment-plane intersection would then give a false positive.
+            To overcome this, must find the three vertices of the polygon, which maximise non-colinearity.
+
+            NOTE: if the polygon has 3 vertices and they are indeed nearly colinear then answer is determined by the
+            exact predicate (i.e. i j k = 0 1 2)
+        */
+
+        // get any three vertices that are not collinear
+        i = 0;
+        j = i + 1;
+        k = j + 1;
+        std::vector<std::tuple<int, int, int, double>> non_colinear_triplets;
+
+        for (; i < polygon_vertex_count; ++i) {
+            for (; j < polygon_vertex_count; ++j) {
+                for (; k < polygon_vertex_count; ++k) {
+                    double predRes;
+                    if (!collinear(x[i], x[j], x[k], predRes)) {
+                        non_colinear_triplets.emplace_back(std::make_tuple(i, j, k, predRes));
+                    }
+                }
+            }
+        }
+
+        std::sort(non_colinear_triplets.begin(), non_colinear_triplets.end(),
+            [](const std::tuple<int, int, int, double>& a, const std::tuple<int, int, int, double>& b) {
+                return std::fabs(std::get<3>(a)) > std::fabs(std::get<3>(b));
+            });
+
+        std::tuple<int, int, int, double> best_triplet = non_colinear_triplets.front(); // maximising non-colinearity
+
+        i = std::get<0>(best_triplet);
+        j = std::get<1>(best_triplet);
+        k = std::get<2>(best_triplet);
+
+        return !non_colinear_triplets.empty(); // need at least one non-colinear triplet
+    }
+
+    char compute_segment_plane_intersection_type(const vec3& q, const vec3& r,
+        const std::vector<vec3>& polygon_vertices,
+        const vec3& polygon_normal,
+        const int polygon_normal_largest_component)
+    {
+        // TODO: we could also return i,j and k so that "determine_three_noncollinear_vertices" is not called multiple times,
+        // which we do to determine the type of intersection and the actual intersection point
+        const int polygon_vertex_count = (int)polygon_vertices.size();
+        // ... any three vertices that are not collinear
+        int i = 0;
+        int j = 1;
+        int k = 2;
+        if (polygon_vertex_count > 3) { // case where we'd have the possibility of noncollinearity
+            bool b = determine_three_noncollinear_vertices(i, j, k, polygon_vertices, polygon_normal,
+                polygon_normal_largest_component);
+
+            if (!b) {
+                return '0'; // all polygon points are collinear
+            }
+        }
+
+        double qRes = orient3d(polygon_vertices[i], polygon_vertices[j], polygon_vertices[k], q);
+        double rRes = orient3d(polygon_vertices[i], polygon_vertices[j], polygon_vertices[k], r);
+
+        if (qRes == double(0.0) && rRes == double(0.0)) {
+            return 'p';
+        } else if (qRes == double(0.0)) {
+            return 'q';
+        } else if (rRes == double(0.0)) {
+            return 'r';
+        } else if ((rRes < double(0.0) && qRes < double(0.0)) || (rRes > double(0.0) && qRes > double(0.0))) {
+            return '0';
+        } else {
+            return '1';
+        }
+    }
+
+    char compute_segment_line_plane_intersection_type(const vec3& q, const vec3& r,
+        const std::vector<vec3>& polygon_vertices,
+
+        const int polygon_normal_max_comp,
+        const vec3& polygon_plane_normal)
+    {
+        const int polygon_vertex_count = (int)polygon_vertices.size();
+        // ... any three vertices that are not collinear
+        int i = 0;
+        int j = 1;
+        int k = 2;
+        if (polygon_vertex_count > 3) { // case where we'd have the possibility of noncollinearity
+            bool b = determine_three_noncollinear_vertices(i, j, k, polygon_vertices, polygon_plane_normal,
+                polygon_normal_max_comp);
+
+            if (!b) {
+                return '0'; // all polygon points are collinear
+            }
+        }
+
+        double qRes = orient3d(polygon_vertices[i], polygon_vertices[j], polygon_vertices[k], q);
+        double rRes = orient3d(polygon_vertices[i], polygon_vertices[j], polygon_vertices[k], r);
+
+        if (qRes == double(0.0) && rRes == double(0.0)) {
+            // both points used to define line lie on plane therefore we have an in-plane intersection
+            // or the polygon is a degenerate triangle
+            return 'p';
+        } else {
+            if ((rRes < double(0.0) && qRes < double(0.0)) || (rRes > double(0.0) && qRes > double(0.0))) { // both points used to define line lie on same side of plane
+                // check if line is parallel to plane
+                // const double num = polygon_plane_d_coeff - dot_product(q, polygon_plane_normal);
+                const vec3 rq = (r - q);
+                const double denom = dot_product(rq, polygon_plane_normal);
+
+                if (denom == double(0.0) /* Segment is parallel to plane.*/) {
+                    // MCUT_ASSERT(num != 0.0); // implies 'q' is on plane (see: "compute_segment_plane_intersection(...)")
+                    // but we have already established that q and r are on same side.
+                    return '0';
+                }
+            }
+        }
+
+        // q and r are on difference sides of the plane, therefore we have an intersection
+        return '1';
+    }
+
+    // Compute the intersection point between a line (not a segment) and a plane defined by a polygon.
+    //
+    // Parameters:
+    //  'p' : output intersection point (computed if line does indeed intersect the plane)
+    //  'q' : first point defining your line
+    //  'r' : second point defining your line
+    //  'polygon_vertices' : the vertices of the polygon defineing the plane (assumed to not be degenerate)
+    //  'polygon_vertex_count' : number of olygon vertices
+    //  'polygon_normal_max_comp' : largest component of polygon normal.
+    //  'polygon_plane_normal' : normal of the given polygon
+    //  'polygon_plane_d_coeff' : the distance coefficient of the plane equation corresponding to the polygon's plane
+    //
+    // Return values:
+    // '0': line is parallel to plane (or polygon is degenerate ... within available precision)
+    // '1': an intersection exists.
+    // 'p': q and r lie in the plane (technically they are parallel to the plane too but we need to report this because it
+    // violates GP).
+    char compute_line_plane_intersection(vec3& p, // intersection point
+        const vec3& q, const vec3& r,
+        const std::vector<vec3>& polygon_vertices, const int polygon_normal_max_comp,
+        const vec3& polygon_plane_normal,
+        const double& polygon_plane_d_coeff)
+    {
+
+        const int polygon_vertex_count = (int)polygon_vertices.size();
+        // ... any three vertices that are not collinear
+        int i = 0;
+        int j = 1;
+        int k = 2;
+        if (polygon_vertex_count > 3) { // case where we'd have the possibility of noncollinearity
+            bool b = determine_three_noncollinear_vertices(i, j, k, polygon_vertices, polygon_plane_normal,
+                polygon_normal_max_comp);
+
+            if (!b) {
+                return '0'; // all polygon points are collinear
+            }
+        }
+
+        double qRes = orient3d(polygon_vertices[i], polygon_vertices[j], polygon_vertices[k], q);
+        double rRes = orient3d(polygon_vertices[i], polygon_vertices[j], polygon_vertices[k], r);
+
+        if (qRes == double(0.) && rRes == double(0.)) {
+            return 'p'; // both points used to define line lie on plane therefore we have an in-plane intersection
+        } else {
+
+            const double num = polygon_plane_d_coeff - dot_product(q, polygon_plane_normal);
+            const vec3 rq = (r - q);
+            const double denom = dot_product(rq, polygon_plane_normal);
+
+            if ((rRes < double(0.) && qRes < double(0.)) || (rRes > double(0.) && qRes > double(0.))) { // both q an r are on same side of plane
+                if (denom == double(0.) /* line is parallel to plane.*/) {
+                    return '0';
+                }
+            }
+
+            // q and r are on difference sides of the plane, therefore we have an intersection
+
+            // compute the intersection point
+            const double t = num / denom;
+
+            for (int it = 0; it < 3; ++it) {
+                p[it] = q[it] + t * (r[it] - q[it]);
+            }
+
+            return '1';
+        }
+    }
+
+    // Count the number ray crossings to determine if a point 'q' lies inside or outside a given polygon.
+    //
+    // Return values:
+    // 'i': q is strictly interior
+    // 'o': q is strictly exterior (outside).
+    // 'e': q is on an edge, but not an endpoint.
+    // 'v': q is a vertex.
+    char compute_point_in_polygon_test(const vec2& q, const std::vector<vec2>& polygon_vertices)
+    {
+        const int polygon_vertex_count = (int)polygon_vertices.size();
+
+#if 0 // Algorithm 1 in :
+      // https://pdf.sciencedirectassets.com/271512/1-s2.0-S0925772100X00545/1-s2.0-S0925772101000128/main.pdf?X-Amz-Security-Token=IQoJb3JpZ2luX2VjEAEaCXVzLWVhc3QtMSJHMEUCIBr6Fu%2F%2FtscErn%2Fl4pn2UGNA45sAw9vggQscK7Tnl0ssAiEAzfnyy4B4%2BXkZp8xcEk7utDBrxgmGyH7pyqk0efKOUEoq%2BgMIKhAEGgwwNTkwMDM1NDY4NjUiDHQT4kOfk4%2B6kBB0xCrXAzd8SWlnELJbM5l93HSvv4nUgtO85%2FGyx5%2BOoHmYoUuVwJjCXChmLJmlz%2BxYUQE%2Fr8vQa2hPlUEPfiTVGgoHaK8NkSMP6LRs%2F3WjyZ9OxzHbqSwZixNceW34OAkq0E1QgYLdGVjpPKxNK1haXDfBTMN6bF2IOU9dKi9wTv3uTlep0kHDa1BNNl6M6yZk5QlF2bPF9XmNjjZCpFQLhr%2BPoHo%2Bx4xy39aH8hCkkTqGdy2KrKGN6lv0%2FduIaItyZfqalYS%2BwW6cll2F5G11g0tSu7yKu6mug94LUTzsRmzD0UhzeGl2WV6Ev2qhw26mwFEKgnTMqGst8XAHjFjjAQyMzXNHCQqNBRIevHIzVWuUY4QZMylSRsodo0dfwwCFhzl0%2BJA1ZXb0%2BoyB8c11meQBO8FpMSshngNcbiAYUtIOFcHNCTCUMk0JPOZ%2FxvANsopnivbrPARL71zU4PaTujg5jfC2zoO6ZDUL8E6Vn%2BNtfb%2BuQV7DwtIH51Bv%2F%2F1m6h5mjbpRiGYcH%2F5SDD%2Fk%2BpHfKRQzKu7jJc%2B0XO0bQvoLSrAte0Qk10PwOvDl5jMIMdmxTBDDiDGErRykYxMQhq5EwjyiWPXzM3ll9uK59Vy0bAEj5Qemj5by1jCDht6IBjqlAV4okAPQO5wWdWojCYeKvluKfXCvudrUxrLhsxb7%2BTZNMODTG%2Fn%2Fbw875Yr6fOQ42u40pOsnPB%2FTP3cWwjiB%2BEHzDqN8AhCVQyoedw7QrU3OBWlSl6lB%2BGLAVqrhcizgFUiM2nj3HaVP2m7S%2FXqpv%2FoWlEXt4gR8iI9XsIlh6L6SBE22FqbsU5ewCxXaqip19VXhAGnlvjTihXUg6yZGWhExHj%2BKcA%3D%3D&X-Amz-Algorithm=AWS4-HMAC-SHA256&X-Amz-Date=20210814T103958Z&X-Amz-SignedHeaders=host&X-Amz-Expires=300&X-Amz-Credential=ASIAQ3PHCVTY3PPQSW2L%2F20210814%2Fus-east-1%2Fs3%2Faws4_request&X-Amz-Signature=94403dce5c12ede9507e9612c000db5772607e59a2134d30d4e5b44212056dc7&hash=cada083b165f9786e6042e21d3d22147ec08b1e2c8fa2572ceeb2445cb5e730a&host=68042c943591013ac2b2430a89b270f6af2c76d8dfd086a07176afe7c76c2c61&pii=S0925772101000128&tid=spdf-f9e7c4b7-808d-4a8e-a474-6430ff687798&sid=8dddff5b32fff2499908bf6501965aec3d0fgxrqb&type=client
+
+            const double zero(0.0);
+            int i = 0;
+            int k = 0;
+
+            double f = zero;
+            double u1 = 0.0;
+            double v1 = 0.0;
+            double u2 = 0.0;
+            double v2 = 0.0;
+            const int n = polygon_vertex_count;
+            for (i = 0; i < n; ++i)
+            {
+                v1 = polygon_vertices[i].y() - q.y();
+                v2 = polygon_vertices[(i + 1) % n].y() - q.y();
+
+                if ((v1 < zero && v2 < zero) || (v1 > zero && v2 > zero))
+                {
+                    continue;
+                }
+
+                u1 = polygon_vertices[i].x() - q.x();
+                u2 = polygon_vertices[(i + 1) % n].x() - q.x();
+
+                if (v2 > zero && v1 <= zero)
+                {
+                    f = u1 * v2 - u2 * v1;
+                    if (f > zero)
+                    {
+                        k = k + 1;
+                    }
+                    else if (f == zero)
+                    {
+                        return 'e'; //-1; // boundary
+                    }
+                }
+                else if (v1 > zero && v2 <= zero)
+                {
+                    f = u1 * v2 - u2 * v1;
+                    if (f < zero)
+                    {
+                        k = k + 1;
+                    }
+                    else if (f == zero)
+                    {
+                        return 'e'; //-1; // boundary
+                    }
+                }
+                else if (v2 == zero && v1 < zero)
+                {
+                    f = u1 * v2 - u2 * v1;
+                    if (f == zero)
+                    {
+                        return 'e'; //-1; // // boundary
+                    }
+                }
+                else if (v1 == zero && v2 < zero)
+                {
+                    f = u1 * v2 - u2 * v1;
+                    if (f == zero)
+                    {
+                        return 'e'; //-1; // boundary
+                    }
+                }
+                else if (v1 == zero && v2 == zero)
+                {
+                    if (u2 <= zero && u1 >= zero)
+                    {
+                        return 'e'; //-1; // boundary
+                    }
+                    else if (u1 <= zero && u2 >= zero)
+                    {
+                        return 'e'; //-1; // boundary
+                    }
+                }
+            }
+            if (k % 2 == 0)
+            {
+                return 'o'; //0; // outside
+            }
+            else
+            {
+                return 'i'; //1; // inside
+            }
+#else // http://www.science.smith.edu/~jorourke/books/compgeom.html
+
+        std::vector<vec2> vertices(polygon_vertex_count, vec2());
+        // Shift so that q is the origin. Note this destroys the polygon.
+        // This is done for pedagogical clarity.
+        for (int i = 0; i < polygon_vertex_count; i++) {
+            for (int d = 0; d < 2; d++) {
+                const double& a = polygon_vertices[i][d];
+                const double& b = q[d];
+                double& c = vertices[i][d];
+                c = a - b;
+            }
+        }
+
+        int Rcross = 0; /* number of right edge/ray crossings */
+        int Lcross = 0; /* number ofleft edge/ray crossings */
+
+        /* For each edge e = (i<>lj), see if crosses ray. */
+        for (int i = 0; i < polygon_vertex_count; i++) {
+
+            /* First check if q = (0, 0) is a vertex. */
+            if (vertices[i].x() == double(0.) && vertices[i].y() == double(0.)) {
+                return 'v';
+            }
+
+            int il = (i + polygon_vertex_count - 1) % polygon_vertex_count;
+
+            // Check if e straddles x axis, with bias above/below.
+
+            // Rstrad is TRUE iff one endpoint of e is strictly above the x axis and the other is not (i.e., the other is on
+            // or below)
+            bool Rstrad = (vertices[i].y() > double(0.)) != (vertices[il].y() > double(0.));
+            bool Lstrad = (vertices[i].y() < double(0.)) != (vertices[il].y() < double(0.));
+
+            if (Rstrad || Lstrad) {
+                /* Compute intersection of e with x axis. */
+
+                // The computation of x is needed whenever either of these straddle variables is TRUE, which
+                // only excludes edges passing through q = (0, 0) (and incidentally protects against division by 0).
+                double x = (vertices[i].x() * vertices[il].y() - vertices[il].x() * vertices[i].y()) / (vertices[il].y() - vertices[i].y());
+                if (Rstrad && x > double(0.)) {
+                    Rcross++;
+                }
+                if (Lstrad && x < double(0.)) {
+                    Lcross++;
+                }
+            } /* end straddle computation*/
+        } // end for
+
+        /* q on an edge if L/Rcross counts are not the same parity.*/
+        if ((Rcross % 2) != (Lcross % 2)) {
+            return 'e';
+        }
+
+        /* q inside iff an odd number of crossings. */
+        if ((Rcross % 2) == 1) {
+            return 'i';
+        } else {
+            return 'o';
+        }
+#endif
+    }
+
+    // given a normal vector (not necessarily normalized) and its largest component, calculate
+    // a matrix P that will project any 3D vertex to 2D by removing the 3D component that
+    // corresponds to the largest component of the normal..
+    // https://math.stackexchange.com/questions/180418/calculate-rotation-matrix-to-align-vector-a-to-vector-b-in-3d/2672702#2672702
+    matrix_t<double> calculate_projection_matrix(const vec3& polygon_normal,
+        const int polygon_normal_largest_component)
+    {
+        MCUT_ASSERT(squared_length(polygon_normal) > double(0.0));
+        MCUT_ASSERT(polygon_normal_largest_component >= 0);
+        MCUT_ASSERT(polygon_normal_largest_component <= 2);
+
+        // unit length normal vector of polygon
+        const vec3 a = normalize(polygon_normal);
+        // unit length basis vector corresponding to the largest component of the normal vector
+        const vec3 b = [&]() {
+            vec3 x(double(0.0));
+            const sign_t s = sign(polygon_normal[polygon_normal_largest_component]);
+            MCUT_ASSERT(s != sign_t::ZERO); // implies that the normal vector has a magnitude of zero
+            // The largest component of the normal is the one we will "remove"
+            // NOTE: we multiple by the sign here to ensure that "a_plus_b" below is not zero when a == b
+            x[polygon_normal_largest_component] = double((1.0) * static_cast<long double>(s));
+            return x;
+        }();
+
+        matrix_t<double> I(3, 3); // 3x3 identity with reflection
+        I(0, 0) = 1.0;
+        I(1, 1) = -1.0;
+        I(2, 2) = 1.0;
+
+        matrix_t<double> R = I;
+
+        // NOTE: While this will map vectors a to b, it can add a lot of unnecessary "twist".
+        // For example, if a=b=e_{z} this formula will produce a 180-degree rotation about the z-axis rather
+        // than the identity one might expect.
+        if ((a[0] != b[0]) || (a[1] != b[1]) || (a[2] != b[2])) // a != b
+        {
+            const vec3 a_plus_b = a + b;
+            const double a_dot_b = dot_product(a, b);
+
+            // this will never be zero because we set 'b' as the canonical basis vector
+            // that has the largest projection onto the normal
+            MCUT_ASSERT(a_dot_b != double(0.0));
+
+            const matrix_t<double> outer = outer_product(a_plus_b, a_plus_b);
+
+            // compute the 3x3 rotation matrix R to orient the polygon into the canonical axes "i" and "j",
+            //  where "i" and "j" != "polygon_normal_largest_component"
+            R = ((outer / a_dot_b) * 2.0) - I; // rotation
+        }
+
+        // compute the 2x3 selector matrix K to select the polygon-vertex components that correspond
+        // to canonical axes "i" and "j".
+        matrix_t<double> K = matrix_t<double>(2, 3);
+
+        if (polygon_normal_largest_component == 0) // project by removing x-component
+        {
+            // 1st row
+            K(0, 0) = 0.0; // col 0
+            K(0, 1) = 1.0; // col 1
+            K(0, 2) = 0.0; // col 2
+            // 2nd row
+            K(1, 0) = 0.0; // col 0
+            K(1, 1) = 0.0; // col 1
+            K(1, 2) = 1.0; // col 2
+        } else if (polygon_normal_largest_component == 1) // project by removing y-component
+        {
+            // 1st row
+            K(0, 0) = 1.0; // col 0
+            K(0, 1) = 0.0; // col 1
+            K(0, 2) = 0.0; // col 2
+            // 2nd row
+            K(1, 0) = 0.0; // col 0
+            K(1, 1) = 0.0; // col 1
+            K(1, 2) = 1.0; // col 2
+        } else if (polygon_normal_largest_component == 2) // project by removing z-component
+        {
+            // 1st row
+            K(0, 0) = 1.0; // col 0
+            K(0, 1) = 0.0; // col 1
+            K(0, 2) = 0.0; // col 2
+            // 2nd row
+            K(1, 0) = 0.0; // col 0
+            K(1, 1) = 1.0; // col 1
+            K(1, 2) = 0.0; // col 2
+        }
+
+        return K * R;
+    }
+
+    // https://answers.unity.com/questions/1522620/converting-a-3d-polygon-into-a-2d-polygon.html
+    void project_to_2d(std::vector<vec2>& out, const std::vector<vec3>& polygon_vertices, const vec3& polygon_normal)
+    {
+        const uint32_t N = polygon_vertices.size();
+        out.resize(N);
+
+        const vec3 normal = normalize(polygon_normal);
+
+        // first unit vector on plane (rotation by 90 degrees)
+        vec3 u(-normal.y(), normal.x(), normal.z());
+        vec3 v = normalize(cross_product(u, normal));
+
+        for(uint32_t i =0; i < N; ++i)
+        {
+            const vec3 point = polygon_vertices[i];
+            const vec2 projected(
+                dot_product(point, u),
+                dot_product(point, v)
+            );
+
+            out[i] = projected;
+        }
+    }
+
+    void project_to_2d(std::vector<vec2>& out, const std::vector<vec3>& polygon_vertices,
+        const vec3& polygon_normal, const int polygon_normal_largest_component)
+    {
+        const int polygon_vertex_count = (int)polygon_vertices.size();
+        out.clear();
+        out.resize(polygon_vertex_count);
+
+#if 1
+        // 3x3 matrix for projecting a point to 2D
+        matrix_t<double> P = calculate_projection_matrix(polygon_normal, polygon_normal_largest_component);
+        for (int i = 0; i < polygon_vertex_count; ++i) { // for each vertex
+            const vec3& x = polygon_vertices[i];
+            out[i] = P * x; // vertex in xz plane
+        }
+#else // This code is not reliable because it shadow-projects a polygons which can skew computations
+        for (int i = 0; i < polygon_vertex_count; ++i) { // for each vertex
+            vec2& Tp = out[i];
+            int k = 0;
+            for (int j = 0; j < 3; j++) { // for each component
+                if (j != polygon_plane_normal_largest_component) { /* skip largest coordinate */
+
+                    Tp[k] = polygon_vertices[i][j];
+                    k++;
+                }
+            }
+        }
+#endif
+    }
+
+    // TODO: update this function to use "project_to_2d" for projection step
+    char compute_point_in_polygon_test(const vec3& p, const std::vector<vec3>& polygon_vertices,
+        const vec3& polygon_normal, const int polygon_normal_largest_component)
+    {
+        const int polygon_vertex_count = (int)polygon_vertices.size();
+        /* Project out coordinate m in both p and the triangular face */
+        vec2 pp; /*projected p */
+#if 0
+    int k = 0;
+    
+    for (int j = 0; j < 3; j++)
+    { // for each component
+        if (j != polygon_plane_normal_largest_component)
+        { /* skip largest coordinate */
+            pp[k] = p[j];
+            k++;
+        }
+    }
+#endif
+
+        const matrix_t<double> P = calculate_projection_matrix(polygon_normal, polygon_normal_largest_component);
+
+        pp = P * p;
+
+        std::vector<vec2> polygon_vertices2d(polygon_vertex_count, vec2());
+
+        for (int i = 0; i < polygon_vertex_count; ++i) { // for each vertex
+            const vec3& x = polygon_vertices[i];
+            polygon_vertices2d[i] = P * x; // vertex in xz plane
+        }
+
+#if 0
+    for (int i = 0; i < polygon_vertex_count; ++i)
+    { // for each vertex
+        vec2 &Tp = polygon_vertices2d[i];
+        k = 0;
+        for (int j = 0; j < 3; j++)
+        { // for each component
+            if (j != polygon_plane_normal_largest_component)
+            { /* skip largest coordinate */
+
+                Tp[k] = polygon_vertices[i][j];
+                k++;
+            }
+        }
+    }
+#endif
+
+        return compute_point_in_polygon_test(pp, polygon_vertices2d);
+    }
+
+    inline bool Between(const vec2& a, const vec2& b, const vec2& c)
+    {
+        vec2 ba, ca;
+        /* If ab not vertical check betweenness on x; else on y. */
+        if (a[0] != b[0])
+            return ((a[0] <= c[0]) && (c[0] <= b[0])) || //
+                ((a[0] >= c[0]) && (c[0] >= b[0]));
+        else
+            return ((a[1] <= c[1]) && (c[1] <= b[1])) || //
+                ((a[1] >= c[1]) && (c[1] >= b[1]));
+    }
+
+    bool coplaner(const vec3& pa, const vec3& pb, const vec3& pc,
+        const vec3& pd)
+    {
+        const double val = orient3d(pa, pb, pc, pd);
+        // typedef std::numeric_limits<double> dbl;
+
+        // double d = 3.14159265358979;
+        // std::cout.precision(dbl::max_digits10);
+        // std::cout << "value=" << (double)val << std::endl;
+
+        // NOTE: thresholds are chosen based on benchmark meshes that are used for testing.
+        // It is extremely difficult to get this right because of intermediate conversions
+        // between exact and fixed precision representations during cutting.
+        // Thus, general advise is for user to ensure that the input polygons are really
+        // co-planer. It might be possible for MCUT to help here (see eps used during poly
+        // partitioning).
+        return absolute_value(val) <= double(4e-7);
+    }
+
+    bool collinear(const vec2& a, const vec2& b, const vec2& c, double& predResult)
+    {
+        predResult = orient2d(a, b, c);
+        return predResult == double(0.);
+    }
+
+    bool collinear(const vec2& a, const vec2& b, const vec2& c)
+    {
+        return orient2d(a, b, c) == double(0.);
+    }
+
+    char Parallellnt(const vec2& a, const vec2& b, const vec2& c, const vec2& d, vec2& p)
+    {
+        if (!collinear(a, b, c)) {
+            return '0';
+        }
+
+        if (Between(a, b, c)) {
+            p = c;
+            return 'e';
+        }
+
+        if (Between(a, b, d)) {
+            p = d;
+            return 'e';
+        }
+
+        if (Between(c, d, a)) {
+            p = a;
+            return 'e';
+        }
+
+        if (Between(c, d, b)) {
+            p = b;
+            return 'e';
+        }
+
+        return '0';
+    }
+
+    char compute_segment_intersection(
+        const vec2& a, const vec2& b, const vec2& c, 
+        const vec2& d, vec2& p, double& s, double& t)
+    {
+        // double s, t; /* The two parameters of the parametric eqns. */
+        double num, denom; /* Numerator and denominator of equations. */
+        char code = '?'; /* Return char characterizing intersection.*/
+
+        denom = a[0] * (d[1] - c[1]) + //
+            b[0] * (c[1] - d[1]) + //
+            d[0] * (b[1] - a[1]) + //
+            c[0] * (a[1] - b[1]);
+
+        /* If denom is zero, then segments are parallel: handle separately. */
+        if (denom == double(0.0)) {
+            return Parallellnt(a, b, c, d, p);
+        }
+
+        num = a[0] * (d[1] - c[1]) + //
+            c[0] * (a[1] - d[1]) + //
+            d[0] * (c[1] - a[1]);
+
+        if ((num == double(0.0)) || (num == denom)) {
+            code = 'v';
+        }
+
+        s = num / denom;
+
+        num = -(a[0] * (c[1] - b[1]) + //
+            b[0] * (a[1] - c[1]) + //
+            c[0] * (b[1] - a[1]));
+
+        if ((num == double(0.0)) || (num == denom)) {
+            code = 'v';
+        }
+
+        t = num / denom;
+
+        if ((double(0.0) < s) && (s < double(1.0)) && (double(0.0) < t) && (t < double(1.0))) {
+            code = '1';
+        } else if ((double(0.0) > s) || (s > double(1.0)) || (double(0.0) > t) || (t > double(1.0))) {
+            code = '0';
+        }
+
+        p[0] = a[0] + s * (b[0] - a[0]);
+        p[1] = a[1] + s * (b[1] - a[1]);
+
+        return code;
+    }
+
+    inline bool point_in_bounding_box(const vec2& point, const bounding_box_t<vec2>& bbox)
+    {
+        if ((point.x() < bbox.m_minimum.x() || point.x() > bbox.m_maximum.x()) || //
+            (point.y() < bbox.m_minimum.y() || point.y() > bbox.m_maximum.y())) {
+            return false;
+        } else {
+            return true;
+        }
+    }
+
+    inline bool point_in_bounding_box(const vec3& point, const bounding_box_t<vec3>& bbox)
+    {
+        if ((point.x() < bbox.m_minimum.x() || point.x() > bbox.m_maximum.x()) || //
+            (point.y() < bbox.m_minimum.y() || point.y() > bbox.m_maximum.y()) || //
+            (point.z() < bbox.m_minimum.z() || point.z() > bbox.m_maximum.z())) { //
+            return false;
+        } else {
+            return true;
+        }
+    }
+
+

src/mcut/source/mcut.cpp

@@ -0,0 +1,892 @@
+/**
+ * Copyright (c) 2021-2022 Floyd M. Chitalu.
+ * All rights reserved.
+ *
+ * NOTE: This file is licensed under GPL-3.0-or-later (default).
+ * A commercial license can be purchased from Floyd M. Chitalu.
+ *
+ * License details:
+ *
+ * (A)  GNU General Public License ("GPL"); a copy of which you should have
+ *      recieved with this file.
+ * 	    - see also: <http://www.gnu.org/licenses/>
+ * (B)  Commercial license.
+ *      - email: floyd.m.chitalu@gmail.com
+ *
+ * The commercial license options is for users that wish to use MCUT in
+ * their products for comercial purposes but do not wish to release their
+ * software products under the GPL license.
+ *
+ * Author(s)     : Floyd M. Chitalu
+ */
+
+#include "mcut/mcut.h"
+
+#include "mcut/internal/frontend.h"
+#include "mcut/internal/timer.h"
+#include "mcut/internal/utils.h"
+
+#include <exception>
+#include <stdexcept>
+
+#if defined(MCUT_BUILD_WINDOWS)
+#pragma warning(disable : 26812)
+#endif
+
+MCAPI_ATTR McResult MCAPI_CALL mcCreateContext(McContext* pOutContext, McFlags contextFlags)
+{
+    McResult return_value = McResult::MC_NO_ERROR;
+    per_thread_api_log_str.clear();
+
+    if (pOutContext == nullptr) {
+        per_thread_api_log_str = "context ptr undef (NULL)";
+        return_value = McResult::MC_INVALID_VALUE;
+    } else {
+        try {
+            // no helper threads
+            // only manager threads (2 managers if context is created with MC_OUT_OF_ORDER_EXEC_MODE_ENABLE, otherwise 1 manager)
+            create_context_impl(pOutContext, contextFlags, 0);
+        }
+        CATCH_POSSIBLE_EXCEPTIONS(per_thread_api_log_str);
+    }
+
+    if (return_value != McResult::MC_NO_ERROR) {
+        std::fprintf(stderr, "%s(...) -> %s\n", __FUNCTION__, per_thread_api_log_str.c_str());
+    }
+
+    return return_value;
+}
+
+MCAPI_ATTR McResult MCAPI_CALL mcCreateContextWithHelpers(McContext* pOutContext, McFlags contextFlags, uint32_t helperThreadCount)
+{
+    McResult return_value = McResult::MC_NO_ERROR;
+    per_thread_api_log_str.clear();
+
+    if (pOutContext == nullptr) {
+        per_thread_api_log_str = "context ptr undef (NULL)";
+        return_value = McResult::MC_INVALID_VALUE;
+    } else {
+        try {
+            create_context_impl(pOutContext, contextFlags, helperThreadCount);
+        }
+        CATCH_POSSIBLE_EXCEPTIONS(per_thread_api_log_str);
+    }
+
+    if (return_value != McResult::MC_NO_ERROR) {
+        std::fprintf(stderr, "%s(...) -> %s\n", __FUNCTION__, per_thread_api_log_str.c_str());
+    }
+
+    return return_value;
+}
+
+MCAPI_ATTR McResult MCAPI_CALL mcDebugMessageCallback(McContext pContext, pfn_mcDebugOutput_CALLBACK cb, const McVoid* userParam)
+{
+    McResult return_value = McResult::MC_NO_ERROR;
+    per_thread_api_log_str.clear();
+
+    if (pContext == nullptr) {
+        per_thread_api_log_str = "context ptr (param0) undef (NULL)";
+    } else if (cb == nullptr) {
+        per_thread_api_log_str = "callback function ptr (param1) undef (NULL)";
+    } else {
+        try {
+            debug_message_callback_impl(pContext, cb, userParam);
+        }
+        CATCH_POSSIBLE_EXCEPTIONS(per_thread_api_log_str);
+    }
+
+    if (!per_thread_api_log_str.empty()) {
+        std::fprintf(stderr, "%s(...) -> %s\n", __FUNCTION__, per_thread_api_log_str.c_str());
+
+        if (return_value == McResult::MC_NO_ERROR) // i.e. problem with basic local parameter checks
+        {
+            return_value = McResult::MC_INVALID_VALUE;
+        }
+    }
+
+    return return_value;
+}
+
+MCAPI_ATTR McResult MCAPI_CALL mcGetDebugMessageLog(
+    McContext context,
+    McUint32 count, McSize bufSize,
+    McDebugSource* sources, McDebugType* types, McDebugSeverity* severities,
+    McSize* lengths, McChar* messageLog, McUint32* numFetched)
+{
+    McResult return_value = McResult::MC_NO_ERROR;
+    per_thread_api_log_str.clear();
+
+    if (context == nullptr) {
+        per_thread_api_log_str = "context ptr (param0) undef (NULL)";
+    } else if (
+        count == 0) {
+        per_thread_api_log_str = "count must be > 0";
+    } else if (bufSize == 0) {
+        per_thread_api_log_str = "bufSize must be > 0";
+    } else if (numFetched == nullptr) {
+        per_thread_api_log_str = "numFetched  undef (NULL)";
+    } else {
+        try {
+            get_debug_message_log_impl(context,
+                count, bufSize,
+                sources, types, severities,
+                lengths, messageLog, *numFetched);
+        }
+        CATCH_POSSIBLE_EXCEPTIONS(per_thread_api_log_str);
+    }
+
+    if (!per_thread_api_log_str.empty()) {
+        std::fprintf(stderr, "%s(...) -> %s\n", __FUNCTION__, per_thread_api_log_str.c_str());
+        if (return_value == McResult::MC_NO_ERROR) // i.e. problem with basic local parameter checks
+        {
+            return_value = McResult::MC_INVALID_VALUE;
+        }
+    }
+
+    return return_value;
+}
+
+MCAPI_ATTR McResult MCAPI_CALL mcDebugMessageControl(McContext pContext, McDebugSource source, McDebugType type, McDebugSeverity severity, bool enabled)
+{
+    McResult return_value = McResult::MC_NO_ERROR;
+    per_thread_api_log_str.clear();
+
+    if (pContext == nullptr) {
+        per_thread_api_log_str = "context ptr (param0) undef (NULL)";
+    } else if (
+        false == (source == McDebugSource::MC_DEBUG_SOURCE_ALL || //
+            source == McDebugSource::MC_DEBUG_SOURCE_KERNEL || //
+            source == McDebugSource::MC_DEBUG_SOURCE_ALL)) {
+        per_thread_api_log_str = "debug source val (param1) invalid";
+    } else if (
+        false == (type == McDebugType::MC_DEBUG_TYPE_ALL || //
+            type == McDebugType::MC_DEBUG_TYPE_DEPRECATED_BEHAVIOR || //
+            type == McDebugType::MC_DEBUG_TYPE_ERROR || //
+            type == McDebugType::MC_DEBUG_TYPE_OTHER)) {
+        per_thread_api_log_str = "debug type val (param2) invalid";
+    } else if (
+        false == (severity == McDebugSeverity::MC_DEBUG_SEVERITY_HIGH || //
+            severity == McDebugSeverity::MC_DEBUG_SEVERITY_MEDIUM || //
+            severity == McDebugSeverity::MC_DEBUG_SEVERITY_LOW || //
+            severity == McDebugSeverity::MC_DEBUG_SEVERITY_NOTIFICATION || //
+            severity == McDebugSeverity::MC_DEBUG_SEVERITY_ALL)) {
+        per_thread_api_log_str = "debug severity val (param3) invalid";
+    } else {
+        try {
+            debug_message_control_impl(pContext, source, type, severity, enabled);
+        }
+        CATCH_POSSIBLE_EXCEPTIONS(per_thread_api_log_str);
+    }
+
+    if (!per_thread_api_log_str.empty()) {
+        std::fprintf(stderr, "%s(...) -> %s\n", __FUNCTION__, per_thread_api_log_str.c_str());
+        if (return_value == McResult::MC_NO_ERROR) // i.e. problem with basic local parameter checks
+        {
+            return_value = McResult::MC_INVALID_VALUE;
+        }
+    }
+
+    return return_value;
+}
+
+MCAPI_ATTR McResult MCAPI_CALL mcGetInfo(const McContext context, McFlags info, McSize bytes, McVoid* pMem, McSize* pNumBytes)
+{
+    McResult return_value = McResult::MC_NO_ERROR;
+    per_thread_api_log_str.clear();
+
+    if (context == nullptr) {
+        per_thread_api_log_str = "context ptr (param0) undef (NULL)";
+    } else if (bytes != 0 && pMem == nullptr) {
+        per_thread_api_log_str = "invalid specification (param2 & param3)";
+    } else if (false == //
+        (info == MC_CONTEXT_FLAGS || //
+            info == MC_CONTEXT_MAX_DEBUG_MESSAGE_LENGTH || //
+            info == MC_CONTEXT_GENERAL_POSITION_ENFORCEMENT_CONSTANT || //
+            info == MC_CONTEXT_GENERAL_POSITION_ENFORCEMENT_ATTEMPTS)) // check all possible values
+    {
+        per_thread_api_log_str = "invalid info flag val (param1)";
+    } else if ((info == MC_CONTEXT_FLAGS) && (pMem != nullptr && bytes != sizeof(McFlags))) {
+        per_thread_api_log_str = "invalid byte size (param2)"; // leads to e.g. "out of bounds" memory access during memcpy
+    } else {
+        try {
+            get_info_impl(context, info, bytes, pMem, pNumBytes);
+        }
+        CATCH_POSSIBLE_EXCEPTIONS(per_thread_api_log_str);
+    }
+
+    if (!per_thread_api_log_str.empty()) {
+        std::fprintf(stderr, "%s(...) -> %s\n", __FUNCTION__, per_thread_api_log_str.c_str());
+        if (return_value == McResult::MC_NO_ERROR) // i.e. problem with basic local parameter checks
+        {
+            return_value = McResult::MC_INVALID_VALUE;
+        }
+    }
+
+    return return_value;
+}
+
+MCAPI_ATTR McResult MCAPI_CALL mcBindState(
+    const McContext context,
+    McFlags stateInfo,
+    McSize bytes,
+    const McVoid* pMem)
+{
+    McResult return_value = McResult::MC_NO_ERROR;
+    per_thread_api_log_str.clear();
+
+    if (context == nullptr) {
+        per_thread_api_log_str = "context ptr (param0) undef (NULL)";
+    } else if (bytes == 0) {
+        per_thread_api_log_str = "invalid bytes ";
+    } else if (pMem == nullptr) {
+        per_thread_api_log_str = "invalid ptr (pMem)";
+    } else if (false == //
+        (stateInfo == MC_CONTEXT_GENERAL_POSITION_ENFORCEMENT_CONSTANT || //
+            stateInfo == MC_CONTEXT_GENERAL_POSITION_ENFORCEMENT_ATTEMPTS ||//
+            stateInfo == MC_CONTEXT_CONNECTED_COMPONENT_FACE_WINDING_ORDER)) // check all possible values
+    {
+        per_thread_api_log_str = "invalid stateInfo ";
+    } else if (
+        ((stateInfo == MC_CONTEXT_GENERAL_POSITION_ENFORCEMENT_CONSTANT) && bytes != sizeof(McDouble)) || //
+        ((stateInfo == MC_CONTEXT_GENERAL_POSITION_ENFORCEMENT_ATTEMPTS) && bytes != sizeof(McUint32))|| //
+        ((stateInfo == MC_CONTEXT_CONNECTED_COMPONENT_FACE_WINDING_ORDER) && bytes != sizeof(McConnectedComponentFaceWindingOrder))) {
+        per_thread_api_log_str = "invalid num bytes"; // leads to e.g. "out of bounds" memory access during memcpy
+    } else {
+        try {
+            bind_state_impl(context, stateInfo, bytes, pMem);
+        }
+        CATCH_POSSIBLE_EXCEPTIONS(per_thread_api_log_str);
+    }
+
+    if (!per_thread_api_log_str.empty()) {
+        std::fprintf(stderr, "%s(...) -> %s\n", __FUNCTION__, per_thread_api_log_str.c_str());
+        if (return_value == McResult::MC_NO_ERROR) // i.e. problem with basic local parameter checks
+        {
+            return_value = McResult::MC_INVALID_VALUE;
+        }
+    }
+
+    return return_value;
+}
+
+MCAPI_ATTR McResult MCAPI_CALL mcCreateUserEvent(
+    McEvent* event,
+    McContext context)
+{
+    McResult return_value = McResult::MC_NO_ERROR;
+    per_thread_api_log_str.clear();
+
+    if (event == nullptr) {
+        per_thread_api_log_str = "event ptr (param0) undef (NULL)";
+    } else if (context == nullptr) {
+        per_thread_api_log_str = "context handle undefined (NULL)";
+    } else {
+        try {
+            create_user_event_impl(event, context);
+        }
+        CATCH_POSSIBLE_EXCEPTIONS(per_thread_api_log_str);
+    }
+
+    if (!per_thread_api_log_str.empty()) {
+        std::fprintf(stderr, "%s(...) -> %s\n", __FUNCTION__, per_thread_api_log_str.c_str());
+        if (return_value == McResult::MC_NO_ERROR) // i.e. problem with basic local parameter checks
+        {
+            return_value = McResult::MC_INVALID_VALUE;
+        }
+    }
+
+    return return_value;
+}
+
+MCAPI_ATTR McResult MCAPI_CALL mcSetUserEventStatus(
+    McEvent event,
+    McInt32 execution_status)
+{
+    McResult return_value = McResult::MC_NO_ERROR;
+    per_thread_api_log_str.clear();
+
+    if (event == nullptr) {
+        per_thread_api_log_str = "event ptr (param0) undef (NULL)";
+    } else {
+        try {
+            set_user_event_status_impl(event, execution_status);
+        }
+        CATCH_POSSIBLE_EXCEPTIONS(per_thread_api_log_str);
+    }
+
+    if (!per_thread_api_log_str.empty()) {
+        std::fprintf(stderr, "%s(...) -> %s\n", __FUNCTION__, per_thread_api_log_str.c_str());
+        if (return_value == McResult::MC_NO_ERROR) // i.e. problem with basic local parameter checks
+        {
+            return_value = McResult::MC_INVALID_VALUE;
+        }
+    }
+
+    return return_value;
+}
+
+MCAPI_ATTR McResult MCAPI_CALL mcGetEventInfo(const McEvent event, McFlags info, McSize bytes, McVoid* pMem, McSize* pNumBytes)
+{
+    McResult return_value = McResult::MC_NO_ERROR;
+    per_thread_api_log_str.clear();
+
+    if (event == nullptr) {
+        per_thread_api_log_str = "context ptr (param0) undef (NULL)";
+    } else if (bytes != 0 && pMem == nullptr) {
+        per_thread_api_log_str = "invalid specification (param2 & param3)";
+    } else if ((info == MC_EVENT_RUNTIME_EXECUTION_STATUS) && (pMem != nullptr && bytes != sizeof(McResult))) {
+        per_thread_api_log_str = "invalid byte size (param2)"; // leads to e.g. "out of bounds" memory access during memcpy
+    } else if ((info == MC_EVENT_COMMAND_EXECUTION_STATUS) && (pMem != nullptr && bytes != sizeof(McFlags))) {
+        per_thread_api_log_str = "invalid byte size (param2)"; // leads to e.g. "out of bounds" memory access during memcpy
+    } else if ((info == MC_EVENT_TIMESTAMP_SUBMIT || info == MC_EVENT_TIMESTAMP_START || info == MC_EVENT_TIMESTAMP_END) && (pMem != nullptr && bytes != sizeof(McSize))) {
+        per_thread_api_log_str = "invalid byte size (param2)"; // leads to e.g. "out of bounds" memory access during memcpy
+    } else {
+        try {
+            get_event_info_impl(event, info, bytes, pMem, pNumBytes);
+        }
+        CATCH_POSSIBLE_EXCEPTIONS(per_thread_api_log_str);
+    }
+
+    if (!per_thread_api_log_str.empty()) {
+        std::fprintf(stderr, "%s(...) -> %s\n", __FUNCTION__, per_thread_api_log_str.c_str());
+        if (return_value == McResult::MC_NO_ERROR) // i.e. problem with basic local parameter checks
+        {
+            return_value = McResult::MC_INVALID_VALUE;
+        }
+    }
+
+    return return_value;
+}
+
+MCAPI_ATTR McResult MCAPI_CALL mcWaitForEvents(
+    uint32_t numEventsInWaitlist,
+    const McEvent* pEventWaitList)
+{
+    McResult return_value = McResult::MC_NO_ERROR;
+    per_thread_api_log_str.clear();
+
+    if (pEventWaitList == nullptr && numEventsInWaitlist > 0) {
+        per_thread_api_log_str = "invalid event waitlist ptr (NULL)";
+    } else if (pEventWaitList != nullptr && numEventsInWaitlist == 0) {
+        per_thread_api_log_str = "invalid event waitlist size (zero)";
+    } else {
+        try {
+            McResult waitliststatus = MC_NO_ERROR;
+            wait_for_events_impl(numEventsInWaitlist, pEventWaitList, waitliststatus);
+
+            if (waitliststatus != McResult::MC_NO_ERROR) {
+                per_thread_api_log_str = "event in waitlist has an error";
+            }
+        }
+        CATCH_POSSIBLE_EXCEPTIONS(per_thread_api_log_str);
+    }
+
+    if (!per_thread_api_log_str.empty()) {
+
+        std::fprintf(stderr, "%s(...) -> %s\n", __FUNCTION__, per_thread_api_log_str.c_str());
+
+        if (return_value == McResult::MC_NO_ERROR) // i.e. problem with basic local parameter checks
+        {
+            return_value = McResult::MC_INVALID_VALUE;
+        }
+    }
+
+    return return_value;
+}
+
+MCAPI_ATTR McResult MCAPI_CALL mcSetEventCallback(
+    McEvent eventHandle,
+    pfn_McEvent_CALLBACK eventCallback,
+    McVoid* data)
+{
+    McResult return_value = McResult::MC_NO_ERROR;
+    per_thread_api_log_str.clear();
+
+    if (eventHandle == nullptr) {
+        per_thread_api_log_str = "invalid event ptr (NULL)";
+    }
+    if (eventCallback == nullptr) {
+        per_thread_api_log_str = "invalid event callback function ptr (NULL)";
+    } else {
+        try {
+            set_event_callback_impl(eventHandle, eventCallback, data);
+        }
+        CATCH_POSSIBLE_EXCEPTIONS(per_thread_api_log_str);
+    }
+
+    if (!per_thread_api_log_str.empty()) {
+
+        std::fprintf(stderr, "%s(...) -> %s\n", __FUNCTION__, per_thread_api_log_str.c_str());
+
+        if (return_value == McResult::MC_NO_ERROR) // i.e. problem with basic local parameter checks
+        {
+            return_value = McResult::MC_INVALID_VALUE;
+        }
+    }
+
+    return return_value;
+}
+
+MCAPI_ATTR McResult MCAPI_CALL mcEnqueueDispatch(
+    const McContext context,
+    McFlags dispatchFlags,
+    const McVoid* pSrcMeshVertices,
+    const uint32_t* pSrcMeshFaceIndices,
+    const uint32_t* pSrcMeshFaceSizes,
+    uint32_t numSrcMeshVertices,
+    uint32_t numSrcMeshFaces,
+    const McVoid* pCutMeshVertices,
+    const uint32_t* pCutMeshFaceIndices,
+    const uint32_t* pCutMeshFaceSizes,
+    uint32_t numCutMeshVertices,
+    uint32_t numCutMeshFaces,
+    uint32_t numEventsInWaitlist,
+    const McEvent* pEventWaitList,
+    McEvent* pEvent)
+{
+   
+    McResult return_value = McResult::MC_NO_ERROR;
+    per_thread_api_log_str.clear();
+
+    if (context == nullptr) {
+        per_thread_api_log_str = "context ptr (param0) undef (NULL)";
+    } else if (dispatchFlags == 0) {
+        per_thread_api_log_str = "dispatch flags unspecified";
+    } else if ((dispatchFlags & MC_DISPATCH_REQUIRE_THROUGH_CUTS) && //
+        (dispatchFlags & MC_DISPATCH_FILTER_FRAGMENT_LOCATION_UNDEFINED)) {
+        // The user states that she does not want a partial cut but yet also states that she
+        // wants to keep fragments with partial cuts. These two options are mutually exclusive!
+        per_thread_api_log_str = "use of mutually-exclusive flags: MC_DISPATCH_REQUIRE_THROUGH_CUTS & MC_DISPATCH_FILTER_FRAGMENT_LOCATION_UNDEFINED";
+    } else if ((dispatchFlags & MC_DISPATCH_VERTEX_ARRAY_FLOAT) == 0 && (dispatchFlags & MC_DISPATCH_VERTEX_ARRAY_DOUBLE) == 0) {
+        per_thread_api_log_str = "dispatch vertex aray type unspecified";
+    } else if (pSrcMeshVertices == nullptr) {
+        per_thread_api_log_str = "source-mesh vertex-position array ptr undef (NULL)";
+    } else if (numSrcMeshVertices < 3) {
+        per_thread_api_log_str = "invalid source-mesh vertex count";
+    } else if (pSrcMeshFaceIndices == nullptr) {
+        per_thread_api_log_str = "source-mesh face-index array ptr undef (NULL)";
+    } /*else if (pSrcMeshFaceSizes == nullptr) {
+        per_thread_api_log_str = "source-mesh face-size array ptr undef (NULL)";
+    }*/
+    else if (numSrcMeshFaces < 1) {
+        per_thread_api_log_str = "invalid source-mesh vertex count";
+    } else if (pCutMeshVertices == nullptr) {
+        per_thread_api_log_str = "cut-mesh vertex-position array ptr undef (NULL)";
+    } else if (numCutMeshVertices < 3) {
+        per_thread_api_log_str = "invalid cut-mesh vertex count";
+    } else if (pCutMeshFaceIndices == nullptr) {
+        per_thread_api_log_str = "cut-mesh face-index array ptr undef (NULL)";
+    } /*else if (pCutMeshFaceSizes == nullptr) {
+        per_thread_api_log_str = "cut-mesh face-size array ptr undef (NULL)";
+    } */
+    else if (numCutMeshFaces < 1) {
+        per_thread_api_log_str = "invalid cut-mesh vertex count";
+    } else if (pEventWaitList == nullptr && numEventsInWaitlist > 0) {
+        per_thread_api_log_str = "invalid event waitlist ptr (NULL)";
+    } else if (pEventWaitList != nullptr && numEventsInWaitlist == 0) {
+        per_thread_api_log_str = "invalid event waitlist size (zero)";
+    } else if (pEventWaitList == nullptr && numEventsInWaitlist == 0 && pEvent == nullptr) {
+        per_thread_api_log_str = "invalid event ptr (zero)";
+    } else {
+        try {
+            dispatch_impl(
+                context,
+                dispatchFlags,
+                pSrcMeshVertices,
+                pSrcMeshFaceIndices,
+                pSrcMeshFaceSizes,
+                numSrcMeshVertices,
+                numSrcMeshFaces,
+                pCutMeshVertices,
+                pCutMeshFaceIndices,
+                pCutMeshFaceSizes,
+                numCutMeshVertices,
+                numCutMeshFaces,
+                numEventsInWaitlist,
+                pEventWaitList,
+                pEvent);
+        }
+        CATCH_POSSIBLE_EXCEPTIONS(per_thread_api_log_str);
+    }
+
+    if (!per_thread_api_log_str.empty()) {
+
+        std::fprintf(stderr, "%s(...) -> %s\n", __FUNCTION__, per_thread_api_log_str.c_str());
+
+        if (return_value == McResult::MC_NO_ERROR) // i.e. problem with basic local parameter checks
+        {
+            return_value = McResult::MC_INVALID_VALUE;
+        }
+    }
+
+    return return_value;
+}
+
+MCAPI_ATTR McResult MCAPI_CALL mcDispatch(
+    const McContext context,
+    McFlags dispatchFlags,
+    const McVoid* pSrcMeshVertices,
+    const uint32_t* pSrcMeshFaceIndices,
+    const uint32_t* pSrcMeshFaceSizes,
+    uint32_t numSrcMeshVertices,
+    uint32_t numSrcMeshFaces,
+    const McVoid* pCutMeshVertices,
+    const uint32_t* pCutMeshFaceIndices,
+    const uint32_t* pCutMeshFaceSizes,
+    uint32_t numCutMeshVertices,
+    uint32_t numCutMeshFaces)
+{
+    McEvent event = MC_NULL_HANDLE;
+
+    McResult return_value = mcEnqueueDispatch(
+        context,
+        dispatchFlags,
+        pSrcMeshVertices,
+        pSrcMeshFaceIndices,
+        pSrcMeshFaceSizes,
+        numSrcMeshVertices,
+        numSrcMeshFaces,
+        pCutMeshVertices,
+        pCutMeshFaceIndices,
+        pCutMeshFaceSizes,
+        numCutMeshVertices,
+        numCutMeshFaces,
+        0,
+        nullptr,
+        &event);
+
+    if (return_value == MC_NO_ERROR) { // API parameter checks are fine
+        if (event != MC_NULL_HANDLE) // event must exist to wait on and query
+        {
+            McResult waitliststatus = MC_NO_ERROR;
+
+            wait_for_events_impl(1, &event, waitliststatus); // block until event of mcEnqueueDispatch is completed!
+
+            if (waitliststatus != McResult::MC_NO_ERROR) {
+                return_value = waitliststatus;
+            }
+
+            release_events_impl(1, &event); // destroy
+        }
+    }
+
+    return return_value;
+}
+
+MCAPI_ATTR McResult MCAPI_CALL mcEnqueueDispatchPlanarSection(
+    const McContext context,
+    McFlags dispatchFlags,
+    const McVoid* pSrcMeshVertices,
+    const uint32_t* pSrcMeshFaceIndices,
+    const uint32_t* pSrcMeshFaceSizes,
+    uint32_t numSrcMeshVertices,
+    uint32_t numSrcMeshFaces,
+    const McDouble* pNormalVector,
+    const McDouble sectionOffset,
+    uint32_t numEventsInWaitlist,
+    const McEvent* pEventWaitList,
+    McEvent* pEvent)
+    {
+        McResult return_value = McResult::MC_NO_ERROR;
+    per_thread_api_log_str.clear();
+
+    if (context == nullptr) {
+        per_thread_api_log_str = "context ptr (param0) undef (NULL)";
+    } else if (dispatchFlags == 0) {
+        per_thread_api_log_str = "dispatch flags unspecified";
+    } else if ((dispatchFlags & MC_DISPATCH_REQUIRE_THROUGH_CUTS) && //
+        (dispatchFlags & MC_DISPATCH_FILTER_FRAGMENT_LOCATION_UNDEFINED)) {
+        // The user states that she does not want a partial cut but yet also states that she
+        // wants to keep fragments with partial cuts. These two options are mutually exclusive!
+        per_thread_api_log_str = "use of mutually-exclusive flags: MC_DISPATCH_REQUIRE_THROUGH_CUTS & MC_DISPATCH_FILTER_FRAGMENT_LOCATION_UNDEFINED";
+    } else if ((dispatchFlags & MC_DISPATCH_VERTEX_ARRAY_FLOAT) == 0 && (dispatchFlags & MC_DISPATCH_VERTEX_ARRAY_DOUBLE) == 0) {
+        per_thread_api_log_str = "dispatch vertex aray type unspecified";
+    } else if (pSrcMeshVertices == nullptr) {
+        per_thread_api_log_str = "source-mesh vertex-position array ptr undef (NULL)";
+    } else if (numSrcMeshVertices < 3) {
+        per_thread_api_log_str = "invalid source-mesh vertex count";
+    } else if (pSrcMeshFaceIndices == nullptr) {
+        per_thread_api_log_str = "source-mesh face-index array ptr undef (NULL)";
+    } /*else if (pSrcMeshFaceSizes == nullptr) {
+        per_thread_api_log_str = "source-mesh face-size array ptr undef (NULL)";
+    }*/
+    else if (numSrcMeshFaces < 1) {
+        per_thread_api_log_str = "invalid source-mesh vertex count";
+    } else if (pNormalVector == nullptr) {
+        per_thread_api_log_str = "normal vector ptr undef (NULL)";
+    } else if (pNormalVector[0] == 0.0 && pNormalVector[1] == 0.0 && pNormalVector[2] == 0.0) {
+        per_thread_api_log_str = "invalid normal vector (zero vector)";
+    }else if (sectionOffset <= 0 && sectionOffset >= 1.0) {
+        per_thread_api_log_str = "invalid section offset parameter";
+    } else if (pEventWaitList == nullptr && numEventsInWaitlist > 0) {
+        per_thread_api_log_str = "invalid event waitlist ptr (NULL)";
+    } else if (pEventWaitList != nullptr && numEventsInWaitlist == 0) {
+        per_thread_api_log_str = "invalid event waitlist size (zero)";
+    } else if (pEventWaitList == nullptr && numEventsInWaitlist == 0 && pEvent == nullptr) {
+        per_thread_api_log_str = "invalid event ptr (zero)";
+    } else {
+        try {
+            dispatch_planar_section_impl(
+                context,
+                dispatchFlags,
+                pSrcMeshVertices,
+                pSrcMeshFaceIndices,
+                pSrcMeshFaceSizes,
+                numSrcMeshVertices,
+                numSrcMeshFaces,
+                pNormalVector,
+                sectionOffset,
+                numEventsInWaitlist,
+                pEventWaitList,
+                pEvent);
+        }
+        CATCH_POSSIBLE_EXCEPTIONS(per_thread_api_log_str);
+    }
+
+    if (!per_thread_api_log_str.empty()) {
+
+        std::fprintf(stderr, "%s(...) -> %s\n", __FUNCTION__, per_thread_api_log_str.c_str());
+
+        if (return_value == McResult::MC_NO_ERROR) // i.e. problem with basic local parameter checks
+        {
+            return_value = McResult::MC_INVALID_VALUE;
+        }
+    }
+
+    return return_value;
+    }
+
+MCAPI_ATTR McResult MCAPI_CALL mcEnqueueGetConnectedComponents(
+    const McContext context,
+    const McConnectedComponentType connectedComponentType,
+    const uint32_t numEntries,
+    McConnectedComponent* pConnComps,
+    uint32_t* numConnComps,
+    uint32_t numEventsInWaitlist,
+    const McEvent* pEventWaitList,
+    McEvent* pEvent)
+{
+    McResult return_value = McResult::MC_NO_ERROR;
+    per_thread_api_log_str.clear();
+
+    if (context == nullptr) {
+        per_thread_api_log_str = "context ptr (param0) undef (NULL)";
+    } else if (connectedComponentType == 0) {
+        per_thread_api_log_str = "invalid type-parameter (param1) (0)";
+    } else if (numConnComps == nullptr && pConnComps == nullptr) {
+        per_thread_api_log_str = "output parameters undef (param3 & param4)";
+    } else if (pEventWaitList == nullptr && numEventsInWaitlist > 0) {
+        per_thread_api_log_str = "invalid event waitlist ptr (NULL)";
+    } else if (pEventWaitList != nullptr && numEventsInWaitlist == 0) {
+        per_thread_api_log_str = "invalid event waitlist size (zero)";
+    } else if (pEventWaitList == nullptr && numEventsInWaitlist == 0 && pEvent == nullptr) {
+        per_thread_api_log_str = "invalid event ptr (zero)";
+    } else {
+        try {
+
+            get_connected_components_impl(context, connectedComponentType, numEntries, pConnComps, numConnComps, numEventsInWaitlist, pEventWaitList, pEvent);
+        }
+        CATCH_POSSIBLE_EXCEPTIONS(per_thread_api_log_str);
+    }
+
+    if (!per_thread_api_log_str.empty()) {
+
+        std::fprintf(stderr, "%s(...) -> %s\n", __FUNCTION__, per_thread_api_log_str.c_str());
+
+        if (return_value == McResult::MC_NO_ERROR) // i.e. problem with basic local parameter checks
+        {
+            return_value = McResult::MC_INVALID_VALUE;
+        }
+    }
+
+    return return_value;
+}
+
+MCAPI_ATTR McResult MCAPI_CALL mcGetConnectedComponents(
+    const McContext context,
+    const McConnectedComponentType connectedComponentType,
+    const uint32_t numEntries,
+    McConnectedComponent* pConnComps,
+    uint32_t* numConnComps)
+{
+    McEvent event = MC_NULL_HANDLE;
+    McResult return_value = mcEnqueueGetConnectedComponents(context, connectedComponentType, numEntries, pConnComps, numConnComps, 0, nullptr, &event);
+    if (event != MC_NULL_HANDLE) // event must exist to wait on and query
+    {
+        McResult waitliststatus = MC_NO_ERROR;
+
+        wait_for_events_impl(1, &event, waitliststatus); // block until event of mcEnqueueDispatch is completed!
+
+        if (waitliststatus != McResult::MC_NO_ERROR) {
+            return_value = waitliststatus;
+        }
+        release_events_impl(1, &event); // destroy
+    }
+    return return_value;
+}
+
+MCAPI_ATTR McResult MCAPI_CALL mcEnqueueGetConnectedComponentData(
+    const McContext context,
+    const McConnectedComponent connCompId,
+    McFlags queryFlags,
+    McSize bytes,
+    McVoid* pMem,
+    McSize* pNumBytes,
+    uint32_t numEventsInWaitlist,
+    const McEvent* pEventWaitList,
+    McEvent* pEvent)
+{
+    McResult return_value = McResult::MC_NO_ERROR;
+    per_thread_api_log_str.clear();
+
+    if (context == nullptr) {
+        per_thread_api_log_str = "context ptr (param0) undef (NULL)";
+    }
+    if (connCompId == nullptr) {
+        per_thread_api_log_str = "connected component ptr (param1) undef (NULL)";
+    } else if (queryFlags == 0) {
+        per_thread_api_log_str = "flags (param1) undef (0)";
+    } else if (bytes != 0 && pMem == nullptr) {
+        per_thread_api_log_str = "null parameter (param3 & param4)";
+    } else if (pEventWaitList == nullptr && numEventsInWaitlist > 0) {
+        per_thread_api_log_str = "invalid event waitlist ptr (NULL)";
+    } else if (pEventWaitList != nullptr && numEventsInWaitlist == 0) {
+        per_thread_api_log_str = "invalid event waitlist size (zero)";
+    } else if (pEventWaitList == nullptr && numEventsInWaitlist == 0 && pEvent == nullptr) {
+        per_thread_api_log_str = "invalid event ptr (zero)";
+    } else {
+        try {
+            get_connected_component_data_impl(context, connCompId, queryFlags, bytes, pMem, pNumBytes, numEventsInWaitlist, pEventWaitList, pEvent);
+        }
+        CATCH_POSSIBLE_EXCEPTIONS(per_thread_api_log_str);
+    }
+
+    if (!per_thread_api_log_str.empty()) {
+
+        std::fprintf(stderr, "%s(...) -> %s\n", __FUNCTION__, per_thread_api_log_str.c_str());
+
+        if (return_value == McResult::MC_NO_ERROR) // i.e. problem with basic local parameter checks
+        {
+            return_value = McResult::MC_INVALID_VALUE;
+        }
+    }
+
+    return return_value;
+}
+
+MCAPI_ATTR McResult MCAPI_CALL mcGetConnectedComponentData(
+    const McContext context,
+    const McConnectedComponent connCompId,
+    McFlags queryFlags,
+    McSize bytes,
+    McVoid* pMem,
+    McSize* pNumBytes)
+{
+    McEvent event = MC_NULL_HANDLE;
+    McResult return_value = mcEnqueueGetConnectedComponentData(context, connCompId, queryFlags, bytes, pMem, pNumBytes, 0, nullptr, &event);
+    if (event != MC_NULL_HANDLE) // event must exist to wait on and query
+    {
+        McResult waitliststatus = MC_NO_ERROR;
+
+        wait_for_events_impl(1, &event, waitliststatus); // block until event of mcEnqueueDispatch is completed!
+
+        if (waitliststatus != McResult::MC_NO_ERROR) {
+            return_value = waitliststatus;
+        }
+
+        release_events_impl(1, &event); // destroy
+    }
+    return return_value;
+}
+
+MCAPI_ATTR McResult MCAPI_CALL mcReleaseEvents(
+    uint32_t numEvents,
+    const McEvent* pEvents)
+{
+    McResult return_value = McResult::MC_NO_ERROR;
+    per_thread_api_log_str.clear();
+
+    if (numEvents > 0 && pEvents == NULL) {
+        per_thread_api_log_str = "invalid pointer to events";
+    } else if (numEvents == 0 && pEvents != NULL) {
+        per_thread_api_log_str = "number of events not set";
+    } else {
+        try {
+            release_events_impl(numEvents, pEvents);
+        }
+        CATCH_POSSIBLE_EXCEPTIONS(per_thread_api_log_str);
+    }
+
+    if (!per_thread_api_log_str.empty()) {
+
+        std::fprintf(stderr, "%s(...) -> %s\n", __FUNCTION__, per_thread_api_log_str.c_str());
+
+        if (return_value == McResult::MC_NO_ERROR) // i.e. problem with basic local parameter checks
+        {
+            return_value = McResult::MC_INVALID_VALUE;
+        }
+    }
+
+    return return_value;
+}
+
+MCAPI_ATTR McResult MCAPI_CALL mcReleaseConnectedComponents(
+    const McContext context,
+    uint32_t numConnComps,
+    const McConnectedComponent* pConnComps)
+{
+    McResult return_value = McResult::MC_NO_ERROR;
+    per_thread_api_log_str.clear();
+
+    if (context == nullptr) {
+        per_thread_api_log_str = "context ptr (param0) undef (NULL)";
+    } else if (numConnComps > 0 && pConnComps == NULL) {
+        per_thread_api_log_str = "invalid pointer to connected components";
+    } else if (numConnComps == 0 && pConnComps != NULL) {
+        per_thread_api_log_str = "number of connected components not set";
+    } else {
+        try {
+            release_connected_components_impl(context, numConnComps, pConnComps);
+        }
+        CATCH_POSSIBLE_EXCEPTIONS(per_thread_api_log_str);
+    }
+
+    if (!per_thread_api_log_str.empty()) {
+
+        std::fprintf(stderr, "%s(...) -> %s\n", __FUNCTION__, per_thread_api_log_str.c_str());
+
+        if (return_value == McResult::MC_NO_ERROR) // i.e. problem with basic local parameter checks
+        {
+            return_value = McResult::MC_INVALID_VALUE;
+        }
+    }
+
+    return return_value;
+}
+
+MCAPI_ATTR McResult MCAPI_CALL mcReleaseContext(const McContext context)
+{
+    McResult return_value = McResult::MC_NO_ERROR;
+    per_thread_api_log_str.clear();
+
+    if (context == nullptr) {
+        per_thread_api_log_str = "context ptr (param0) undef (NULL)";
+    } else {
+        try {
+            release_context_impl(context);
+        }
+        CATCH_POSSIBLE_EXCEPTIONS(per_thread_api_log_str);
+    }
+
+    if (!per_thread_api_log_str.empty()) {
+
+        std::fprintf(stderr, "%s(...) -> %s\n", __FUNCTION__, per_thread_api_log_str.c_str());
+
+        if (return_value == McResult::MC_NO_ERROR) // i.e. problem with basic local parameter checks
+        {
+            return_value = McResult::MC_INVALID_VALUE;
+        }
+    }
+
+    return return_value;
+}

src/slic3r/CMakeLists.txt

@@ -546,3 +546,6 @@ if (UNIX AND NOT APPLE)
     target_link_libraries(libslic3r_gui ${GSTREAMER_LIBRARIES} ${GST_BASE_LIBRARIES})
     target_include_directories(libslic3r_gui PRIVATE ${GSTREAMER_INCLUDE_DIRS} ${GST_BASE_INCLUDE_DIRS})
 endif ()
+
+# Add a definition so that we can tell we are compiling slic3r.
+target_compile_definitions(libslic3r_gui PRIVATE SLIC3R_CURRENTLY_COMPILING_GUI_MODULE)

src/slic3r/GUI/ConfigManipulation.cpp

@@ -559,7 +559,7 @@ void ConfigManipulation::toggle_print_fff_options(DynamicPrintConfig *config, co
     bool has_bottom_solid_infill = config->opt_int("bottom_shell_layers") > 0;
     bool has_solid_infill 		 = has_top_solid_infill || has_bottom_solid_infill;
     // solid_infill_filament uses the same logic as in Print::extruders()
-    for (auto el : { "top_surface_pattern", "bottom_surface_pattern", "solid_infill_filament"})
+    for (auto el : { "top_surface_pattern", "bottom_surface_pattern", "internal_solid_infill_pattern", "solid_infill_filament"})
         toggle_field(el, has_solid_infill);
 
     for (auto el : { "infill_direction", "sparse_infill_line_width",

src/slic3r/GUI/Field.cpp

@@ -1295,7 +1295,7 @@ void Choice::set_value(const boost::any& value, bool change_event)
         if (m_opt_id.compare("host_type") == 0 && val != 0 &&
 			m_opt.enum_values.size() > field->GetCount()) // for case, when PrusaLink isn't used as a HostType
 			val--;
-        if (m_opt_id == "top_surface_pattern" || m_opt_id == "bottom_surface_pattern" || m_opt_id == "sparse_infill_pattern" || m_opt_id == "support_style")
+        if (m_opt_id == "top_surface_pattern" || m_opt_id == "bottom_surface_pattern" || m_opt_id == "internal_solid_infill_pattern" || m_opt_id == "sparse_infill_pattern" || m_opt_id == "support_style")
 		{
 			std::string key;
 			const t_config_enum_values& map_names = *m_opt.enum_keys_map;
@@ -1382,7 +1382,7 @@ boost::any& Choice::get_value()
 	{
         if (m_opt.nullable && field->GetSelection() == -1)
             m_value = ConfigOptionEnumsGenericNullable::nil_value();
-        else if (m_opt_id == "top_surface_pattern" || m_opt_id == "bottom_surface_pattern" || m_opt_id == "sparse_infill_pattern" || m_opt_id == "support_style") {
+        else if (m_opt_id == "top_surface_pattern" || m_opt_id == "bottom_surface_pattern" || m_opt_id == "internal_solid_infill_pattern" || m_opt_id == "sparse_infill_pattern" || m_opt_id == "support_style") {
 			const std::string& key = m_opt.enum_values[field->GetSelection()];
 			m_value = int(m_opt.enum_keys_map->at(key));
 		}

src/slic3r/GUI/GUI.cpp

@@ -285,6 +285,7 @@ static void add_config_substitutions(const ConfigSubstitutions& conf_substitutio
 
 			bool is_infill = def->opt_key == "top_surface_pattern"	   ||
 							 def->opt_key == "bottom_surface_pattern" ||
+							 def->opt_key == "internal_solid_infill_pattern" ||
 							 def->opt_key == "sparse_infill_pattern";
 
 			// Each infill doesn't use all list of infill declared in PrintConfig.hpp.

src/slic3r/GUI/GUI_Factories.cpp

@@ -96,7 +96,7 @@ std::map<std::string, std::vector<SimpleSettingData>>  SettingsFactory::PART_CAT
                     }},
     { L("Strength"), {{"wall_loops", "",1},{"top_shell_layers", L("Top Solid Layers"),1},{"top_shell_thickness", L("Top Minimum Shell Thickness"),1},
                     {"bottom_shell_layers", L("Bottom Solid Layers"),1}, {"bottom_shell_thickness", L("Bottom Minimum Shell Thickness"),1},
-                    {"sparse_infill_density", "",1},{"sparse_infill_pattern", "",1},{"infill_anchor", "",1},{"infill_anchor_max", "",1},{"top_surface_pattern", "",1},{"bottom_surface_pattern", "",1},
+                    {"sparse_infill_density", "",1},{"sparse_infill_pattern", "",1},{"infill_anchor", "",1},{"infill_anchor_max", "",1},{"top_surface_pattern", "",1},{"bottom_surface_pattern", "",1}, {"internal_solid_infill_pattern", "",1},
                     {"infill_combination", "",1}, {"infill_wall_overlap", "",1}, {"infill_direction", "",1}, {"bridge_angle", "",1}, {"minimum_sparse_infill_area", "",1}
                     }},
     { L("Speed"), {{"outer_wall_speed", "",1},{"inner_wall_speed", "",2},{"sparse_infill_speed", "",3},{"top_surface_speed", "",4}, {"internal_solid_infill_speed", "",5},

src/slic3r/GUI/Tab.cpp

@@ -1906,6 +1906,7 @@ void TabPrint::build()
         optgroup->append_single_option_line("bottom_surface_pattern", "fill-patterns#Infill of the top surface and bottom surface");
         optgroup->append_single_option_line("bottom_shell_layers");
         optgroup->append_single_option_line("bottom_shell_thickness");
+        optgroup->append_single_option_line("internal_solid_infill_pattern");
 
         optgroup = page->new_optgroup(L("Infill"), L"param_infill");
         optgroup->append_single_option_line("sparse_infill_density");
@@ -2677,7 +2678,7 @@ void TabFilament::build()
         optgroup = page->new_optgroup(L("Print temperature"), L"param_temperature");
         optgroup->split_multi_line = true;
         optgroup->option_label_at_right = true;
-        optgroup->append_single_option_line("chamber_temperatures");
+        optgroup->append_single_option_line("chamber_temperature");
 
 
         line = { L("Nozzle"), L("Nozzle temperature when printing") };
@@ -2896,7 +2897,7 @@ void TabFilament::toggle_options()
         toggle_line("cool_plate_temp_initial_layer", is_BBL_printer);
         toggle_line("eng_plate_temp_initial_layer", is_BBL_printer);
         toggle_line("textured_plate_temp_initial_layer", is_BBL_printer);
-        toggle_option("chamber_temperatures", !is_BBL_printer);
+        toggle_option("chamber_temperature", !is_BBL_printer);
     }
     if (m_active_page->title() == "Setting Overrides")
         update_filament_overrides_page();

src/slic3r/GUI/UnsavedChangesDialog.cpp

@@ -1338,12 +1338,14 @@ static wxString get_string_value(std::string opt_key, const DynamicPrintConfig&
         return get_string_from_enum(opt_key, config,
             opt_key == "top_surface_pattern" ||
             opt_key == "bottom_surface_pattern" ||
+            opt_key == "internal_solid_infill_pattern" ||
             opt_key == "sparse_infill_pattern");
     }
     case coEnums: {
         return get_string_from_enum(opt_key, config,
             opt_key == "top_surface_pattern" ||
             opt_key == "bottom_surface_pattern" ||
+            opt_key == "internal_solid_infill_pattern" ||
             opt_key == "sparse_infill_pattern",
             opt_idx);
     }