New feature: Splitting an object into a multi-part volume.

xs/src/libslic3r/Model.cpp

@@ -685,6 +685,36 @@ ModelMaterial* ModelVolume::assign_unique_material()
     return model->add_material(this->_material_id);
 }
 
+// Split this volume, append the result to the object owning this volume.
+// Return the number of volumes created from this one.
+// This is useful to assign different materials to different volumes of an object.
+size_t ModelVolume::split()
+{
+    TriangleMeshPtrs meshptrs = this->mesh.split();
+    if (meshptrs.size() <= 1) {
+        delete meshptrs.front();
+        return 1;
+    }
+
+    size_t idx = 0;
+    size_t ivolume = std::find(this->object->volumes.begin(), this->object->volumes.end(), this) - this->object->volumes.begin();
+    std::string name = this->name;
+    for (TriangleMesh *mesh : meshptrs) {
+        mesh->repair();
+        if (idx == 0)
+            this->mesh = std::move(*mesh);
+        else
+            this->object->volumes.insert(this->object->volumes.begin() + (++ ivolume), new ModelVolume(object, *this, std::move(*mesh)));
+        char str_idx[64];
+        sprintf(str_idx, "_%d", idx + 1);
+        this->object->volumes[ivolume]->name = name + str_idx;
+        delete mesh;
+        ++ idx;
+    }
+    
+    return idx;
+}
+
 void ModelInstance::transform_mesh(TriangleMesh* mesh, bool dont_translate) const
 {
     mesh->rotate_z(this->rotation);                 // rotate around mesh origin

xs/src/libslic3r/Model.hpp

@@ -161,6 +161,10 @@ public:
     void material_id(t_model_material_id material_id);
     ModelMaterial* material() const;
     void set_material(t_model_material_id material_id, const ModelMaterial &material);
+    // Split this volume, append the result to the object owning this volume.
+    // Return the number of volumes created from this one.
+    // This is useful to assign different materials to different volumes of an object.
+    size_t split();
     
     ModelMaterial* assign_unique_material();
     
@@ -174,6 +178,9 @@ private:
     ModelVolume(ModelObject *object, const ModelVolume &other) : 
         name(other.name), mesh(other.mesh), config(other.config), modifier(other.modifier), object(object)
         { this->material_id(other.material_id()); }
+    ModelVolume(ModelObject *object, const ModelVolume &other, const TriangleMesh &&mesh) : 
+        name(other.name), mesh(std::move(mesh)), config(other.config), modifier(other.modifier), object(object)
+        { this->material_id(other.material_id()); }
 };
 
 // A single instance of a ModelObject.

xs/src/libslic3r/TriangleMesh.cpp

@@ -78,28 +78,11 @@ TriangleMesh::TriangleMesh(const Pointf3s &points, const std::vector<Point3>& fa
     stl_get_size(&stl);
 }
 
-TriangleMesh::TriangleMesh(const TriangleMesh &other)
-    : stl(other.stl), repaired(other.repaired)
+TriangleMesh::TriangleMesh(const TriangleMesh &other) :
+    repaired(false)
 {
-    this->stl.heads = NULL;
-    this->stl.tail  = NULL;
-    this->stl.error = other.stl.error;
-    if (other.stl.facet_start != NULL) {
-        this->stl.facet_start = (stl_facet*)calloc(other.stl.stats.number_of_facets, sizeof(stl_facet));
-        std::copy(other.stl.facet_start, other.stl.facet_start + other.stl.stats.number_of_facets, this->stl.facet_start);
-    }
-    if (other.stl.neighbors_start != NULL) {
-        this->stl.neighbors_start = (stl_neighbors*)calloc(other.stl.stats.number_of_facets, sizeof(stl_neighbors));
-        std::copy(other.stl.neighbors_start, other.stl.neighbors_start + other.stl.stats.number_of_facets, this->stl.neighbors_start);
-    }
-    if (other.stl.v_indices != NULL) {
-        this->stl.v_indices = (v_indices_struct*)calloc(other.stl.stats.number_of_facets, sizeof(v_indices_struct));
-        std::copy(other.stl.v_indices, other.stl.v_indices + other.stl.stats.number_of_facets, this->stl.v_indices);
-    }
-    if (other.stl.v_shared != NULL) {
-        this->stl.v_shared = (stl_vertex*)calloc(other.stl.stats.shared_vertices, sizeof(stl_vertex));
-        std::copy(other.stl.v_shared, other.stl.v_shared + other.stl.stats.shared_vertices, this->stl.v_shared);
-    }
+    stl_initialize(&this->stl);
+    *this = other;
 }
 
 TriangleMesh::TriangleMesh(TriangleMesh &&other) : 
@@ -109,9 +92,30 @@ TriangleMesh::TriangleMesh(TriangleMesh &&other) :
     this->swap(other);
 }
 
-TriangleMesh& TriangleMesh::operator= (TriangleMesh other)
+TriangleMesh& TriangleMesh::operator=(const TriangleMesh &other)
 {
-    this->swap(other);
+    stl_close(&this->stl);
+    this->stl       = other.stl;
+    this->repaired  = other.repaired;
+    this->stl.heads = nullptr;
+    this->stl.tail  = nullptr;
+    this->stl.error = other.stl.error;
+    if (other.stl.facet_start != nullptr) {
+        this->stl.facet_start = (stl_facet*)calloc(other.stl.stats.number_of_facets, sizeof(stl_facet));
+        std::copy(other.stl.facet_start, other.stl.facet_start + other.stl.stats.number_of_facets, this->stl.facet_start);
+    }
+    if (other.stl.neighbors_start != nullptr) {
+        this->stl.neighbors_start = (stl_neighbors*)calloc(other.stl.stats.number_of_facets, sizeof(stl_neighbors));
+        std::copy(other.stl.neighbors_start, other.stl.neighbors_start + other.stl.stats.number_of_facets, this->stl.neighbors_start);
+    }
+    if (other.stl.v_indices != nullptr) {
+        this->stl.v_indices = (v_indices_struct*)calloc(other.stl.stats.number_of_facets, sizeof(v_indices_struct));
+        std::copy(other.stl.v_indices, other.stl.v_indices + other.stl.stats.number_of_facets, this->stl.v_indices);
+    }
+    if (other.stl.v_shared != nullptr) {
+        this->stl.v_shared = (stl_vertex*)calloc(other.stl.stats.shared_vertices, sizeof(stl_vertex));
+        std::copy(other.stl.v_shared, other.stl.v_shared + other.stl.stats.shared_vertices, this->stl.v_shared);
+    }
     return *this;
 }
 
@@ -427,7 +431,7 @@ TriangleMesh::split() const
     if (!this->repaired) CONFESS("split() requires repair()");
     
     // loop while we have remaining facets
-    while (1) {
+    for (;;) {
         // get the first facet
         std::queue<int> facet_queue;
         std::deque<int> facets;

xs/src/libslic3r/TriangleMesh.hpp

@@ -24,8 +24,8 @@ public:
     TriangleMesh(const Pointf3s &points, const std::vector<Point3> &facets);
     TriangleMesh(const TriangleMesh &other);
     TriangleMesh(TriangleMesh &&other);
-    TriangleMesh& operator= (TriangleMesh other);
-    TriangleMesh& operator= (TriangleMesh &&other);
+    TriangleMesh& operator=(const TriangleMesh &other);
+    TriangleMesh& operator=(TriangleMesh &&other);
     void swap(TriangleMesh &other);
     ~TriangleMesh();
     void ReadSTLFile(const char* input_file);

xs/xsp/Model.xsp

@@ -297,6 +297,8 @@ ModelMaterial::attributes()
         %code%{ RETVAL = THIS->modifier; %};
     void set_modifier(bool modifier)
         %code%{ THIS->modifier = modifier; %};
+
+    size_t split();
     
     ModelMaterial* assign_unique_material();
 };