ENH: use spiral lift only when it is needed

If a travel path goes through an overhang expolygons, and their distance
is shorter than threshold, lift type will be set to SpiralLift.

Signed-off-by: yifan.wu <yifan.wu@bambulab.com>
Change-Id: I345788711755dd8611ecf385818e6052cd8abe9e

src/libslic3r/GCode.cpp

@@ -885,6 +885,9 @@ void GCode::do_export(Print* print, const char* path, GCodeProcessorResult* resu
 {
     PROFILE_CLEAR();
 
+    // BBS
+    m_curr_print = print;
+
     CNumericLocalesSetter locales_setter;
 
     // Does the file exist? If so, we hope that it is still valid.
@@ -3655,7 +3658,8 @@ std::string GCode::travel_to(const Point &point, ExtrusionRole role, std::string
     Polyline travel { this->last_pos(), point };
 
     // check whether a straight travel move would need retraction
-    bool needs_retraction             = this->needs_retraction(travel, role);
+    LiftType lift_type = LiftType::SpiralLift;
+    bool needs_retraction = this->needs_retraction(travel, role, lift_type);
     // check whether wipe could be disabled without causing visible stringing
     bool could_be_wipe_disabled       = false;
     // Save state of use_external_mp_once for the case that will be needed to call twice m_avoid_crossing_perimeters.travel_to.
@@ -3670,10 +3674,15 @@ std::string GCode::travel_to(const Point &point, ExtrusionRole role, std::string
         && m_writer.is_current_position_clear()) {
         travel = m_avoid_crossing_perimeters.travel_to(*this, point, &could_be_wipe_disabled);
         // check again whether the new travel path still needs a retraction
-        needs_retraction = this->needs_retraction(travel, role);
+        needs_retraction = this->needs_retraction(travel, role, lift_type);
         //if (needs_retraction && m_layer_index > 1) exit(0);
     }
 
+    if (lift_type == LiftType::LazyLift)
+        printf("lazy lift\n");
+    else if (lift_type == LiftType::SpiralLift)
+        printf("spiral lift\n");
+
     // Re-allow reduce_crossing_wall for the next travel moves
     m_avoid_crossing_perimeters.reset_once_modifiers();
 
@@ -3684,7 +3693,7 @@ std::string GCode::travel_to(const Point &point, ExtrusionRole role, std::string
             m_wipe.reset_path();
 
         Point last_post_before_retract = this->last_pos();
-        gcode += this->retract();
+        gcode += this->retract(false, false, lift_type);
         // When "Wipe while retracting" is enabled, then extruder moves to another position, and travel from this position can cross perimeters.
         // Because of it, it is necessary to call avoid crossing perimeters again with new starting point after calling retraction()
         // FIXME Lukas H.: Try to predict if this second calling of avoid crossing perimeters will be needed or not. It could save computations.
@@ -3719,35 +3728,100 @@ std::string GCode::travel_to(const Point &point, ExtrusionRole role, std::string
     return gcode;
 }
 
-bool GCode::needs_retraction(const Polyline &travel, ExtrusionRole role)
+bool GCode::needs_retraction(const Polyline &travel, ExtrusionRole role, LiftType& lift_type)
 {
     if (travel.length() < scale_(EXTRUDER_CONFIG(retraction_minimum_travel))) {
         // skip retraction if the move is shorter than the configured threshold
         return false;
     }
 
+    auto is_through_overhang = [this](const Polyline& travel) {
+        const float protect_z_scaled = scale_(0.4);
+        std::pair<float, float> z_range;
+        z_range.second = m_layer ? m_layer->print_z : 0.f;
+        z_range.first = std::max(0.f, z_range.second - protect_z_scaled);
+        for (auto object : m_curr_print->objects()) {
+            BoundingBox obj_bbox = object->bounding_box();
+            BoundingBox travel_bbox = get_extents(travel);
+            obj_bbox.offset(scale_(EPSILON));
+            if (!obj_bbox.overlap(travel_bbox))
+                continue;
+
+            for (auto layer : object->layers()) {
+                if (layer->print_z < z_range.first)
+                    continue;
+
+                if (layer->print_z > z_range.second + EPSILON)
+                    break;
+
+                for (ExPolygon& overhang : layer->loverhangs) {
+                    if (overhang.contains(travel))
+                        return true;
+                }
+            }
+        }
+
+        return false;
+    };
+
+    auto to_lift_type = [](ZHopType z_hop_type) {
+        if (z_hop_type == ZHopType::zhtNormal)
+            return LiftType::NormalLift;
+
+        if (z_hop_type == ZHopType::zhtSlope)
+            return LiftType::LazyLift;
+
+        if (z_hop_type == ZHopType::zhtSpiral)
+            return LiftType::SpiralLift;
+
+        // if no corresponding lift type, use normal lift
+        return LiftType::NormalLift;
+    };
+
+    float max_z_hop = 0.f;
+    for (int i = 0; i < m_config.z_hop.size(); i++)
+        max_z_hop = std::max(max_z_hop, (float)m_config.z_hop.get_at(i));
+    float travel_len_thresh = max_z_hop / tan(GCodeWriter::slope_threshold);
+    float accum_len = 0.f;
+    Polyline clipped_travel;
+    for (auto line : travel.lines()) {
+        if (accum_len + line.length() > travel_len_thresh + EPSILON) {
+            Point end_pnt = line.a + line.normal() * (travel_len_thresh - accum_len);
+            clipped_travel.append(Polyline(line.a, end_pnt));
+            break;
+        }
+        else {
+            clipped_travel.append(Polyline(line.a, line.b));
+            accum_len += line.length();
+        }
+    }
+
     //BBS: force to retract when leave from external perimeter for a long travel
     //Better way is judging whether the travel move direction is same with last extrusion move.
-    if (is_perimeter(m_last_processor_extrusion_role) && m_last_processor_extrusion_role != erPerimeter)
+    if (is_perimeter(m_last_processor_extrusion_role) && m_last_processor_extrusion_role != erPerimeter) {
+        if (m_config.z_hop_type == ZHopType::zhtAuto) {
+            lift_type = is_through_overhang(clipped_travel) ? LiftType::SpiralLift : LiftType::LazyLift;
+        }
+        else {
+            lift_type = to_lift_type(m_config.z_hop_type);
+        }
         return true;
+    }
 
     if (role == erSupportMaterial || role == erSupportTransition) {
         const SupportLayer* support_layer = dynamic_cast<const SupportLayer*>(m_layer);
-
         //FIXME support_layer->support_islands.contains should use some search structure!
         if (support_layer != NULL && support_layer->support_islands.contains(travel))
             // skip retraction if this is a travel move inside a support material island
             //FIXME not retracting over a long path may cause oozing, which in turn may result in missing material
             // at the end of the extrusion path!
             return false;
-
         //reduce the retractions in lightning infills for tree support
         if (support_layer != NULL && support_layer->support_type==stInnerTree)
             for (auto &area : support_layer->base_areas)
                 if (area.contains(travel))
                     return false;
     }
-
     //BBS: need retract when long moving to print perimeter to avoid dropping of material
     if (!is_perimeter(role) && m_config.reduce_infill_retraction && m_layer != nullptr &&
         m_config.sparse_infill_density.value > 0 && m_layer->any_internal_region_slice_contains(travel))
@@ -3757,10 +3831,16 @@ bool GCode::needs_retraction(const Polyline &travel, ExtrusionRole role)
         return false;
 
     // retract if reduce_infill_retraction is disabled or doesn't apply when role is perimeter
+    if (m_config.z_hop_type == ZHopType::zhtAuto) {
+        lift_type = is_through_overhang(clipped_travel) ? LiftType::SpiralLift : LiftType::LazyLift;
+    }
+    else {
+        lift_type = to_lift_type(m_config.z_hop_type);
+    }
     return true;
 }
 
-std::string GCode::retract(bool toolchange, bool is_last_retraction)
+std::string GCode::retract(bool toolchange, bool is_last_retraction, LiftType lift_type)
 {
     std::string gcode;
 
@@ -3784,7 +3864,7 @@ std::string GCode::retract(bool toolchange, bool is_last_retraction)
     if (m_writer.extruder()->retraction_length() > 0) {
         // BBS: don't do lazy_lift when enable spiral vase
         size_t extruder_id = m_writer.extruder()->id();
-        gcode += m_writer.lift(!m_spiral_vase ?  LiftType::SpiralLift : LiftType::NormalLift);
+        gcode += m_writer.lift(!m_spiral_vase ? lift_type : LiftType::NormalLift);
     }
 
     return gcode;

src/libslic3r/GCode.hpp

@@ -395,8 +395,9 @@ private:
     std::string     extrude_support(const ExtrusionEntityCollection &support_fills);
 
     std::string     travel_to(const Point &point, ExtrusionRole role, std::string comment);
-    bool            needs_retraction(const Polyline &travel, ExtrusionRole role = erNone);
-    std::string     retract(bool toolchange = false, bool is_last_retraction = false);
+    // BBS: detect lift type in needs_retraction
+    bool            needs_retraction(const Polyline& travel, ExtrusionRole role, LiftType& lift_type);
+    std::string     retract(bool toolchange = false, bool is_last_retraction = false, LiftType lift_type = LiftType::SpiralLift);
     std::string     unretract() { return m_writer.unlift() + m_writer.unretract(); }
     std::string     set_extruder(unsigned int extruder_id, double print_z);
     std::set<ObjectID>              m_objsWithBrim; // indicates the objs with brim
@@ -477,6 +478,7 @@ private:
     GCodeProcessor m_processor;
 
     // BBS
+    Print* m_curr_print = nullptr;
     unsigned int m_toolchange_count;
     coordf_t m_nominal_z;
     bool m_need_change_layer_lift_z = false;

src/libslic3r/GCodeWriter.hpp

@@ -93,6 +93,8 @@ public:
     bool is_current_position_clear() const { return m_is_current_pos_clear; };
     //BBS:
     static const bool full_gcode_comment;
+    //Radian threshold of slope for lazy lift and spiral lift;
+    static const double slope_threshold;
 
 private:
 	// Extruders are sorted by their ID, so that binary search is possible.
@@ -121,9 +123,6 @@ private:
     double          m_x_offset{ 0 };
     double          m_y_offset{ 0 };
 
-    //Radian threshold of slope for lazy lift and spiral lift;
-    static const double slope_threshold;
-
     std::string _travel_to_z(double z, const std::string &comment);
     std::string _spiral_travel_to_z(double z, const Vec2d &ij_offset, const std::string &comment);
     std::string _retract(double length, double restart_extra, const std::string &comment);

src/libslic3r/Layer.hpp

@@ -143,6 +143,9 @@ public:
     ExPolygons 				 lslices;
     std::vector<BoundingBox> lslices_bboxes;
 
+    // BBS
+    ExPolygons              loverhangs;
+
     size_t                  region_count() const { return m_regions.size(); }
     const LayerRegion*      get_region(int idx) const { return m_regions[idx]; }
     LayerRegion*            get_region(int idx) { return m_regions[idx]; }

src/libslic3r/Preset.cpp

@@ -789,7 +789,7 @@ static std::vector<std::string> s_Preset_printer_options {
     "silent_mode",
     // BBS
     "scan_first_layer", "machine_load_filament_time", "machine_unload_filament_time", "machine_pause_gcode", "template_custom_gcode",
-    "nozzle_type", "nozzle_hrc","auxiliary_fan", "nozzle_volume","upward_compatible_machine",
+    "nozzle_type", "nozzle_hrc","auxiliary_fan", "nozzle_volume","upward_compatible_machine", "z_hop_type",
     //SoftFever
     "host_type", "print_host", "printhost_apikey", 
     "printhost_cafile","printhost_port","printhost_authorization_type",

src/libslic3r/Print.cpp

@@ -224,6 +224,9 @@ bool Print::invalidate_state_by_config_options(const ConfigOptionResolver & /* n
             osteps.emplace_back(posSimplifyPath);
             osteps.emplace_back(posSimplifySupportPath);
             steps.emplace_back(psSkirtBrim);
+        }
+        else if (opt_key == "z_hop_type") {
+            osteps.emplace_back(posDetectOverhangsForLift);
         } else {
             // for legacy, if we can't handle this option let's invalidate all steps
             //FIXME invalidate all steps of all objects as well?
@@ -1631,6 +1634,17 @@ void Print::process(bool use_cache)
         }
     }
 
+    // BBS
+    for (PrintObject* obj : m_objects) {
+        if (need_slicing_objects.count(obj) != 0) {
+            obj->detect_overhangs_for_lift();
+        }
+        else {
+            if (obj->set_started(posDetectOverhangsForLift))
+                obj->set_done(posDetectOverhangsForLift);
+        }
+    }
+
     BOOST_LOG_TRIVIAL(info) << "Slicing process finished." << log_memory_info();
 }
 

src/libslic3r/Print.hpp

@@ -84,7 +84,10 @@ enum PrintStep {
 
 enum PrintObjectStep {
     posSlice, posPerimeters, posPrepareInfill,
-    posInfill, posIroning, posSupportMaterial, posSimplifyPath, posSimplifySupportPath, posCount,
+    posInfill, posIroning, posSupportMaterial, posSimplifyPath, posSimplifySupportPath,
+    // BBS
+    posDetectOverhangsForLift,
+    posCount,
 };
 
 // A PrintRegion object represents a group of volumes to print
@@ -445,6 +448,10 @@ private:
     void slice_volumes();
     //BBS
     ExPolygons _shrink_contour_holes(double contour_delta, double hole_delta, const ExPolygons& polys) const;
+    // BBS
+    void detect_overhangs_for_lift();
+    void clear_overhangs_for_lift();
+
     // Has any support (not counting the raft).
     void detect_surfaces_type();
     void process_external_surfaces();

src/libslic3r/PrintConfig.cpp

@@ -292,6 +292,14 @@ static t_config_enum_values s_keys_map_PerimeterGeneratorType{
 };
 CONFIG_OPTION_ENUM_DEFINE_STATIC_MAPS(PerimeterGeneratorType)
 
+static const t_config_enum_values s_keys_map_ZHopType = {
+    { "Auto Lift",          zhtAuto },
+    { "Normal Lift",        zhtNormal },
+    { "Slope Lift",         zhtSlope },
+    { "Spiral Lift",        zhtSpiral }
+};
+CONFIG_OPTION_ENUM_DEFINE_STATIC_MAPS(ZHopType)
+
 static void assign_printer_technology_to_unknown(t_optiondef_map &options, PrinterTechnology printer_technology)
 {
     for (std::pair<const t_config_option_key, ConfigOptionDef> &kvp : options)
@@ -2127,6 +2135,21 @@ void PrintConfigDef::init_fff_params()
     def->mode = comSimple;
     def->set_default_value(new ConfigOptionFloats { 0.4 });
 
+    def = this->add("z_hop_type", coEnum);
+    def->label = L("Z Hop Type");
+    def->tooltip = L("");
+    def->enum_keys_map = &ConfigOptionEnum<ZHopType>::get_enum_values();
+    def->enum_values.push_back("auto");
+    def->enum_values.push_back("normal");
+    def->enum_values.push_back("slope");
+    def->enum_values.push_back("spiral");
+    def->enum_labels.push_back(L("Auto"));
+    def->enum_labels.push_back(L("Normal"));
+    def->enum_labels.push_back(L("Slope"));
+    def->enum_labels.push_back(L("Spiral"));
+    def->mode = comAdvanced;
+    def->set_default_value(new ConfigOptionEnum{ ZHopType::zhtSpiral });
+
     def = this->add("retract_restart_extra", coFloats);
     //def->label = L("Extra length on restart");
     def->label = "Extra length on restart";

src/libslic3r/PrintConfig.hpp

@@ -200,6 +200,15 @@ enum NozzleType {
     ntCount
 };
 
+// BBS
+enum ZHopType {
+    zhtAuto = 0,
+    zhtNormal,
+    zhtSlope,
+    zhtSpiral,
+    zhtCount
+};
+
 static std::string bed_type_to_gcode_string(const BedType type)
 {
     std::string type_str;
@@ -812,6 +821,8 @@ PRINT_CONFIG_CLASS_DEFINE(
     ((ConfigOptionFloats,              retraction_length))
     ((ConfigOptionFloats,              retract_length_toolchange))
     ((ConfigOptionFloats,              z_hop))
+    // BBS
+    ((ConfigOptionEnum<ZHopType>,      z_hop_type))
     ((ConfigOptionFloats,              retract_restart_extra))
     ((ConfigOptionFloats,              retract_restart_extra_toolchange))
     ((ConfigOptionFloats,              retraction_speed))

src/libslic3r/PrintObject.cpp

@@ -409,6 +409,48 @@ void PrintObject::ironing()
     }
 }
 
+// BBS
+void PrintObject::clear_overhangs_for_lift()
+{
+    if (!m_shared_object) {
+        for (Layer* l : m_layers)
+            l->loverhangs.clear();
+    }
+}
+
+static const float g_min_overhang_percent_for_lift = 0.3f;
+
+void PrintObject::detect_overhangs_for_lift()
+{
+    if (this->set_started(posDetectOverhangsForLift)) {
+        const float min_overlap = m_config.line_width * g_min_overhang_percent_for_lift;
+        size_t num_layers = this->layer_count();
+        size_t num_raft_layers = m_slicing_params.raft_layers();
+
+        m_print->set_status(78, L("Detect overhangs for auto-lift"));
+
+        this->clear_overhangs_for_lift();
+
+        if (m_print->config().z_hop_type != ZHopType::zhtAuto)
+            return;
+
+        tbb::spin_mutex layer_storage_mutex;
+        tbb::parallel_for(tbb::blocked_range<size_t>(num_raft_layers + 1, num_layers),
+            [this, min_overlap](const tbb::blocked_range<size_t>& range)
+            {
+                for (size_t layer_id = range.begin(); layer_id < range.end(); ++layer_id) {
+                    Layer& layer = *m_layers[layer_id];
+                    Layer& lower_layer = *layer.lower_layer;
+
+                    ExPolygons overhangs = diff_ex(layer.lslices, offset_ex(lower_layer.lslices, scale_(min_overlap)));
+                    layer.loverhangs = std::move(offset2_ex(overhangs, -0.1f * scale_(m_config.line_width), 0.1f * scale_(m_config.line_width)));
+                }
+            });
+
+        this->set_done(posDetectOverhangsForLift);
+    }
+}
+
 void PrintObject::generate_support_material()
 {
     if (this->set_started(posSupportMaterial)) {

src/slic3r/GUI/Tab.cpp

@@ -3319,6 +3319,7 @@ void TabPrinter::build_unregular_pages(bool from_initial_build/* = false*/)
             optgroup = page->new_optgroup(L("Retraction"), L"param_retraction");
             optgroup->append_single_option_line("retraction_length", "", extruder_idx);
             optgroup->append_single_option_line("z_hop", "", extruder_idx);
+            optgroup->append_single_option_line("z_hop_type", "");
             optgroup->append_single_option_line("retraction_speed", "", extruder_idx);
             optgroup->append_single_option_line("deretraction_speed", "", extruder_idx);
             //optgroup->append_single_option_line("retract_restart_extra", "", extruder_idx);