Add overhang threshold for scarf joint seam (#4725)

add overhang threshold for scarf joint seam

src/libslic3r/GCode.cpp

@@ -4549,10 +4549,11 @@ std::string GCode::extrude_loop(ExtrusionLoop loop, std::string description, dou
     // find the point of the loop that is closest to the current extruder position
     // or randomize if requested
     Point last_pos = this->last_pos();
+    float seam_overhang = std::numeric_limits<float>::lowest();
     if (!m_config.spiral_mode && description == "perimeter") {
         assert(m_layer != nullptr);
         bool is_outer_wall_first = m_config.wall_sequence == WallSequence::OuterInner;
-        m_seam_placer.place_seam(m_layer, loop, is_outer_wall_first, this->last_pos());
+        m_seam_placer.place_seam(m_layer, loop, is_outer_wall_first, this->last_pos(), seam_overhang);
     } else
         loop.split_at(last_pos, false);
 
@@ -4561,14 +4562,21 @@ std::string GCode::extrude_loop(ExtrusionLoop loop, std::string description, dou
         !m_config.spiral_mode &&
         (loop.role() == erExternalPerimeter || (loop.role() == erPerimeter && m_config.seam_slope_inner_walls)) &&
         layer_id() > 0;
-
+    const auto nozzle_diameter = EXTRUDER_CONFIG(nozzle_diameter);
     if (enable_seam_slope && m_config.seam_slope_conditional.value) {
-        enable_seam_slope = loop.is_smooth(m_config.scarf_angle_threshold.value * M_PI / 180., EXTRUDER_CONFIG(nozzle_diameter));
+        enable_seam_slope = loop.is_smooth(m_config.scarf_angle_threshold.value * M_PI / 180., nozzle_diameter);
     }
+
+    if (enable_seam_slope && m_config.seam_slope_conditional.value && m_config.scarf_overhang_threshold.value > 0.0f) {
+        const auto _line_width = loop.role() == erExternalPerimeter ? m_config.outer_wall_line_width.get_abs_value(nozzle_diameter) :
+                                                                      m_config.inner_wall_line_width.get_abs_value(nozzle_diameter);
+        enable_seam_slope      = seam_overhang < m_config.scarf_overhang_threshold.value * 0.01f * _line_width;
+    }
+
     // clip the path to avoid the extruder to get exactly on the first point of the loop;
     // if polyline was shorter than the clipping distance we'd get a null polyline, so
     // we discard it in that case
-    const double seam_gap = scale_(m_config.seam_gap.get_abs_value(EXTRUDER_CONFIG(nozzle_diameter)));
+    const double seam_gap = scale_(m_config.seam_gap.get_abs_value(nozzle_diameter));
     const double clip_length = m_enable_loop_clipping && !enable_seam_slope ? seam_gap : 0;
 
     // get paths
@@ -4596,7 +4604,7 @@ std::string GCode::extrude_loop(ExtrusionLoop loop, std::string description, dou
     if (m_config.wipe_before_external_loop.value && !paths.empty() && paths.front().size() > 1 && paths.back().size() > 1 && paths.front().role() == erExternalPerimeter && region_perimeters.size() > 1) {
         const bool is_full_loop_ccw = loop.polygon().is_counter_clockwise();
         bool is_hole_loop = (loop.loop_role() & ExtrusionLoopRole::elrHole) != 0; // loop.make_counter_clockwise();
-        const double nozzle_diam = EXTRUDER_CONFIG(nozzle_diameter);
+        const double nozzle_diam = nozzle_diameter;
 
         // note: previous & next are inverted to extrude "in the opposite direction, and we are "rewinding"
         Point previous_point = paths.front().polyline.points[1];

src/libslic3r/GCode/SeamPlacer.cpp

@@ -1067,15 +1067,18 @@ void SeamPlacer::calculate_overhangs_and_layer_embedding(const PrintObject *po)
                         std::unique_ptr<PerimeterDistancer> current_layer_distancer        = std::make_unique<PerimeterDistancer>(
                             to_unscaled_linesf(po->layers()[layer_idx]->lslices));
 
-                        for (SeamCandidate &perimeter_point : layers[layer_idx].points) {
+                        auto& layer_seams = layers[layer_idx];
+                        for (SeamCandidate &perimeter_point : layer_seams.points) {
                           Vec2f point = Vec2f { perimeter_point.position.head<2>() };
                           if (prev_layer_distancer.get() != nullptr) {
-                            perimeter_point.overhang = prev_layer_distancer->distance_from_lines<true>(point.cast<double>())
+                            const auto _dist = prev_layer_distancer->distance_from_lines<true>(point.cast<double>());
+                            perimeter_point.overhang = _dist
                                                        + 0.6f * perimeter_point.perimeter.flow_width
                                                        - tan(SeamPlacer::overhang_angle_threshold)
                                                              * po->layers()[layer_idx]->height;
                             perimeter_point.overhang =
                                 perimeter_point.overhang < 0.0f ? 0.0f : perimeter_point.overhang;
+                            perimeter_point.unsupported_dist = _dist + 0.4f * perimeter_point.perimeter.flow_width;
                           }
 
                           if (should_compute_layer_embedding) { // search for embedded perimeter points (points hidden inside the print ,e.g. multimaterial join, best position for seam)
@@ -1484,7 +1487,7 @@ void SeamPlacer::init(const Print &print, std::function<void(void)> throw_if_can
 }
 
 void SeamPlacer::place_seam(const Layer *layer, ExtrusionLoop &loop, bool external_first,
-                            const Point &last_pos) const {
+                            const Point &last_pos, float& overhang) const {
   using namespace SeamPlacerImpl;
   const PrintObject *po = layer->object();
   // Must not be called with supprot layer.
@@ -1546,6 +1549,7 @@ void SeamPlacer::place_seam(const Layer *layer, ExtrusionLoop &loop, bool extern
   }
 
   Point seam_point = Point::new_scale(seam_position.x(), seam_position.y());
+  overhang = layer_perimeters.points[seam_index].unsupported_dist;
 
   if (loop.role() == ExtrusionRole::erPerimeter) { //Hopefully inner perimeter
     const SeamCandidate &perimeter_point = layer_perimeters.points[seam_index];

src/libslic3r/GCode/SeamPlacer.hpp

@@ -1,6 +1,7 @@
 #ifndef libslic3r_SeamPlacer_hpp_
 #define libslic3r_SeamPlacer_hpp_
 
+#include <limits>
 #include <optional>
 #include <vector>
 #include <memory>
@@ -66,6 +67,7 @@ struct SeamCandidate {
   Perimeter &perimeter;
   float visibility;
   float overhang;
+  float unsupported_dist;
   // distance inside the merged layer regions, for detecting perimeter points which are hidden indside the print (e.g. multimaterial join)
   // Negative sign means inside the print, comes from EdgeGrid structure
   float embedded_distance;
@@ -141,8 +143,7 @@ public:
 
   void init(const Print &print, std::function<void(void)> throw_if_canceled_func);
 
-  void place_seam(const Layer *layer, ExtrusionLoop &loop, bool external_first, const Point &last_pos) const;
+  void place_seam(const Layer *layer, ExtrusionLoop &loop, bool external_first, const Point &last_pos, float& overhang) const;
-
 private:
   void gather_seam_candidates(const PrintObject *po, const SeamPlacerImpl::GlobalModelInfo &global_model_info);
   void calculate_candidates_visibility(const PrintObject *po,

src/libslic3r/Layer.cpp

@@ -188,6 +188,7 @@ void Layer::make_perimeters()
                         && config.seam_slope_type         == other_config.seam_slope_type
                         && config.seam_slope_conditional == other_config.seam_slope_conditional
                         && config.scarf_angle_threshold  == other_config.scarf_angle_threshold
+                        && config.scarf_overhang_threshold  == other_config.scarf_overhang_threshold
                         && config.scarf_joint_speed       == other_config.scarf_joint_speed
                         && config.scarf_joint_flow_ratio       == other_config.scarf_joint_flow_ratio
                         && config.seam_slope_start_height == other_config.seam_slope_start_height

src/libslic3r/Preset.cpp

@@ -820,7 +820,7 @@ static std::vector<std::string> s_Preset_print_options {
      "wipe_tower_rotation_angle", "tree_support_branch_distance_organic", "tree_support_branch_diameter_organic", "tree_support_branch_angle_organic",
      "hole_to_polyhole", "hole_to_polyhole_threshold", "hole_to_polyhole_twisted", "mmu_segmented_region_max_width", "mmu_segmented_region_interlocking_depth",
      "small_area_infill_flow_compensation", "small_area_infill_flow_compensation_model",
-     "seam_slope_type", "seam_slope_conditional", "scarf_angle_threshold", "scarf_joint_speed", "scarf_joint_flow_ratio", "seam_slope_start_height", "seam_slope_entire_loop", "seam_slope_min_length", "seam_slope_steps", "seam_slope_inner_walls",
+     "seam_slope_type", "seam_slope_conditional", "scarf_angle_threshold", "scarf_joint_speed", "scarf_joint_flow_ratio", "seam_slope_start_height", "seam_slope_entire_loop", "seam_slope_min_length", "seam_slope_steps", "seam_slope_inner_walls", "scarf_overhang_threshold"
 };
 
 static std::vector<std::string> s_Preset_filament_options {

src/libslic3r/PrintConfig.cpp

@@ -3588,6 +3588,17 @@ def = this->add("filament_loading_speed", coFloats);
     def->max = 180;
     def->set_default_value(new ConfigOptionInt(155));
 
+    def = this->add("scarf_overhang_threshold", coPercent);
+    def->label = L("Conditional overhang threshold");
+    def->category = L("Quality");
+    def->tooltip  = L("This option determines the overhang threshold for the application of scarf joint seams. If the unsupported portion "
+                       "of the perimeter is less than this threshold, scarf joint seams will be applied. The default threshold is set at 40% "
+                       "of the external wall's width. Due to performance considerations, the degree of overhang is estimated.");
+    def->sidetext = L("%");
+    def->min = 0;
+    def->mode = comAdvanced;
+    def->set_default_value(new ConfigOptionPercent(40));
+
     def = this->add("scarf_joint_speed", coFloatOrPercent);
     def->label = L("Scarf joint speed");
     def->category = L("Quality");
@@ -3605,7 +3616,7 @@ def = this->add("filament_loading_speed", coFloats);
     def = this->add("scarf_joint_flow_ratio", coFloat);
     def->label = L("Scarf joint flow ratio");
     def->tooltip = L("This factor affects the amount of material for scarf joints.");
-    def->mode = comAdvanced;
+    def->mode = comDevelop;
     def->max = 2;
     def->set_default_value(new ConfigOptionFloat(1));
 

src/libslic3r/PrintConfig.hpp

@@ -969,6 +969,7 @@ PRINT_CONFIG_CLASS_DEFINE(
     ((ConfigOptionBool,                 seam_slope_inner_walls))
     ((ConfigOptionFloatOrPercent,       scarf_joint_speed))
     ((ConfigOptionFloat,                scarf_joint_flow_ratio))
+    ((ConfigOptionPercent,              scarf_overhang_threshold))
 
 
 )

src/libslic3r/PrintObject.cpp

@@ -1145,6 +1145,7 @@ bool PrintObject::invalidate_state_by_config_options(
             || opt_key == "seam_slope_type"
             || opt_key == "seam_slope_conditional"
             || opt_key == "scarf_angle_threshold"
+            || opt_key == "scarf_overhang_threshold"
             || opt_key == "scarf_joint_speed"
             || opt_key == "scarf_joint_flow_ratio"
             || opt_key == "seam_slope_start_height"

src/slic3r/GUI/ConfigManipulation.cpp

@@ -764,6 +764,7 @@ void ConfigManipulation::toggle_print_fff_options(DynamicPrintConfig *config, co
     toggle_line("scarf_joint_flow_ratio", has_seam_slope);
     toggle_field("seam_slope_min_length", !config->opt_bool("seam_slope_entire_loop"));
     toggle_line("scarf_angle_threshold", has_seam_slope && config->opt_bool("seam_slope_conditional"));
+    toggle_line("scarf_overhang_threshold", has_seam_slope && config->opt_bool("seam_slope_conditional"));
 }
 
 void ConfigManipulation::update_print_sla_config(DynamicPrintConfig* config, const bool is_global_config/* = false*/)

src/slic3r/GUI/Tab.cpp

@@ -1979,6 +1979,7 @@ void TabPrint::build()
         optgroup->append_single_option_line("seam_slope_type", "seam#scarf-joint-seam");
         optgroup->append_single_option_line("seam_slope_conditional", "seam#scarf-joint-seam");
         optgroup->append_single_option_line("scarf_angle_threshold", "seam#scarf-joint-seam");
+        optgroup->append_single_option_line("scarf_overhang_threshold", "seam#scarf-joint-seam");
         optgroup->append_single_option_line("scarf_joint_speed", "seam#scarf-joint-seam");
         optgroup->append_single_option_line("seam_slope_start_height", "seam#scarf-joint-seam");
         optgroup->append_single_option_line("seam_slope_entire_loop", "seam#scarf-joint-seam");