Add option to add scarf joint to inner walls

src/libslic3r/GCode.cpp

@@ -4541,7 +4541,10 @@ std::string GCode::extrude_loop(ExtrusionLoop loop, std::string description, dou
     } else
         loop.split_at(last_pos, false);
 
-    const bool enable_seam_slope = m_config.seam_slope_enabled.value && !m_config.spiral_mode && loop.role() == erExternalPerimeter && layer_id() > 0;
+    const bool enable_seam_slope = m_config.seam_slope_enabled.value &&
+        !m_config.spiral_mode &&
+        (loop.role() == erExternalPerimeter || (loop.role() == erPerimeter && m_config.seam_slope_inner_walls)) &&
+        layer_id() > 0;
 
     // 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

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_enabled", "seam_slope_start_height", "seam_slope_min_length", "seam_slope_steps",
+     "seam_slope_enabled", "seam_slope_start_height", "seam_slope_min_length", "seam_slope_steps", "seam_slope_inner_walls",
 };
 
 static std::vector<std::string> s_Preset_filament_options {

src/libslic3r/PrintConfig.cpp

@@ -3460,6 +3460,12 @@ def = this->add("filament_loading_speed", coFloats);
     def->mode = comAdvanced;
     def->set_default_value(new ConfigOptionInt(10));
 
+    def = this->add("seam_slope_inner_walls", coBool);
+    def->label = L("Scarf joint for inner walls");
+    def->tooltip = L("Use scarf joint for inner walls as well.");
+    def->mode = comAdvanced;
+    def->set_default_value(new ConfigOptionBool(false));
+
     def = this->add("role_based_wipe_speed", coBool);
     def->label = L("Role base wipe speed");
     def->tooltip = L("The wipe speed is determined by the speed of the current extrusion role."

src/libslic3r/PrintConfig.hpp

@@ -830,6 +830,7 @@ PRINT_CONFIG_CLASS_DEFINE(
     ((ConfigOptionFloatOrPercent,     seam_slope_start_height))
     ((ConfigOptionFloat,              seam_slope_min_length))
     ((ConfigOptionInt,                seam_slope_steps))
+    ((ConfigOptionBool,               seam_slope_inner_walls))
 
 )
 

src/libslic3r/PrintObject.cpp

@@ -1143,6 +1143,7 @@ bool PrintObject::invalidate_state_by_config_options(
             || opt_key == "seam_slope_start_height"
             || opt_key == "seam_slope_min_length"
             || opt_key == "seam_slope_steps"
+            || opt_key == "seam_slope_inner_walls"
             || opt_key == "support_speed"
             || opt_key == "support_interface_speed"
             || opt_key == "overhang_1_4_speed"

src/slic3r/GUI/ConfigManipulation.cpp

@@ -754,6 +754,7 @@ void ConfigManipulation::toggle_print_fff_options(DynamicPrintConfig *config, co
     toggle_line("seam_slope_start_height", has_seam_slope);
     toggle_line("seam_slope_min_length", has_seam_slope);
     toggle_line("seam_slope_steps", has_seam_slope);
+    toggle_line("seam_slope_inner_walls", has_seam_slope);
 }
 
 void ConfigManipulation::update_print_sla_config(DynamicPrintConfig* config, const bool is_global_config/* = false*/)

src/slic3r/GUI/Tab.cpp

@@ -1992,6 +1992,7 @@ void TabPrint::build()
         optgroup->append_single_option_line("seam_slope_start_height");
         optgroup->append_single_option_line("seam_slope_min_length");
         optgroup->append_single_option_line("seam_slope_steps");
+        optgroup->append_single_option_line("seam_slope_inner_walls");
         optgroup->append_single_option_line("role_based_wipe_speed","seam");
         optgroup->append_single_option_line("wipe_speed", "seam");
         optgroup->append_single_option_line("wipe_on_loops","seam");