Introduce option to control whether one or multiple skirt walls after first layer are extruded

src/libslic3r/GCode.cpp

@@ -3538,7 +3538,18 @@ std::string GCode::generate_skirt(const Print &print,
         m_avoid_crossing_perimeters.use_external_mp();
         Flow layer_skirt_flow = print.skirt_flow().with_height(float(m_skirt_done.back() - (m_skirt_done.size() == 1 ? 0. : m_skirt_done[m_skirt_done.size() - 2])));
         double mm3_per_mm = layer_skirt_flow.mm3_per_mm();
-        for (size_t i = first_layer ? loops.first : loops.second - 1; i < loops.second; ++i) {
+        // Decide where to start looping:
+        // - If it’s the first layer or if we do NOT want a single-wall draft shield,
+        //   start from loops.first (all loops).
+        // - Otherwise, if one_wall_draft_shield == true (and not the first layer),
+        //   start from loops.second - 1 (just one loop).
+        bool one_wall_draft_shield = print.m_config.one_wall_draft_shield;
+        const size_t start_idx = (first_layer || !one_wall_draft_shield)
+                                 ? loops.first
+                                 : (loops.second - 1);
+
+        // Loop over the skirt loops and extrude
+        for (size_t i = start_idx; i < loops.second; ++i) {
             // Adjust flow according to this layer's layer height.
             ExtrusionLoop loop = *dynamic_cast<const ExtrusionLoop*>(skirt.entities[i]);
             for (ExtrusionPath &path : loop.paths) {
@@ -3552,8 +3563,10 @@ std::string GCode::generate_skirt(const Print &print,
 
             //FIXME using the support_speed of the 1st object printed.
             gcode += this->extrude_loop(loop, "skirt", m_config.support_speed.value);
-            if (!first_layer)
+            // If we only want a single wall on non-first layers, break now
+            if (!first_layer && one_wall_draft_shield) {
                 break;
+            }
         }
         m_avoid_crossing_perimeters.use_external_mp(false);
         // Allow a straight travel move to the first object point if this is the first layer (but don't in next layers).
@@ -4583,8 +4596,8 @@ std::string GCode::extrude_loop(ExtrusionLoop loop, std::string description, dou
         // if spiral vase, we have to ensure that all contour are in the same orientation.
         loop.make_counter_clockwise();
     }
-    if (loop.loop_role() == elrSkirt && (this->m_layer->id() % 2 == 1))
-        loop.reverse();
+    //if (loop.loop_role() == elrSkirt && (this->m_layer->id() % 2 == 1))
+    //    loop.reverse();
 
     // find the point of the loop that is closest to the current extruder position
     // or randomize if requested

src/libslic3r/Preset.cpp

@@ -796,7 +796,7 @@ static std::vector<std::string> s_Preset_print_options {
     "inner_wall_speed", "outer_wall_speed", "sparse_infill_speed", "internal_solid_infill_speed",
     "top_surface_speed", "support_speed", "support_object_xy_distance", "support_object_first_layer_gap", "support_interface_speed",
     "bridge_speed", "internal_bridge_speed", "gap_infill_speed", "travel_speed", "travel_speed_z", "initial_layer_speed",
-    "outer_wall_acceleration", "initial_layer_acceleration", "top_surface_acceleration", "default_acceleration", "skirt_type", "skirt_loops", "skirt_speed","min_skirt_length", "skirt_distance", "skirt_start_angle", "skirt_height", "draft_shield",
+    "outer_wall_acceleration", "initial_layer_acceleration", "top_surface_acceleration", "default_acceleration", "skirt_type", "skirt_loops", "skirt_speed","min_skirt_length", "skirt_distance", "skirt_start_angle", "skirt_height","one_wall_draft_shield", "draft_shield",
     "brim_width", "brim_object_gap", "brim_type", "brim_ears_max_angle", "brim_ears_detection_length", "enable_support", "support_type", "support_threshold_angle", "support_threshold_overlap","enforce_support_layers",
     "raft_layers", "raft_first_layer_density", "raft_first_layer_expansion", "raft_contact_distance", "raft_expansion",
     "support_base_pattern", "support_base_pattern_spacing", "support_expansion", "support_style",

src/libslic3r/Print.cpp

@@ -228,6 +228,7 @@ bool Print::invalidate_state_by_config_options(const ConfigOptionResolver & /* n
             || opt_key == "skirt_speed"
             || opt_key == "skirt_height"
             || opt_key == "min_skirt_length"
+            || opt_key == "one_wall_draft_shield"
             || opt_key == "draft_shield"
             || opt_key == "skirt_distance"
             || opt_key == "skirt_start_angle"

src/libslic3r/PrintConfig.cpp

@@ -4288,6 +4288,12 @@ void PrintConfigDef::init_fff_params()
     def->mode = comSimple;
     def->max = 10000;
     def->set_default_value(new ConfigOptionInt(1));
+
+    def = this->add("one_wall_draft_shield", coBool);
+    def->label = L("One wall skirt after first layer");
+    def->tooltip = L("Limits the skirt loops to one wall after the first skirt layer. This is useful, on occasion, to conserve filament when using a draft shield.");
+    def->mode = comAdvanced;
+    def->set_default_value(new ConfigOptionBool(false));
 
     def = this->add("draft_shield", coEnum);
     def->label = L("Draft shield");

src/libslic3r/PrintConfig.hpp

@@ -1286,6 +1286,7 @@ PRINT_CONFIG_CLASS_DERIVED_DEFINE(
     ((ConfigOptionInt,                skirt_loops))
     ((ConfigOptionEnum<SkirtType>,    skirt_type))
     ((ConfigOptionFloat,              skirt_speed))
+    ((ConfigOptionBool,               one_wall_draft_shield))
     ((ConfigOptionFloat,              min_skirt_length))
     ((ConfigOptionFloats,             slow_down_layer_time))
     ((ConfigOptionBool,               spiral_mode))

src/slic3r/GUI/Tab.cpp

@@ -2308,6 +2308,7 @@ page = add_options_page(L("Others"), "custom-gcode_other"); // ORCA: icon only v
         optgroup->append_single_option_line("skirt_distance");
         optgroup->append_single_option_line("skirt_start_angle");
         optgroup->append_single_option_line("skirt_height");
+        optgroup->append_single_option_line("one_wall_draft_shield");
         optgroup->append_single_option_line("skirt_speed");
         optgroup->append_single_option_line("draft_shield");