[FEATURE] Only one perimeter on first layer

src/libslic3r/PerimeterGenerator.cpp

@@ -1116,6 +1116,9 @@ void PerimeterGenerator::process_arachne(
     // extra perimeters for each one
     // detect how many perimeters must be generated for this island
     int        loop_number = params.config.perimeters + surface.extra_perimeters - 1; // 0-indexed loops
+    // SuperSlicer: set the bottommost layer to be one perimeter
+    if (params.layer_id == 0 && params.config.only_one_perimeter_first_layer)
+        loop_number = 0;
     // SuperSlicer: set the topmost layer to be one perimeter
     if (loop_number > 0 && params.config.only_one_perimeter_top && upper_slices == nullptr)
         loop_number = 0;
@@ -1441,7 +1444,7 @@ void PerimeterGenerator::process_classic(
     int        loop_number = params.config.perimeters + surface.extra_perimeters - 1;  // 0-indexed loops
 
     // SuperSlicer: set the topmost layer to be one perimeter
-    if (loop_number > 0 && params.config.only_one_perimeter_top && upper_slices == nullptr)
+    if ((params.layer_id == 0 && params.config.only_one_perimeter_first_layer) || (loop_number > 0 && params.config.only_one_perimeter_top && upper_slices == nullptr))
         loop_number = 0;
 
     ExPolygons last        = union_ex(surface.expolygon.simplify_p(params.scaled_resolution));

src/libslic3r/Preset.cpp

@@ -474,7 +474,7 @@ static std::vector<std::string> s_Preset_print_options {
     "perimeter_generator", "wall_transition_length", "wall_transition_filter_deviation", "wall_transition_angle",
     "wall_distribution_count", "min_feature_size", "min_bead_width",
     // SuperSlicer
-    "only_one_perimeter_top", "min_width_top_surface",
+    "only_one_perimeter_first_layer", "only_one_perimeter_top", "min_width_top_surface",
 };
 
 static std::vector<std::string> s_Preset_filament_options {

src/libslic3r/PrintConfig.cpp

@@ -566,6 +566,12 @@ void PrintConfigDef::init_fff_params()
     def->mode = comAdvanced;
     def->set_default_value(new ConfigOptionFloat(1));
 
+    def = this->add("only_one_perimeter_first_layer", coBool);
+    def->label = L("On First layer");
+    def->category = L("Layers and Perimeters");
+    def->tooltip = L("Use only one perimeter on first layer, to give more space to the top infill pattern.");
+    def->set_default_value(new ConfigOptionBool(false));
+
     def = this->add("only_one_perimeter_top", coBool);
     def->label = L("On top surfaces");
     def->category = L("Layers and Perimeters");

src/libslic3r/PrintConfig.hpp

@@ -663,6 +663,7 @@ PRINT_CONFIG_CLASS_DEFINE(
     ((ConfigOptionFloatOrPercent,       top_solid_infill_speed))
     ((ConfigOptionBool,                 wipe_into_infill))
     // SuperSlicer
+    ((ConfigOptionBool,                 only_one_perimeter_first_layer))
     ((ConfigOptionBool,                 only_one_perimeter_top))
     ((ConfigOptionFloatOrPercent,       min_width_top_surface))
 )

src/libslic3r/PrintObject.cpp

@@ -708,7 +708,8 @@ bool PrintObject::invalidate_state_by_config_options(
             // Brim is printed below supports, support invalidates brim and skirt.
             steps.emplace_back(posSupportMaterial);
         } else if (
-               opt_key == "only_one_perimeter_top") {
+               opt_key == "only_one_perimeter_first_layer"
+               || opt_key == "only_one_perimeter_top") {
             steps.emplace_back(posPerimeters);
         } else if (
                opt_key == "perimeters"

src/slic3r/GUI/ConfigManipulation.cpp

@@ -220,7 +220,8 @@ void ConfigManipulation::toggle_print_fff_options(DynamicPrintConfig* config)
     bool have_perimeters = config->opt_int("perimeters") > 0;
     for (auto el : { "extra_perimeters","extra_perimeters_on_overhangs", "thin_walls", "overhangs",
                     "seam_position","staggered_inner_seams", "external_perimeters_first", "external_perimeter_extrusion_width",
-                    "perimeter_speed", "small_perimeter_speed", "external_perimeter_speed", "enable_dynamic_overhang_speeds"})
+                    "perimeter_speed", "small_perimeter_speed", "external_perimeter_speed", "enable_dynamic_overhang_speeds",
+                    "only_one_perimeter_first_layer", "only_one_perimeter_top"})
         toggle_field(el, have_perimeters);
 
     for (size_t i = 0; i < 4; i++) {

src/slic3r/GUI/Tab.cpp

@@ -1474,6 +1474,7 @@ void TabPrint::build()
         optgroup = page->new_optgroup(L("Quality (slower slicing)"));
         line = { L("Only one perimeter"), "" };
         line.label_path = category_path + "only-one-perimeter-top-bottom";
+        line.append_option(optgroup->get_option("only_one_perimeter_first_layer"));
         line.append_option(optgroup->get_option("only_one_perimeter_top"));
         line.append_option(optgroup->get_option("min_width_top_surface"));
         optgroup->append_line(line);