Ony one perimeter on first layer

src/libslic3r/PerimeterGenerator.cpp

@@ -1115,6 +1115,10 @@ 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
+
+    if (params.config.only_one_perimeter_first && params.layer_id == 0)
+        loop_number = 0;
+
     ExPolygons last        = offset_ex(surface.expolygon.simplify_p(params.scaled_resolution), - float(ext_perimeter_width / 2. - ext_perimeter_spacing / 2.));
     Polygons   last_p      = to_polygons(last);
 
@@ -1376,6 +1380,9 @@ void PerimeterGenerator::process_classic(
     // 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
+
+    if (params.config.only_one_perimeter_first && params.layer_id == 0)
+        loop_number = 0;
     ExPolygons last        = union_ex(surface.expolygon.simplify_p(params.scaled_resolution));
     ExPolygons gaps;
     if (loop_number >= 0) {

src/libslic3r/Preset.cpp

@@ -437,6 +437,7 @@ void Preset::set_visible_from_appconfig(const AppConfig &app_config)
 
 static std::vector<std::string> s_Preset_print_options {
     "layer_height", "first_layer_height", "perimeters", "spiral_vase", "slice_closing_radius", "slicing_mode",
+    "only_one_perimeter_first",
     "top_solid_layers", "top_solid_min_thickness", "bottom_solid_layers", "bottom_solid_min_thickness",
     "extra_perimeters", "extra_perimeters_on_overhangs", "avoid_crossing_curled_overhangs", "avoid_crossing_perimeters", "thin_walls", "overhangs",
     "seam_position","staggered_inner_seams", "external_perimeters_first", "fill_density", "fill_pattern", "top_fill_pattern", "bottom_fill_pattern",

src/libslic3r/PrintConfig.cpp

@@ -618,6 +618,12 @@ void PrintConfigDef::init_fff_params()
     def->mode = comAdvanced;
     def->set_default_value(new ConfigOptionFloat(1));
 
+    def = this->add("only_one_perimeter_first", coBool);
+    def->label = L("on first layer");
+    def->category = L("Layers and Perimeters");
+    def->tooltip = L("Print one perimeter on first layer to leave more space for infill. Could be usefull for small details and better look.");
+    def->set_default_value(new ConfigOptionBool(false));
+
     def = this->add("bridge_speed", coFloat);
     def->label = L("Bridges");
     def->category = L("Speed");

src/libslic3r/PrintConfig.hpp

@@ -666,6 +666,7 @@ PRINT_CONFIG_CLASS_DEFINE(
     ((ConfigOptionFloat,                top_solid_min_thickness))
     ((ConfigOptionFloatOrPercent,       top_solid_infill_speed))
     ((ConfigOptionBool,                 wipe_into_infill))
+    ((ConfigOptionBool,                 only_one_perimeter_first))
 )
 
 PRINT_CONFIG_CLASS_DEFINE(

src/libslic3r/PrintObject.cpp

@@ -714,6 +714,7 @@ bool PrintObject::invalidate_state_by_config_options(
             steps.emplace_back(posSupportMaterial);
         } else if (
                opt_key == "perimeters"
+            || opt_key == "only_one_perimeter_first"
             || opt_key == "extra_perimeters"
             || opt_key == "extra_perimeters_on_overhangs"
             || opt_key == "first_layer_extrusion_width"

src/slic3r/GUI/ConfigManipulation.cpp

@@ -241,7 +241,8 @@ void ConfigManipulation::toggle_print_fff_options(DynamicPrintConfig* config)
     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"
-                    "bridge_fan_internal_perimeter", "bridge_fan_external_perimeter"})
+                    "bridge_fan_internal_perimeter", "bridge_fan_external_perimeter",
+                    "only_one_perimeter_first"})
         toggle_field(el, have_perimeters);
 
     for (size_t i = 0; i < 4; i++) {

src/slic3r/GUI/Plater.cpp

@@ -2131,7 +2131,7 @@ Plater::priv::priv(Plater *q, MainFrame *main_frame)
         "extruder_colour", "filament_colour", "material_colour", "max_print_height", "printer_model", "printer_notes", "printer_technology",
         // These values are necessary to construct SlicingParameters by the Canvas3D variable layer height editor.
         "layer_height", "first_layer_height", "min_layer_height", "max_layer_height",
-        "brim_width", "perimeters", "perimeter_extruder", "fill_density", "infill_extruder", "top_solid_layers", 
+        "brim_width", "perimeters", "only_one_perimeter_first", "perimeter_extruder", "fill_density", "infill_extruder", "top_solid_layers", 
         "support_material", "support_material_extruder", "support_material_interface_extruder", 
         "support_material_contact_distance", "support_material_bottom_contact_distance", "raft_layers"
         }))

src/slic3r/GUI/Tab.cpp

@@ -1472,6 +1472,7 @@ void TabPrint::build()
 	    optgroup->append_line(line);
 
         optgroup = page->new_optgroup(L("Quality (slower slicing)"));
+        line.append_option(optgroup->get_option("only_one_perimeter_first"));
         optgroup->append_single_option_line("extra_perimeters", category_path + "extra-perimeters-if-needed");
         optgroup->append_single_option_line("extra_perimeters_on_overhangs", category_path + "extra-perimeters-on-overhangs");
         optgroup->append_single_option_line("avoid_crossing_curled_overhangs", category_path + "avoid-crossing-curled-overhangs");