added bottom layers option to GOO exporter

src/libslic3r/Format/GOO.cpp

@@ -38,6 +38,20 @@ static float constrained_map(float value, float min, float max, float out_min, f
     return out_min * (1 - t) + out_max * t;
 }
 
+static float generate_layer_exposure_time(
+    int current_layer, int bottom_layers, int faded_layers,
+    float initial_exposure_time, float exposure_time
+) {
+    if (current_layer <= bottom_layers) {
+        return initial_exposure_time;
+    } else {
+        return constrained_map(
+            current_layer - bottom_layers, 1, faded_layers + 1,
+            initial_exposure_time, exposure_time
+        );
+    }
+}
+
 static void write_thumbnail(
     size_t width, size_t height, const ThumbnailsList &thumbnails, uint16_t *buffer
 ) {
@@ -375,8 +389,8 @@ void GOOWriter::export_print(
         l_def.position_mm = hton<float>(
             mat.initial_layer_height.getFloat() + layer_height * (current_layer - 1)
         );
-        l_def.exposure_time_s = hton(constrained_map(
-            current_layer, 1, obj_stats.faded_layers + 1, //
+        l_def.exposure_time_s = hton(generate_layer_exposure_time(
+            current_layer, obj_stats.bottom_layers, obj_stats.faded_layers,
             mat.initial_exposure_time, mat.exposure_time
         ));
         l_def.off_time_s = 0;
@@ -431,4 +445,4 @@ ConfigSubstitutions GOOReader::read(
     return {};
 }
 
-} // namespace Slic3r
+} // namespace Slic3r

src/libslic3r/Preset.cpp

@@ -540,6 +540,7 @@ static std::vector<std::string> s_Preset_printer_options {
 static std::vector<std::string> s_Preset_sla_print_options {
     "layer_height",
     "faded_layers",
+    "bottom_layers",
     "supports_enable",
     "support_tree_type",
 

src/libslic3r/PrintConfig.cpp

@@ -4183,6 +4183,14 @@ void PrintConfigDef::init_sla_params()
     def->mode = comExpert;
     def->set_default_value(new ConfigOptionInt(10));
 
+    def = this->add("bottom_layers", coInt);
+    def->label = L("Bottom Layers");
+    def->tooltip = L("Number of layers the initial exposure time is repeated for.");
+    def->min = 1;
+    def->max = 20;
+    def->mode = comExpert;
+    def->set_default_value(new ConfigOptionInt(10));
+
     def = this->add("min_exposure_time", coFloat);
     def->label = L("Minimum exposure time");
     def->tooltip = L("Minimum exposure time");

src/libslic3r/PrintConfig.hpp

@@ -987,6 +987,8 @@ PRINT_CONFIG_CLASS_DEFINE(
 
     //Number of the layers needed for the exposure time fade [3;20]
     ((ConfigOptionInt,  faded_layers))/*= 10*/
+    //Number of layers the initial exposure time is repeated for [1;20]
+    ((ConfigOptionInt,  bottom_layers))/*= 10*/
 
     ((ConfigOptionFloat, slice_closing_radius))
     ((ConfigOptionEnum<SlicingMode>, slicing_mode))

src/slic3r/GUI/Tab.cpp

@@ -5878,6 +5878,7 @@ void TabSLAPrint::build()
     auto optgroup = page->new_optgroup(L("Layers"));
     optgroup->append_single_option_line("layer_height");
     optgroup->append_single_option_line("faded_layers");
+    optgroup->append_single_option_line("bottom_layers");
 
     page = add_options_page(L("Supports"), "support"/*"sla_supports"*/);