Added a config option to not print sparse layers on the wipe tower

src/libslic3r/GCode.cpp

@@ -313,8 +313,11 @@ std::string WipeTowerIntegration::append_tcr(GCode &gcodegen, const WipeTower::T
     double current_z = gcodegen.writer().get_position().z();
     if (z == -1.) // in case no specific z was provided, print at current_z pos
         z = current_z;
-    if (! is_approx(z, current_z))
+    if (! is_approx(z, current_z)) {
+        gcode += gcodegen.writer().retract();
         gcode += gcodegen.writer().travel_to_z(z, "Travel down to the last wipe tower layer.");
+        gcode += gcodegen.writer().unretract();
+    }
 
 
     // Process the end filament gcode.
@@ -526,13 +529,18 @@ std::string WipeTowerIntegration::tool_change(GCode &gcodegen, int extruder_id,
                 throw std::runtime_error("Wipe tower generation failed, possibly due to empty first layer.");
 
 
-            double wipe_tower_z = m_last_wipe_tower_print_z;
-            bool is_sparse_layer = (m_brim_done && m_tool_changes[m_layer_idx].size() == 1 && m_tool_changes[m_layer_idx].front().initial_tool == m_tool_changes[m_layer_idx].front().new_tool);
+            // Calculate where the wipe tower layer will be printed. -1 means that print z will not change,
+            // resulting in a wipe tower with sparse layers.
+            double wipe_tower_z = -1;
+            bool ignore_sparse = false;
+            if (gcodegen.config().wipe_tower_no_sparse_layers.value) {
+                wipe_tower_z = m_last_wipe_tower_print_z;
+                ignore_sparse = (m_brim_done && m_tool_changes[m_layer_idx].size() == 1 && m_tool_changes[m_layer_idx].front().initial_tool == m_tool_changes[m_layer_idx].front().new_tool);
+                if (m_tool_change_idx == 0 && ! ignore_sparse)
+                   wipe_tower_z = m_last_wipe_tower_print_z + m_tool_changes[m_layer_idx].front().layer_height;
+            }
 
-            if (m_tool_change_idx == 0 && ! is_sparse_layer)
-                wipe_tower_z = m_last_wipe_tower_print_z + m_tool_changes[m_layer_idx].front().layer_height;
-
-            if (! is_sparse_layer) {
+            if (! ignore_sparse) {
                 gcode += append_tcr(gcodegen, m_tool_changes[m_layer_idx][m_tool_change_idx++], extruder_id, wipe_tower_z);
                 m_last_wipe_tower_print_z = wipe_tower_z;
             }

src/libslic3r/Print.cpp

@@ -143,6 +143,7 @@ bool Print::invalidate_state_by_config_options(const std::vector<t_config_option
         "use_volumetric_e",
         "variable_layer_height",
         "wipe",
+        "wipe_tower_no_sparse_layers",
         "wipe_tower_x",
         "wipe_tower_y",
         "wipe_tower_rotation_angle"

src/libslic3r/PrintConfig.cpp

@@ -1825,6 +1825,14 @@ void PrintConfigDef::init_fff_params()
     def->mode = comAdvanced;
     def->set_default_value(new ConfigOptionBool(true));
 
+    def = this->add("wipe_tower_no_sparse_layers", coBool);
+    def->label = L("No sparse layers");
+    def->tooltip = L("If enabled, the wipe tower will not be printed on layers with no toolchanges. "
+                     "On layers with a toolchange, extruder will travel downward to print the wipe tower. "
+                     "User is responsible for ensuring there is no collision with the print.");
+    def->mode = comAdvanced;
+    def->set_default_value(new ConfigOptionBool(false));
+
     def = this->add("support_material", coBool);
     def->label = L("Generate support material");
     def->category = L("Support material");

src/libslic3r/PrintConfig.hpp

@@ -648,6 +648,7 @@ public:
     ConfigOptionStrings             start_filament_gcode;
     ConfigOptionBool                single_extruder_multi_material;
     ConfigOptionBool                single_extruder_multi_material_priming;
+    ConfigOptionBool                wipe_tower_no_sparse_layers;
     ConfigOptionString              toolchange_gcode;
     ConfigOptionFloat               travel_speed;
     ConfigOptionBool                use_firmware_retraction;
@@ -718,6 +719,7 @@ protected:
         OPT_PTR(retract_speed);
         OPT_PTR(single_extruder_multi_material);
         OPT_PTR(single_extruder_multi_material_priming);
+        OPT_PTR(wipe_tower_no_sparse_layers);
         OPT_PTR(start_gcode);
         OPT_PTR(start_filament_gcode);
         OPT_PTR(toolchange_gcode);

src/slic3r/GUI/Preset.cpp

@@ -385,7 +385,7 @@ const std::vector<std::string>& Preset::print_options()
         "top_infill_extrusion_width", "support_material_extrusion_width", "infill_overlap", "bridge_flow_ratio", "clip_multipart_objects",
         "elefant_foot_compensation", "xy_size_compensation", "threads", "resolution", "wipe_tower", "wipe_tower_x", "wipe_tower_y",
         "wipe_tower_width", "wipe_tower_rotation_angle", "wipe_tower_bridging", "single_extruder_multi_material_priming",
-        "compatible_printers", "compatible_printers_condition", "inherits"
+        "wipe_tower_no_sparse_layers", "compatible_printers", "compatible_printers_condition", "inherits"
     };
     return s_opts;
 }

src/slic3r/GUI/Tab.cpp

@@ -1170,6 +1170,7 @@ void TabPrint::build()
         optgroup->append_single_option_line("wipe_tower_width");
         optgroup->append_single_option_line("wipe_tower_rotation_angle");
         optgroup->append_single_option_line("wipe_tower_bridging");
+        optgroup->append_single_option_line("wipe_tower_no_sparse_layers");
         optgroup->append_single_option_line("single_extruder_multi_material_priming");
 
         optgroup = page->new_optgroup(_(L("Advanced")));