Allow specifying print order within each layer (#3685)

* Allow reordering objects regardless of print seq

* Add option to control the layer print order

* Sort object by their order in object list instead of id

* Show print order when print order is the same as the object list

* Ensure the print order when print order is same as object list

* Update option name

---------

Co-authored-by: SoftFever <softfeverever@gmail.com>

src/libslic3r/GCode.cpp

@@ -1834,6 +1834,15 @@ static inline std::vector<const PrintInstance*> sort_object_instances_by_max_z(c
 //BBS: add sort logic for seq-print
 std::vector<const PrintInstance*> sort_object_instances_by_model_order(const Print& print, bool init_order)
 {
+    auto find_object_index = [](const Model& model, const ModelObject* obj) {
+        for (int index = 0; index < model.objects.size(); index++)
+        {
+            if (model.objects[index] == obj)
+                return index;
+        }
+        return -1;
+    };
+
     // Build up map from ModelInstance* to PrintInstance*
     std::vector<std::pair<const ModelInstance*, const PrintInstance*>> model_instance_to_print_instance;
     model_instance_to_print_instance.reserve(print.num_object_instances());
@@ -1841,10 +1850,16 @@ std::vector<const PrintInstance*> sort_object_instances_by_model_order(const Pri
         for (const PrintInstance &print_instance : print_object->instances())
         {
             if (init_order)
-                const_cast<ModelInstance*>(print_instance.model_instance)->arrange_order = print_instance.model_instance->id().id;
+                const_cast<ModelInstance*>(print_instance.model_instance)->arrange_order = find_object_index(print.model(), print_object->model_object());
             model_instance_to_print_instance.emplace_back(print_instance.model_instance, &print_instance);
         }
     std::sort(model_instance_to_print_instance.begin(), model_instance_to_print_instance.end(), [](auto &l, auto &r) { return l.first->arrange_order < r.first->arrange_order; });
+    if (init_order) {
+        // Re-assign the arrange_order so each instance has a unique order number
+        for (int k = 0; k < model_instance_to_print_instance.size(); k++) {
+            const_cast<ModelInstance*>(model_instance_to_print_instance[k].first)->arrange_order = k + 1;
+        }
+    }
 
     std::vector<const PrintInstance*> instances;
     instances.reserve(model_instance_to_print_instance.size());
@@ -2203,8 +2218,11 @@ void GCode::_do_export(Print& print, GCodeOutputStream &file, ThumbnailsGenerato
         // In non-sequential print, the printing extruders may have been modified by the extruder switches stored in Model::custom_gcode_per_print_z.
         // Therefore initialize the printing extruders from there.
         this->set_extruders(tool_ordering.all_extruders());
-        // Order object instances using a nearest neighbor search.
-        print_object_instances_ordering = chain_print_object_instances(print);
+        print_object_instances_ordering = 
+            // By default, order object instances using a nearest neighbor search.
+            print.config().print_order == PrintOrder::Default ? chain_print_object_instances(print)
+            // Otherwise same order as the object list
+            : sort_object_instances_by_model_order(print);
     }
     if (initial_extruder_id == (unsigned int)-1) {
         // Nothing to print!
@@ -3972,7 +3990,7 @@ LayerResult GCode::process_layer(
         std::vector<InstanceToPrint> instances_to_print;
         bool has_prime_tower = print.config().enable_prime_tower
             && print.extruders().size() > 1
-            && (print.config().print_sequence == PrintSequence::ByLayer
+            && ((print.config().print_sequence == PrintSequence::ByLayer && print.config().print_order == PrintOrder::Default)
                 || (print.config().print_sequence == PrintSequence::ByObject && print.objects().size() == 1));
         if (has_prime_tower) {
             int plate_idx = print.get_plate_index();

src/libslic3r/Preset.cpp

@@ -786,7 +786,7 @@ static std::vector<std::string> s_Preset_print_options {
     "independent_support_layer_height",
     "support_angle", "support_interface_top_layers", "support_interface_bottom_layers",
     "support_interface_pattern", "support_interface_spacing", "support_interface_loop_pattern",
-    "support_top_z_distance", "support_on_build_plate_only","support_critical_regions_only", "bridge_no_support", "thick_bridges", "thick_internal_bridges","dont_filter_internal_bridges", "max_bridge_length", "print_sequence", "support_remove_small_overhang",
+    "support_top_z_distance", "support_on_build_plate_only","support_critical_regions_only", "bridge_no_support", "thick_bridges", "thick_internal_bridges","dont_filter_internal_bridges", "max_bridge_length", "print_sequence", "print_order", "support_remove_small_overhang",
     "filename_format", "wall_filament", "support_bottom_z_distance",
     "sparse_infill_filament", "solid_infill_filament", "support_filament", "support_interface_filament","support_interface_not_for_body",
     "ooze_prevention", "standby_temperature_delta", "interface_shells", "line_width", "initial_layer_line_width",

src/libslic3r/Print.cpp

@@ -314,6 +314,7 @@ bool Print::invalidate_state_by_config_options(const ConfigOptionResolver & /* n
             //|| opt_key == "resolution"
             //BBS: when enable arc fitting, we must re-generate perimeter
             || opt_key == "enable_arc_fitting"
+            || opt_key == "print_order"
             || opt_key == "wall_sequence") {
             osteps.emplace_back(posPerimeters);
             osteps.emplace_back(posEstimateCurledExtrusions);

src/libslic3r/PrintConfig.cpp

@@ -195,6 +195,12 @@ static t_config_enum_values s_keys_map_PrintSequence {
 };
 CONFIG_OPTION_ENUM_DEFINE_STATIC_MAPS(PrintSequence)
 
+static t_config_enum_values s_keys_map_PrintOrder{
+    { "default",     int(PrintOrder::Default) },
+    { "as_obj_list", int(PrintOrder::AsObjectList)},
+};
+CONFIG_OPTION_ENUM_DEFINE_STATIC_MAPS(PrintOrder)
+
 static t_config_enum_values s_keys_map_SlicingMode {
     { "regular",        int(SlicingMode::Regular) },
     { "even_odd",       int(SlicingMode::EvenOdd) },
@@ -1171,6 +1177,17 @@ void PrintConfigDef::init_fff_params()
     def->mode = comSimple;
     def->set_default_value(new ConfigOptionEnum<PrintSequence>(PrintSequence::ByLayer));
 
+    def = this->add("print_order", coEnum);
+    def->label = L("Layer order");
+    def->tooltip = L("Print order within a single layer");
+    def->enum_keys_map = &ConfigOptionEnum<PrintOrder>::get_enum_values();
+    def->enum_values.push_back("default");
+    def->enum_values.push_back("as_obj_list");
+    def->enum_labels.push_back(L("Default"));
+    def->enum_labels.push_back(L("As object list"));
+    def->mode = comAdvanced;
+    def->set_default_value(new ConfigOptionEnum<PrintOrder>(PrintOrder::Default));
+
     def = this->add("slow_down_for_layer_cooling", coBools);
     def->label = L("Slow printing down for better layer cooling");
     def->tooltip = L("Enable this option to slow printing speed down to make the final layer time not shorter than "

src/libslic3r/PrintConfig.hpp

@@ -106,6 +106,13 @@ enum class PrintSequence {
     Count,
 };
 
+enum class PrintOrder
+{
+    Default,
+    AsObjectList,
+    Count,
+};
+
 enum class SlicingMode
 {
     // Regular, applying ClipperLib::pftNonZero rule when creating ExPolygons.
@@ -1101,6 +1108,7 @@ PRINT_CONFIG_CLASS_DERIVED_DEFINE(
     ((ConfigOptionInts,               overhang_fan_speed))
     ((ConfigOptionEnumsGeneric,       overhang_fan_threshold))
     ((ConfigOptionEnum<PrintSequence>,print_sequence))
+    ((ConfigOptionEnum<PrintOrder>,   print_order))
     ((ConfigOptionInts,               first_layer_print_sequence))
     ((ConfigOptionBools,              slow_down_for_layer_cooling))
     ((ConfigOptionInts,               close_fan_the_first_x_layers))