1) Storing the physical_printer_settings_id into the 3MF, AMF, GCode.

2) Activating the physical_printer_settings_id when loading from 3MF, AMF, GCode.
   The physical printer is only activated if it references the printer_settings_id
   loaded from the same file.
3) When loading the presets from 3MF, AMF, GCode, the "external" profiles
   are no more created for profiles which differ from the local profiles
   the loaded profiles reference. Instead, the referenced profile is activated
   and modified with the loaded preset. If the referenced profile does not
   exist, but the profile refers to a system profile with the "inherits"
   fileds, the system profile is loaded and modified instead.
   This works for all profiles with the exception of multi-extruder
   printer with multiple filament profiles modified. In that case
   the first modified filament profile will be loaded as modified,
   while the other modified profiles will be loaded as "external".

This should fix
Physical printer + 3mf file, wrong preset used to generate gcode #5178
and possibly
https://github.com/prusa3d/PrusaSlicer/issues/5272

src/libslic3r/Preset.cpp

@@ -731,8 +731,9 @@ static bool profile_print_params_same(const DynamicPrintConfig &cfg_old, const D
 
 // Load a preset from an already parsed config file, insert it into the sorted sequence of presets
 // and select it, losing previous modifications.
-// In case
+// Only a single profile could be edited at at the same time, which introduces complexity when loading
-Preset& PresetCollection::load_external_preset(
+// filament profiles for multi-extruder printers.
+std::pair<Preset*, bool> PresetCollection::load_external_preset(
     // Path to the profile source file (a G-code, an AMF or 3MF file, a config file)
     const std::string           &path,
     // Name of the profile, derived from the source file name.
@@ -742,11 +743,20 @@ Preset& PresetCollection::load_external_preset(
     // Config to initialize the preset from.
     const DynamicPrintConfig    &config,
     // Select the preset after loading?
-    bool                         select)
+    LoadAndSelect                select)
 {
     // Load the preset over a default preset, so that the missing fields are filled in from the default preset.
     DynamicPrintConfig cfg(this->default_preset_for(config).config);
     cfg.apply_only(config, cfg.keys(), true);
+    std::string                 &inherits = Preset::inherits(cfg);
+    if (select == LoadAndSelect::Never) {
+        // Some filament profile has been selected and modified already.
+        // Check whether this profile is equal to the modified edited profile.
+        const Preset &edited = this->get_edited_preset();
+        if ((edited.name == original_name || edited.name == inherits) && profile_print_params_same(edited.config, cfg))
+            // Just point to that already selected and edited profile.
+            return std::make_pair(&(*this->find_preset_internal(edited.name)), false);
+    }
     // Is there a preset already loaded with the name stored inside the config?
     std::deque<Preset>::iterator it       = this->find_preset_internal(original_name);
     bool                         found    = it != m_presets.end() && it->name == original_name;
@@ -757,19 +767,40 @@ Preset& PresetCollection::load_external_preset(
     }
     if (found && profile_print_params_same(it->config, cfg)) {
         // The preset exists and it matches the values stored inside config.
-        if (select)
+        if (select == LoadAndSelect::Always)
             this->select_preset(it - m_presets.begin());
-        return *it;
+        return std::make_pair(&(*it), false);
     }
+    if (! found && select != LoadAndSelect::Never && ! inherits.empty()) {
+        // Try to use a system profile as a base to select the system profile
+        // and override its settings with the loaded ones.
+        assert(it == m_presets.end());
+        it    = this->find_preset_internal(inherits);
+        found = it != m_presets.end() && it->name == inherits;
+        if (found && profile_print_params_same(it->config, cfg)) {
+            // The system preset exists and it matches the values stored inside config.
+            if (select == LoadAndSelect::Always)
+                this->select_preset(it - m_presets.begin());
+            return std::make_pair(&(*it), false);
+        }
+    }
+    if (found) {
+        if (select != LoadAndSelect::Never) {
+            // Select the existing preset and override it with new values, so that
+            // the differences will be shown in the preset editor against the referenced profile.
+            this->select_preset(it - m_presets.begin());
+            this->get_edited_preset().config.apply(config);
+            this->update_dirty();
+            assert(this->get_edited_preset().is_dirty);
+            return std::make_pair(&(*it), this->get_edited_preset().is_dirty);
+        }
+        if (inherits.empty()) {
             // Update the "inherits" field.
-    std::string &inherits = Preset::inherits(cfg);
-    if (found && inherits.empty()) {
             // There is a profile with the same name already loaded. Should we update the "inherits" field?
-        if (it->vendor == nullptr)
+            inherits = it->vendor ? it->name : it->inherits();
-            inherits = it->inherits();
-        else
-            inherits = it->name;
         }
+    }
+
     // The external preset does not match an internal preset, load the external preset.
     std::string new_name;
     for (size_t idx = 0;; ++ idx) {
@@ -790,19 +821,19 @@ Preset& PresetCollection::load_external_preset(
             break;
         if (profile_print_params_same(it->config, cfg)) {
             // The preset exists and it matches the values stored inside config.
-            if (select)
+            if (select == LoadAndSelect::Always)
                 this->select_preset(it - m_presets.begin());
-            return *it;
+            return std::make_pair(&(*it), false);
         }
         // Form another profile name.
     }
     // Insert a new profile.
-    Preset &preset = this->load_preset(path, new_name, std::move(cfg), select);
+    Preset &preset = this->load_preset(path, new_name, std::move(cfg), select == LoadAndSelect::Always);
     preset.is_external = true;
     if (&this->get_selected_preset() == &preset)
         this->get_edited_preset().is_external = true;
 
-    return preset;
+    return std::make_pair(&preset, false);
 }
 
 Preset& PresetCollection::load_preset(const std::string &path, const std::string &name, DynamicPrintConfig &&config, bool select)

src/libslic3r/Preset.hpp

@@ -287,7 +287,18 @@ public:
     Preset&         load_preset(const std::string &path, const std::string &name, const DynamicPrintConfig &config, bool select = true);
     Preset&         load_preset(const std::string &path, const std::string &name, DynamicPrintConfig &&config, bool select = true);
 
-    Preset&         load_external_preset(
+    // Returns a loaded preset, returns true if an existing preset was selected AND modified from config.
+    // In that case the successive filament loaded for a multi material printer should not be modified, but
+    // an external preset should be created instead.
+    enum class LoadAndSelect {
+        // Never select
+        Never,
+        // Always select
+        Always,
+        // Select a profile only if it was modified.
+        OnlyIfModified,
+    };
+    std::pair<Preset*, bool> load_external_preset(
         // Path to the profile source file (a G-code, an AMF or 3MF file, a config file)
         const std::string           &path,
         // Name of the profile, derived from the source file name.
@@ -297,7 +308,7 @@ public:
         // Config to initialize the preset from.
         const DynamicPrintConfig    &config,
         // Select the preset after loading?
-        bool                         select = true);
+        LoadAndSelect                select = LoadAndSelect::Always);
 
     // Save the preset under a new name. If the name is different from the old one,
     // a new preset is stored into the list of presets.

src/libslic3r/PresetBundle.cpp

@@ -49,7 +49,7 @@ PresetBundle::PresetBundle() :
     // initialized based on PrintConfigDef(), but to empty values (zeros, empty vectors, empty strings).
     //
     // "compatible_printers", "compatible_printers_condition", "inherits",
-    // "print_settings_id", "filament_settings_id", "printer_settings_id",
+    // "print_settings_id", "filament_settings_id", "printer_settings_id", "printer_settings_id"
     // "printer_vendor", "printer_model", "printer_variant", "default_print_profile", "default_filament_profile"
 
     // Create the ID config keys, as they are not part of the Static print config classes.
@@ -586,6 +586,7 @@ DynamicPrintConfig PresetBundle::full_fff_config() const
     out.option<ConfigOptionString >("print_settings_id",    true)->value  = this->prints.get_selected_preset_name();
     out.option<ConfigOptionStrings>("filament_settings_id", true)->values = this->filament_presets;
     out.option<ConfigOptionString >("printer_settings_id",  true)->value  = this->printers.get_selected_preset_name();
+    out.option<ConfigOptionString >("physical_printer_settings_id", true)->value = this->physical_printers.get_selected_printer_name();
 
     // Serialize the collected "compatible_printers_condition" and "inherits" fields.
     // There will be 1 + num_exturders fields for "inherits" and 2 + num_extruders for "compatible_printers_condition" stored.
@@ -637,6 +638,7 @@ DynamicPrintConfig PresetBundle::full_sla_config() const
     out.option<ConfigOptionString >("sla_print_settings_id",    true)->value  = this->sla_prints.get_selected_preset_name();
     out.option<ConfigOptionString >("sla_material_settings_id", true)->value  = this->sla_materials.get_selected_preset_name();
     out.option<ConfigOptionString >("printer_settings_id",      true)->value  = this->printers.get_selected_preset_name();
+    out.option<ConfigOptionString >("physical_printer_settings_id", true)->value = this->physical_printers.get_selected_printer_name();
 
     // Serialize the collected "compatible_printers_condition" and "inherits" fields.
     // There will be 1 + num_exturders fields for "inherits" and 2 + num_extruders for "compatible_printers_condition" stored.
@@ -712,6 +714,7 @@ void PresetBundle::load_config_file(const std::string &path)
 }
 
 // Load a config file from a boost property_tree. This is a private method called from load_config_file.
+// is_external == false on if called from ConfigWizard
 void PresetBundle::load_config_file_config(const std::string &name_or_path, bool is_external, DynamicPrintConfig &&config)
 {
     PrinterTechnology printer_technology = Preset::printer_technology(config);
@@ -798,14 +801,17 @@ void PresetBundle::load_config_file_config(const std::string &name_or_path, bool
 			compatible_prints_condition   = compatible_prints_condition_values.front();
 			Preset                *loaded = nullptr;
 			if (is_external) {
-				loaded = &this->filaments.load_external_preset(name_or_path, name, old_filament_profile_names->values.front(), config);
+				auto [aloaded, modified] = this->filaments.load_external_preset(name_or_path, name, old_filament_profile_names->values.front(), config);
+                loaded = aloaded;
 			} else {
-				loaded = &this->filaments.load_preset(this->filaments.path_from_name(name), name, config);
+                // called from Config Wizard.
+				loaded= &this->filaments.load_preset(this->filaments.path_from_name(name), name, config);
 				loaded->save();
 			}
             this->filament_presets.clear();
 			this->filament_presets.emplace_back(loaded->name);
         } else {
+            assert(is_external);
             // Split the filament presets, load each of them separately.
             std::vector<DynamicPrintConfig> configs(num_extruders, this->filaments.default_preset().config);
             // loop through options and scatter them into configs.
@@ -826,6 +832,7 @@ void PresetBundle::load_config_file_config(const std::string &name_or_path, bool
             // To avoid incorrect selection of the first filament preset (means a value of Preset->m_idx_selected) 
             // in a case when next added preset take a place of previosly selected preset,
             // we should add presets from last to first
+            bool any_modified = false;
             for (int i = (int)configs.size()-1; i >= 0; i--) {
                 DynamicPrintConfig &cfg = configs[i];
                 // Split the "compatible_printers_condition" and "inherits" from the cummulative vectors to separate filament presets.
@@ -833,24 +840,15 @@ void PresetBundle::load_config_file_config(const std::string &name_or_path, bool
                 cfg.opt_string("compatible_prints_condition",   true) = compatible_prints_condition_values[i];
                 cfg.opt_string("inherits", true)                      = inherits_values[i + 1];
                 // Load all filament presets, but only select the first one in the preset dialog.
-                Preset *loaded = nullptr;
+                auto [loaded, modified] = this->filaments.load_external_preset(name_or_path, name,
-                if (is_external)
-                    loaded = &this->filaments.load_external_preset(name_or_path, name,
                     (i < int(old_filament_profile_names->values.size())) ? old_filament_profile_names->values[i] : "",
-                        std::move(cfg), i == 0);
+                    std::move(cfg), 
-                else {
+                    i == 0 ? 
-                    // Used by the config wizard when creating a custom setup.
+                        PresetCollection::LoadAndSelect::Always : 
-                    // Therefore this block should only be called for a single extruder.
+                    any_modified ?
-                    char suffix[64];
+                        PresetCollection::LoadAndSelect::Never :
-                    if (i == 0)
+                        PresetCollection::LoadAndSelect::OnlyIfModified);
-                        suffix[0] = 0;
+                any_modified |= modified;
-                    else
-                        sprintf(suffix, "%d", (int)i);
-                    std::string new_name = name + suffix;
-                    loaded = &this->filaments.load_preset(this->filaments.path_from_name(new_name),
-                        new_name, std::move(cfg), i == 0);
-                    loaded->save();
-                }
                 this->filament_presets[i] = loaded->name;
             }
         }
@@ -864,10 +862,23 @@ void PresetBundle::load_config_file_config(const std::string &name_or_path, bool
         load_preset(this->sla_materials, 1, "sla_material_settings_id");
         load_preset(this->printers,      2, "printer_settings_id");
         break;
-    default: break;
+    default:
+        break;
     }
 
 	this->update_compatible(PresetSelectCompatibleType::Never);
+
+    const std::string &physical_printer = config.option<ConfigOptionString>("physical_printer_settings_id", true)->value;
+    if (this->printers.get_edited_preset().is_external || physical_printer.empty()) {
+        this->physical_printers.unselect_printer();
+    } else {
+        // Activate the physical printer profile if possible.
+        PhysicalPrinter *pp = this->physical_printers.find_printer(physical_printer, true);
+        if (pp != nullptr && std::find(pp->preset_names.begin(), pp->preset_names.end(), this->printers.get_edited_preset().name) != pp->preset_names.end())
+            this->physical_printers.select_printer(*pp);
+        else
+            this->physical_printers.unselect_printer();
+    }
 }
 
 // Load the active configuration of a config bundle from a boost property_tree. This is a private method called from load_config_file.

src/libslic3r/PresetBundle.hpp

@@ -70,7 +70,7 @@ public:
 
     // Load user configuration and store it into the user profiles.
     // This method is called by the configuration wizard.
-    void                        load_config(const std::string &name, DynamicPrintConfig config)
+    void                        load_config_from_wizard(const std::string &name, DynamicPrintConfig config)
         { this->load_config_file_config(name, false, std::move(config)); }
 
     // Load configuration that comes from a model file containing configuration, such as 3MF et al.

src/libslic3r/Print.cpp

@@ -599,6 +599,7 @@ Print::ApplyStatus Print::apply(const Model &model, DynamicPrintConfig new_full_
 	new_full_config.option("print_settings_id",            true);
 	new_full_config.option("filament_settings_id",         true);
 	new_full_config.option("printer_settings_id",          true);
+    new_full_config.option("physical_printer_settings_id", true);
     new_full_config.normalize_fdm();
 
     // Find modified keys of the various configs. Resolve overrides extruder retract values by filament profiles.
@@ -630,6 +631,7 @@ Print::ApplyStatus Print::apply(const Model &model, DynamicPrintConfig new_full_
 		m_placeholder_parser.set("print_preset",              new_full_config.option("print_settings_id")->clone());
 		m_placeholder_parser.set("filament_preset",           new_full_config.option("filament_settings_id")->clone());
 		m_placeholder_parser.set("printer_preset",            new_full_config.option("printer_settings_id")->clone());
+        m_placeholder_parser.set("physical_printer_preset",   new_full_config.option("physical_printer_settings_id")->clone());
 		// We want the filament overrides to be applied over their respective extruder parameters by the PlaceholderParser.
 		// see "Placeholders do not respect filament overrides." GH issue #3649
 		m_placeholder_parser.apply_config(filament_overrides);

src/libslic3r/PrintConfig.cpp

@@ -1680,6 +1680,10 @@ void PrintConfigDef::init_fff_params()
     def->set_default_value(new ConfigOptionString(""));
     def->cli = ConfigOptionDef::nocli;
 
+    def = this->add("physical_printer_settings_id", coString);
+    def->set_default_value(new ConfigOptionString(""));
+    def->cli = ConfigOptionDef::nocli;
+
     def = this->add("raft_layers", coInt);
     def->label = L("Raft layers");
     def->category = L("Support material");

src/libslic3r/SLAPrint.cpp

@@ -196,6 +196,7 @@ SLAPrint::ApplyStatus SLAPrint::apply(const Model &model, DynamicPrintConfig con
     config.option("sla_print_settings_id",        true);
     config.option("sla_material_settings_id",     true);
     config.option("printer_settings_id",          true);
+    config.option("physical_printer_settings_id", true);
     // Collect changes to print config.
     t_config_option_keys print_diff    = m_print_config.diff(config);
     t_config_option_keys printer_diff  = m_printer_config.diff(config);
@@ -231,6 +232,7 @@ SLAPrint::ApplyStatus SLAPrint::apply(const Model &model, DynamicPrintConfig con
         m_placeholder_parser.set("print_preset",            config.option("sla_print_settings_id")->clone());
         m_placeholder_parser.set("material_preset",         config.option("sla_material_settings_id")->clone());
         m_placeholder_parser.set("printer_preset",          config.option("printer_settings_id")->clone());
+        m_placeholder_parser.set("physical_printer_preset", config.option("physical_printer_settings_id")->clone());
     }
 
     // It is also safe to change m_config now after this->invalidate_state_by_config_options() call.

src/slic3r/GUI/ConfigWizard.cpp

@@ -2457,7 +2457,7 @@ void ConfigWizard::priv::apply_config(AppConfig *app_config, PresetBundle *prese
         page_temps->apply_custom_config(*custom_config);
 
         const std::string profile_name = page_custom->profile_name();
-        preset_bundle->load_config(profile_name, *custom_config);
+        preset_bundle->load_config_from_wizard(profile_name, *custom_config);
     }
 
     // Update the selections from the compatibilty.