.

src/libslic3r/ExtrusionEntity.hpp

@@ -339,21 +339,32 @@ public:
     ExtrusionPaths paths;
 
     ExtrusionMultiPath() {}
-    ExtrusionMultiPath(const ExtrusionMultiPath &rhs) : paths(rhs.paths), m_can_reverse(rhs.m_can_reverse) {}
-    ExtrusionMultiPath(ExtrusionMultiPath &&rhs) : paths(std::move(rhs.paths)), m_can_reverse(rhs.m_can_reverse) {}
-    ExtrusionMultiPath(const ExtrusionPaths &paths) : paths(paths) {}
-    ExtrusionMultiPath(const ExtrusionPath &path) {this->paths.push_back(path); m_can_reverse = path.can_reverse(); }
+    ExtrusionMultiPath(const ExtrusionMultiPath &rhs) : ExtrusionEntity(rhs), paths(rhs.paths), m_can_reverse(rhs.m_can_reverse) {}
+    ExtrusionMultiPath(ExtrusionMultiPath &&rhs) : ExtrusionEntity(rhs), paths(std::move(rhs.paths)), m_can_reverse(rhs.m_can_reverse) {}
+    ExtrusionMultiPath(const ExtrusionPaths &paths) : paths(paths)
+    {
+        if (!paths.empty())
+            this->inset_idx = paths.front().inset_idx;
+    }
+    ExtrusionMultiPath(const ExtrusionPath &path)
+    {
+        this->paths.push_back(path);
+        this->inset_idx = path.inset_idx;
+        m_can_reverse = path.can_reverse();
+    }
 
     ExtrusionMultiPath &operator=(const ExtrusionMultiPath &rhs)
     {
-        this->paths   = rhs.paths;
-        m_can_reverse = rhs.m_can_reverse;
+        this->paths     = rhs.paths;
+        this->inset_idx = rhs.inset_idx;
+        m_can_reverse   = rhs.m_can_reverse;
         return *this;
     }
     ExtrusionMultiPath &operator=(ExtrusionMultiPath &&rhs)
     {
-        this->paths   = std::move(rhs.paths);
-        m_can_reverse = rhs.m_can_reverse;
+        this->paths     = std::move(rhs.paths);
+        this->inset_idx = rhs.inset_idx;
+        m_can_reverse   = rhs.m_can_reverse;
         return *this;
     }
 
@@ -404,12 +415,27 @@ public:
     ExtrusionPaths paths;
 
     ExtrusionLoop(ExtrusionLoopRole role = elrDefault) : m_loop_role(role) {}
-    ExtrusionLoop(const ExtrusionPaths &paths, ExtrusionLoopRole role = elrDefault) : paths(paths), m_loop_role(role) {}
-    ExtrusionLoop(ExtrusionPaths &&paths, ExtrusionLoopRole role = elrDefault) : paths(std::move(paths)), m_loop_role(role) {}
+    ExtrusionLoop(const ExtrusionPaths &paths, ExtrusionLoopRole role = elrDefault) : paths(paths), m_loop_role(role)
+    {
+        if (!paths.empty())
+            this->inset_idx = paths.front().inset_idx;
+    }
+    ExtrusionLoop(ExtrusionPaths &&paths, ExtrusionLoopRole role = elrDefault) : paths(std::move(paths)), m_loop_role(role)
+    {
+        if (!this->paths.empty())
+            this->inset_idx = this->paths.front().inset_idx;
+    }
     ExtrusionLoop(const ExtrusionPath &path, ExtrusionLoopRole role = elrDefault) : m_loop_role(role)
-        { this->paths.push_back(path); }
+    {
+        this->paths.push_back(path);
+        this->inset_idx = path.inset_idx;
+    }
     ExtrusionLoop(const ExtrusionPath &&path, ExtrusionLoopRole role = elrDefault) : m_loop_role(role)
-        { this->paths.emplace_back(std::move(path)); }
+    {
+        this->paths.emplace_back(std::move(path));
+        if (!this->paths.empty())
+            this->inset_idx = this->paths.front().inset_idx;
+    }
     bool is_loop() const override{ return true; }
     bool can_reverse() const override { return false; }
 	ExtrusionEntity* clone() const override{ return new ExtrusionLoop (*this); }

src/libslic3r/GCode.cpp

@@ -4770,15 +4770,32 @@ LayerResult GCode::process_layer(const Print& print,
     auto configured_filament_id_1based = [&layer_tools](const GCode::ObjectByExtruder::Island::Region::Type entity_type,
                                                         const ExtrusionEntityCollection&                    entities,
                                                         const PrintRegion&                                  region) -> unsigned int {
+        auto raw_sparse_infill_filament_id_1based = [&layer_tools, &region]() -> unsigned int {
+            const PrintRegionConfig &config = region.config();
+            if (!config.enable_infill_filament_override.value)
+                return unsigned(config.wall_filament.value);
+            if (layer_tools.object_layer_count <= 0)
+                return unsigned(config.sparse_infill_filament.value);
+
+            const int first_layers = std::max(0, config.infill_filament_use_base_first_layers.value);
+            const int last_layers  = std::max(0, config.infill_filament_use_base_last_layers.value);
+            return (layer_tools.layer_index < first_layers ||
+                    layer_tools.layer_index >= layer_tools.object_layer_count - last_layers)
+                ? unsigned(config.wall_filament.value)
+                : unsigned(config.sparse_infill_filament.value);
+        };
+
         if (entity_type == GCode::ObjectByExtruder::Island::Region::INFILL) {
+            if (layer_tools.extruder_override != 0)
+                return layer_tools.extruder_override;
             const ExtrusionRole role = entities.entities.empty() ? erNone : entities.entities.front()->role();
             if (role == erSolidInfill && std::abs(region.config().sparse_infill_density.value - 100.) < EPSILON)
-                return layer_tools.sparse_infill_filament(region) + 1;
+                return raw_sparse_infill_filament_id_1based();
             if (is_solid_infill(role))
-                return layer_tools.solid_infill_filament(region) + 1;
-            return layer_tools.sparse_infill_filament(region) + 1;
+                return unsigned(region.config().solid_infill_filament.value);
+            return raw_sparse_infill_filament_id_1based();
         }
-        return layer_tools.wall_filament(region) + 1;
+        return layer_tools.extruder_override == 0 ? unsigned(region.config().wall_filament.value) : layer_tools.extruder_override;
     };
 
     auto configured_extruder_id = [&layer_tools](const GCode::ObjectByExtruder::Island::Region::Type entity_type,
@@ -5318,28 +5335,39 @@ LayerResult GCode::process_layer(const Print& print,
                                                                                            layer_tools.num_physical,
                                                                                            layer_tools.layer_index,
                                                                                            split_by_extruder,
-                                                                                           bucket_count) &&
-                                    bucket_count >= 2) {
-                                    for (size_t extruder_idx = 0; extruder_idx < split_by_extruder.size(); ++extruder_idx) {
-                                        std::unique_ptr<ExtrusionEntityCollection>& split_collection = split_by_extruder[extruder_idx];
-                                        if (!split_collection || split_collection->entities.empty())
-                                            continue;
-                                        const ExtrusionEntityCollection* split_ptr = split_collection.get();
-                                        local_z_clipped_collections.emplace_back(std::move(split_collection));
-                                        std::vector<ObjectByExtruder::Island>& islands =
-                                            object_islands_by_extruder(by_extruder, unsigned(extruder_idx), layer_to_print_idx, layers.size(), n_slices + 1);
-                                        for (size_t i = 0; i <= n_slices; ++i) {
-                                            const bool   last       = i == n_slices;
-                                            const size_t island_idx = last ? n_slices : slices_test_order[i];
-                                            if (last || point_inside_surface(island_idx, split_ptr->first_point())) {
-                                                if (islands[island_idx].by_region.empty())
-                                                    islands[island_idx].by_region.assign(print.num_print_regions(), ObjectByExtruder::Island::Region());
-                                                islands[island_idx].by_region[region.print_region_id()].append(entity_type, split_ptr, nullptr);
+                                                                                           bucket_count)) {
+                                    if (bucket_count >= 2) {
+                                        for (size_t extruder_idx = 0; extruder_idx < split_by_extruder.size(); ++extruder_idx) {
+                                            std::unique_ptr<ExtrusionEntityCollection>& split_collection = split_by_extruder[extruder_idx];
+                                            if (!split_collection || split_collection->entities.empty())
+                                                continue;
+                                            const ExtrusionEntityCollection* split_ptr = split_collection.get();
+                                            local_z_clipped_collections.emplace_back(std::move(split_collection));
+                                            std::vector<ObjectByExtruder::Island>& islands =
+                                                object_islands_by_extruder(by_extruder, unsigned(extruder_idx), layer_to_print_idx, layers.size(), n_slices + 1);
+                                            for (size_t i = 0; i <= n_slices; ++i) {
+                                                const bool   last       = i == n_slices;
+                                                const size_t island_idx = last ? n_slices : slices_test_order[i];
+                                                if (last || point_inside_surface(island_idx, split_ptr->first_point())) {
+                                                    if (islands[island_idx].by_region.empty())
+                                                        islands[island_idx].by_region.assign(print.num_print_regions(), ObjectByExtruder::Island::Region());
+                                                    islands[island_idx].by_region[region.print_region_id()].append(entity_type, split_ptr, nullptr);
+                                                    break;
+                                                }
+                                            }
+                                        }
+                                        continue;
+                                    }
+                                    if (bucket_count == 1) {
+                                        for (size_t extruder_idx = 0; extruder_idx < split_by_extruder.size(); ++extruder_idx) {
+                                            const std::unique_ptr<ExtrusionEntityCollection>& split_collection = split_by_extruder[extruder_idx];
+                                            if (split_collection && !split_collection->entities.empty()) {
+                                                // by_extruder keys and LayerTools runtime extruder IDs are zero-based here.
+                                                correct_extruder_id = int(extruder_idx);
                                                 break;
                                             }
                                         }
                                     }
-                                    continue;
                                 }
                             }
                         }

src/libslic3r/GCode/ToolOrdering.cpp

@@ -120,6 +120,24 @@ unsigned int grouped_manual_pattern_mixed_filament_id_for_layer(const LayerTools
     return 0;
 }
 
+unsigned int grouped_manual_pattern_infill_filament_1based(const LayerTools&  layer_tools,
+                                                           const PrintRegion& region,
+                                                           unsigned int       configured_filament_id_1based)
+{
+    const unsigned int grouped_id =
+        grouped_manual_pattern_mixed_filament_id_for_layer(layer_tools, configured_filament_id_1based);
+    if (grouped_id == 0)
+        return 0;
+
+    const int innermost_perimeter_index = std::max(0, region.config().wall_loops.value - 1);
+    return layer_tools.mixed_mgr->resolve_perimeter(grouped_id,
+                                                    layer_tools.num_physical,
+                                                    layer_tools.layer_index,
+                                                    innermost_perimeter_index,
+                                                    float(layer_tools.print_z),
+                                                    float(layer_tools.layer_height));
+}
+
 void remove_duplicates_preserve_order(std::vector<unsigned int> &values)
 {
     std::vector<unsigned int> ordered;
@@ -279,14 +297,16 @@ unsigned int LayerTools::sparse_infill_filament(const PrintRegion &region) const
 {
 	assert(region.config().wall_filament.value > 0);
 	unsigned int id = (this->extruder_override == 0) ? sparse_infill_filament_id_1based(*this, region) : this->extruder_override;
-	return resolve_mixed_1based(id) - 1;
+    const unsigned int grouped = grouped_manual_pattern_infill_filament_1based(*this, region, id);
+	return ((grouped != 0) ? grouped : resolve_mixed_1based(id)) - 1;
 }
 
 unsigned int LayerTools::solid_infill_filament(const PrintRegion &region) const
 {
 	assert(region.config().solid_infill_filament.value > 0);
 	unsigned int id = (this->extruder_override == 0) ? region.config().solid_infill_filament.value : this->extruder_override;
-	return resolve_mixed_1based(id) - 1;
+    const unsigned int grouped = grouped_manual_pattern_infill_filament_1based(*this, region, id);
+	return ((grouped != 0) ? grouped : resolve_mixed_1based(id)) - 1;
 }
 
 // Returns a zero based extruder this eec should be printed with, according to PrintRegion config or extruder_override if overriden.
@@ -295,19 +315,13 @@ unsigned int LayerTools::extruder(const ExtrusionEntityCollection &extrusions, c
 	assert(region.config().wall_filament.value > 0);
 	assert(region.config().sparse_infill_filament.value > 0);
 	assert(region.config().solid_infill_filament.value > 0);
-	// 1 based extruder ID.
-    unsigned int extruder = 1;
-    if (this->extruder_override == 0) {
-        if (extrusions.has_infill()) {
-            const ExtrusionRole role = extrusions.entities.empty() ? erNone : extrusions.entities.front()->role();
-            extruder = infill_filament_id_1based(*this, region, role);
-        } else
-            extruder = region.config().wall_filament.value;
-    } else
-        extruder = this->extruder_override;
-
-    extruder = resolve_mixed_1based(extruder);
-    return (extruder == 0) ? 0 : extruder - 1;
+    if (extrusions.has_infill()) {
+        const ExtrusionRole role = extrusions.entities.empty() ? erNone : extrusions.entities.front()->role();
+        if (internal_solid_infill_uses_sparse_filament(region, role))
+            return sparse_infill_filament(region);
+        return is_solid_infill(role) ? solid_infill_filament(region) : sparse_infill_filament(region);
+    }
+    return wall_filament(region);
 }
 
 static double calc_max_layer_height(const PrintConfig &config, double max_object_layer_height)
@@ -718,8 +732,9 @@ void ToolOrdering::collect_extruders(const PrintObject &object, const std::vecto
                                                                      layerCount,
                                                                      float(layer->print_z),
                                                                      float(layer->height));
-                        if (ordered.size() >= 2) {
-                            layer_tools.preserve_extruder_order = true;
+                        if (!ordered.empty()) {
+                            if (ordered.size() >= 2)
+                                layer_tools.preserve_extruder_order = true;
                             for (unsigned int extruder_id : ordered) {
                                 layer_tools.extruders.emplace_back(extruder_id);
                                 if (layerCount == 0 &&
@@ -764,10 +779,7 @@ void ToolOrdering::collect_extruders(const PrintObject &object, const std::vecto
             if (something_nonoverriddable || !m_print_config_ptr) {
             	if (extruder_override == 0) {
 	                if (has_solid_infill)
-	                    layer_tools.extruders.emplace_back(resolve_mixed(region.config().solid_infill_filament,
-                                                                         layerCount,
-                                                                         float(layer->print_z),
-                                                                         float(layer->height)));
+	                    layer_tools.extruders.emplace_back(layer_tools.solid_infill_filament(region) + 1);
 	                if (has_sparse_infill)
 	                    layer_tools.extruders.emplace_back(layer_tools.sparse_infill_filament(region) + 1);
             	} else if (has_solid_infill || has_sparse_infill)

src/libslic3r/LayerRegion.cpp

@@ -46,6 +46,39 @@ unsigned int effective_layer_filament_id(const Layer &layer, unsigned int filame
                                                                                 float(layer.height));
 }
 
+unsigned int effective_infill_filament_id(const Layer &layer, const PrintRegionConfig &config, unsigned int filament_id)
+{
+    const unsigned int effective = effective_layer_filament_id(layer, filament_id);
+    if (effective != filament_id || filament_id == 0)
+        return effective;
+
+    const PrintObject *object = layer.object();
+    const Print       *print  = object ? object->print() : nullptr;
+    if (print == nullptr)
+        return filament_id;
+
+    const size_t num_physical = print->config().filament_diameter.size();
+    if (num_physical == 0)
+        return filament_id;
+
+    const MixedFilamentManager &mixed_mgr = print->mixed_filament_manager();
+    const MixedFilament *mixed_row = mixed_mgr.mixed_filament_from_id(filament_id, num_physical);
+    if (mixed_row == nullptr)
+        return filament_id;
+
+    const std::string normalized_pattern = MixedFilamentManager::normalize_manual_pattern(mixed_row->manual_pattern);
+    if (normalized_pattern.find(',') == std::string::npos)
+        return filament_id;
+
+    const int innermost_perimeter_index = std::max(0, config.wall_loops.value - 1);
+    return mixed_mgr.resolve_perimeter(filament_id,
+                                       num_physical,
+                                       int(layer.id()),
+                                       innermost_perimeter_index,
+                                       float(layer.print_z),
+                                       float(layer.height));
+}
+
 bool use_base_infill_filament(const PrintRegionConfig &config, int layer_index, int layer_count)
 {
     if (!config.enable_infill_filament_override.value)
@@ -71,7 +104,9 @@ unsigned int LayerRegion::extruder(FlowRole role) const
     else
         filament_id = this->region().extruder(role);
 
-    return effective_layer_filament_id(*m_layer, filament_id);
+    return (role == frInfill || role == frSolidInfill) ?
+        effective_infill_filament_id(*m_layer, config, filament_id) :
+        effective_layer_filament_id(*m_layer, filament_id);
 }
 
 Flow LayerRegion::flow(FlowRole role) const

src/libslic3r/PerimeterGenerator.cpp

@@ -570,6 +570,10 @@ static ExtrusionEntityCollection traverse_extrusions(const PerimeterGenerator& p
 
         // Append paths to collection.
         if (!paths.empty()) {
+            const int inset_idx = int(extrusion->inset_idx);
+            for (ExtrusionPath &path : paths)
+                path.inset_idx = inset_idx;
+
             if (extrusion->is_closed) {
                 ExtrusionLoop extrusion_loop(std::move(paths), pg_extrusion.is_contour ? elrDefault : elrHole);
                 extrusion_loop.make_counter_clockwise();
@@ -581,6 +585,7 @@ static ExtrusionEntityCollection traverse_extrusions(const PerimeterGenerator& p
                 }
                 assert(extrusion_loop.paths.front().first_point() == extrusion_loop.paths.back().last_point());
 
+                extrusion_loop.inset_idx = inset_idx;
                 extrusion_coll.append(std::move(extrusion_loop));
             }
             else {
@@ -593,11 +598,13 @@ static ExtrusionEntityCollection traverse_extrusions(const PerimeterGenerator& p
                 }
                 ExtrusionMultiPath multi_path;
                 multi_path.paths.emplace_back(std::move(paths.front()));
+                multi_path.inset_idx = inset_idx;
 
                 for (auto it_path = std::next(paths.begin()); it_path != paths.end(); ++it_path) {
                     if (multi_path.paths.back().last_point() != it_path->first_point()) {
                         extrusion_coll.append(ExtrusionMultiPath(std::move(multi_path)));
                         multi_path = ExtrusionMultiPath();
+                        multi_path.inset_idx = inset_idx;
                     }
                     multi_path.paths.emplace_back(std::move(*it_path));
                 }

src/slic3r/GUI/Plater.cpp

@@ -4566,6 +4566,7 @@ struct MixedFilamentPreviewSettings
     double preferred_a_height { 0.0 };
     double preferred_b_height { 0.0 };
     bool   local_z_mode { false };
+    size_t wall_loops { 1 };
 };
 
 // Inline editor panel for configuring a single mixed filament
@@ -4634,7 +4635,11 @@ private:
     // Helper functions (copied from update_mixed_filament_panel)
     static std::vector<unsigned int> decode_gradient_ids(const std::string &s);
     static std::string encode_gradient_ids(const std::vector<unsigned int> &ids);
-    static std::vector<unsigned int> decode_manual_pattern_ids(const std::string &pattern, unsigned int a, unsigned int b);
+    static std::vector<unsigned int> decode_manual_pattern_ids(const std::string &pattern,
+                                                               unsigned int       a,
+                                                               unsigned int       b,
+                                                               size_t             num_physical,
+                                                               size_t             wall_loops = 0);
     static std::vector<int> decode_gradient_weights(const std::string &s, size_t n);
     static std::vector<int> normalize_gradient_weights(const std::vector<int> &w, size_t n);
     static std::string encode_gradient_weights(const std::vector<int> &w);
@@ -4784,6 +4789,100 @@ private:
 };
 
 // Implementation of MixedFilamentConfigPanel helper functions
+static std::vector<std::string> split_manual_pattern_preview_groups(const std::string &pattern)
+{
+    std::vector<std::string> groups;
+    if (pattern.empty())
+        return groups;
+
+    std::string current;
+    for (const char c : pattern) {
+        if (c == ',') {
+            if (!current.empty()) {
+                groups.emplace_back(std::move(current));
+                current.clear();
+            }
+            continue;
+        }
+        current.push_back(c);
+    }
+    if (!current.empty())
+        groups.emplace_back(std::move(current));
+    return groups;
+}
+
+static unsigned int decode_manual_pattern_preview_token(char token, unsigned int component_a, unsigned int component_b, size_t num_physical)
+{
+    unsigned int extruder_id = 0;
+    if (token == '1')
+        extruder_id = component_a;
+    else if (token == '2')
+        extruder_id = component_b;
+    else if (token >= '3' && token <= '9')
+        extruder_id = unsigned(token - '0');
+
+    return (extruder_id >= 1 && extruder_id <= num_physical) ? extruder_id : 0;
+}
+
+static std::vector<unsigned int> build_grouped_manual_pattern_preview_sequence(const std::string &pattern,
+                                                                               unsigned int       component_a,
+                                                                               unsigned int       component_b,
+                                                                               size_t             num_physical,
+                                                                               size_t             wall_loops)
+{
+    std::vector<unsigned int> sequence;
+    if (num_physical == 0)
+        return sequence;
+
+    const std::string normalized = MixedFilamentManager::normalize_manual_pattern(pattern);
+    if (normalized.empty())
+        return sequence;
+
+    const std::vector<std::string> groups = split_manual_pattern_preview_groups(normalized);
+    if (groups.empty())
+        return sequence;
+
+    if (groups.size() == 1) {
+        sequence.reserve(normalized.size());
+        for (const char token : normalized) {
+            const unsigned int extruder_id =
+                decode_manual_pattern_preview_token(token, component_a, component_b, num_physical);
+            if (extruder_id != 0)
+                sequence.emplace_back(extruder_id);
+        }
+        return sequence;
+    }
+
+    constexpr size_t k_max_preview_cycle = 48;
+    size_t cycle = 1;
+    for (const std::string &group : groups) {
+        if (group.empty())
+            continue;
+        cycle = std::lcm(cycle, group.size());
+        if (cycle >= k_max_preview_cycle) {
+            cycle = k_max_preview_cycle;
+            break;
+        }
+    }
+
+    const size_t preview_wall_loops = std::max<size_t>(1, wall_loops == 0 ? groups.size() : wall_loops);
+    sequence.reserve(preview_wall_loops * cycle);
+    for (size_t layer_idx = 0; layer_idx < cycle; ++layer_idx) {
+        for (size_t wall_idx = 0; wall_idx < preview_wall_loops; ++wall_idx) {
+            const std::string &group = groups[std::min(wall_idx, groups.size() - 1)];
+            if (group.empty())
+                continue;
+            const char token = group[layer_idx % group.size()];
+            const unsigned int extruder_id =
+                decode_manual_pattern_preview_token(token, component_a, component_b, num_physical);
+            if (extruder_id != 0)
+                sequence.emplace_back(extruder_id);
+        }
+    }
+
+    return sequence;
+}
+
 std::vector<unsigned int> MixedFilamentConfigPanel::decode_gradient_ids(const std::string &s)
 {
     std::vector<unsigned int> ids;
@@ -4816,15 +4915,13 @@ std::string MixedFilamentConfigPanel::encode_gradient_ids(const std::vector<unsi
     return out;
 }
 
-std::vector<unsigned int> MixedFilamentConfigPanel::decode_manual_pattern_ids(const std::string &pattern, unsigned int a, unsigned int b)
+std::vector<unsigned int> MixedFilamentConfigPanel::decode_manual_pattern_ids(const std::string &pattern,
+                                                                              unsigned int       a,
+                                                                              unsigned int       b,
+                                                                              size_t             num_physical,
+                                                                              size_t             wall_loops)
 {
-    std::vector<unsigned int> seq;
-    for (char c : pattern) {
-        if (c == '1' || c == 'A' || c == 'a') seq.emplace_back(a);
-        else if (c == '2' || c == 'B' || c == 'b') seq.emplace_back(b);
-        else if (c >= '3' && c <= '9') seq.emplace_back(unsigned(c - '0'));
-    }
-    return seq;
+    return build_grouped_manual_pattern_preview_sequence(pattern, a, b, num_physical, wall_loops);
 }
 
 std::vector<int> MixedFilamentConfigPanel::decode_gradient_weights(const std::string &s, size_t n)
@@ -5947,7 +6044,11 @@ void MixedFilamentConfigPanel::build_ui()
             m_mf.pointillism_all_filaments = false;
             m_mf.gradient_component_ids.clear();
             m_mf.gradient_component_weights.clear();
-            preview_sequence = decode_manual_pattern_ids(m_mf.manual_pattern, m_mf.component_a, m_mf.component_b);
+            preview_sequence = decode_manual_pattern_ids(m_mf.manual_pattern,
+                                                         m_mf.component_a,
+                                                         m_mf.component_b,
+                                                         m_num_physical,
+                                                         m_preview_settings.wall_loops);
         } else {
             std::vector<unsigned int> selected_ids;
             selected_ids.reserve(4);
@@ -6254,7 +6355,11 @@ void MixedFilamentConfigPanel::update_preview()
 
     std::vector<unsigned int> initial_sequence;
     if (pattern_row_mode) {
-        initial_sequence = decode_manual_pattern_ids(normalized_pattern, m_mf.component_a, m_mf.component_b);
+        initial_sequence = decode_manual_pattern_ids(normalized_pattern,
+                                                     m_mf.component_a,
+                                                     m_mf.component_b,
+                                                     m_num_physical,
+                                                     m_preview_settings.wall_loops);
     } else {
         std::vector<unsigned int> initial_gradient_ids = simple_mode ? std::vector<unsigned int>() : decode_gradient_ids(m_mf.gradient_component_ids);
         if (initial_gradient_ids.size() >= 3)
@@ -6707,24 +6812,11 @@ void Sidebar::update_mixed_filament_panel(bool sync_manager)
             sequence = filtered_ids;
         return sequence;
     };
-    auto decode_manual_pattern_ids = [num_physical](const std::string &pattern, unsigned int component_a, unsigned int component_b) {
-        std::vector<unsigned int> sequence;
-        if (num_physical == 0)
-            return sequence;
-        const std::string normalized = MixedFilamentManager::normalize_manual_pattern(pattern);
-        sequence.reserve(normalized.size());
-        for (const char token : normalized) {
-            unsigned int extruder_id = 0;
-            if (token == '1')
-                extruder_id = component_a;
-            else if (token == '2')
-                extruder_id = component_b;
-            else if (token >= '3' && token <= '9')
-                extruder_id = unsigned(token - '0');
-            if (extruder_id >= 1 && extruder_id <= num_physical)
-                sequence.emplace_back(extruder_id);
-        }
-        return sequence;
+    auto decode_manual_pattern_ids = [num_physical](const std::string &pattern,
+                                                    unsigned int       component_a,
+                                                    unsigned int       component_b,
+                                                    size_t             wall_loops) {
+        return build_grouped_manual_pattern_preview_sequence(pattern, component_a, component_b, num_physical, wall_loops);
     };
     const bool height_weighted_mode = get_mixed_mode(false);
     int   gradient_mode = height_weighted_mode ? 1 : 0;
@@ -6736,6 +6828,9 @@ void Sidebar::update_mixed_filament_panel(bool sync_manager)
     if (print_cfg && print_cfg->has("layer_height"))
         nominal_layer_height = float(print_cfg->opt_float("layer_height"));
     nominal_layer_height = std::max(0.01f, nominal_layer_height);
+    size_t wall_loops = 1;
+    if (print_cfg && print_cfg->has("wall_loops"))
+        wall_loops = std::max<size_t>(1, size_t(std::max(1, print_cfg->opt_int("wall_loops"))));
     const bool local_z_mode = get_mixed_bool("dithering_local_z_mode", false);
     float pointillism_pixel_size = std::max(0.f, get_mixed_float("mixed_filament_pointillism_pixel_size", 0.f));
     float pointillism_line_gap   = std::max(0.f, get_mixed_float("mixed_filament_pointillism_line_gap", 0.f));
@@ -6748,7 +6843,8 @@ void Sidebar::update_mixed_filament_panel(bool sync_manager)
         upper_bound,
         preferred_local_z_a,
         preferred_local_z_b,
-        local_z_mode
+        local_z_mode,
+        wall_loops
     };
     auto summarize_sequence = [num_physical](const std::vector<unsigned int> &sequence) {
         if (sequence.empty() || num_physical == 0)
@@ -6814,7 +6910,10 @@ void Sidebar::update_mixed_filament_panel(bool sync_manager)
                                          build_weighted_multi_sequence, preview_settings](const MixedFilament &entry) {
         const std::string normalized_pattern = MixedFilamentManager::normalize_manual_pattern(entry.manual_pattern);
         if (!normalized_pattern.empty())
-            return decode_manual_pattern_ids(normalized_pattern, entry.component_a, entry.component_b);
+            return decode_manual_pattern_ids(normalized_pattern,
+                                             entry.component_a,
+                                             entry.component_b,
+                                             preview_settings.wall_loops);
 
         const bool simple_mode = entry.distribution_mode == int(MixedFilament::Simple);
         if (!simple_mode) {

tests/libslic3r/test_mixed_filament.cpp

@@ -2,6 +2,8 @@
 
 #include "libslic3r/ExtrusionEntity.hpp"
 #include "libslic3r/PresetBundle.hpp"
+#include "libslic3r/Print.hpp"
+#include "libslic3r/GCode/ToolOrdering.hpp"
 
 #include <sstream>
 #include <vector>
@@ -221,6 +223,119 @@ TEST_CASE("Mixed filament perimeter resolver uses grouped manual patterns by ins
     CHECK(ordered_layer1[1] == 1);
 }
 
+TEST_CASE("Grouped manual perimeter patterns keep grouped resolution on collapsed single-tool layers", "[MixedFilament]")
+{
+    const std::vector<std::string> colors = {"#00FFFF", "#FF00FF"};
+
+    MixedFilamentManager mgr;
+    mgr.add_custom_filament(1, 2, 50, colors);
+    REQUIRE(mgr.mixed_filaments().size() == 1);
+
+    MixedFilament &row = mgr.mixed_filaments().front();
+    row.manual_pattern = MixedFilamentManager::normalize_manual_pattern("2,12");
+    REQUIRE(row.manual_pattern == "2,12");
+
+    const unsigned int mixed_filament_id = 3;
+
+    // The flattened row cadence resolves this layer to component A, but both
+    // perimeter groups collapse onto physical filament 2. G-code generation
+    // and tool ordering must keep using the grouped perimeter result here.
+    CHECK(mgr.resolve(mixed_filament_id, 2, 1) == 1);
+
+    const std::vector<unsigned int> ordered_layer1 = mgr.ordered_perimeter_extruders(mixed_filament_id, 2, 1);
+    REQUIRE(ordered_layer1.size() == 1);
+    CHECK(ordered_layer1.front() == 2);
+
+    CHECK(mgr.resolve_perimeter(mixed_filament_id, 2, 1, 0) == 2);
+    CHECK(mgr.resolve_perimeter(mixed_filament_id, 2, 1, 1) == 2);
+    CHECK(mgr.resolve_perimeter(mixed_filament_id, 2, 1, 2) == 2);
+}
+
+TEST_CASE("Grouped manual perimeter patterns resolve overlapping singleton inner groups", "[MixedFilament]")
+{
+    const std::vector<std::string> colors = {"#00FFFF", "#FF00FF"};
+
+    MixedFilamentManager mgr;
+    mgr.add_custom_filament(1, 2, 50, colors);
+    REQUIRE(mgr.mixed_filaments().size() == 1);
+
+    MixedFilament &row = mgr.mixed_filaments().front();
+    row.manual_pattern = MixedFilamentManager::normalize_manual_pattern("12,1");
+    REQUIRE(row.manual_pattern == "12,1");
+
+    const unsigned int mixed_filament_id = 3;
+
+    const std::vector<unsigned int> ordered_layer0 = mgr.ordered_perimeter_extruders(mixed_filament_id, 2, 0);
+    const std::vector<unsigned int> ordered_layer1 = mgr.ordered_perimeter_extruders(mixed_filament_id, 2, 1);
+
+    REQUIRE(ordered_layer0.size() == 1);
+    CHECK(ordered_layer0.front() == 1);
+    REQUIRE(ordered_layer1.size() == 2);
+    CHECK(ordered_layer1[0] == 2);
+    CHECK(ordered_layer1[1] == 1);
+
+    CHECK(mgr.resolve_perimeter(mixed_filament_id, 2, 0, 0) == 1);
+    CHECK(mgr.resolve_perimeter(mixed_filament_id, 2, 0, 1) == 1);
+    CHECK(mgr.resolve_perimeter(mixed_filament_id, 2, 1, 0) == 2);
+    CHECK(mgr.resolve_perimeter(mixed_filament_id, 2, 1, 1) == 1);
+    CHECK(mgr.resolve_perimeter(mixed_filament_id, 2, 2, 0) == 1);
+    CHECK(mgr.resolve_perimeter(mixed_filament_id, 2, 2, 1) == 1);
+}
+
+TEST_CASE("Grouped manual wall patterns make infill follow the innermost perimeter tool", "[MixedFilament]")
+{
+    const std::vector<std::string> colors = {"#00FFFF", "#FF00FF"};
+
+    MixedFilamentManager mgr;
+    mgr.add_custom_filament(1, 2, 50, colors);
+    REQUIRE(mgr.mixed_filaments().size() == 1);
+
+    MixedFilament &row = mgr.mixed_filaments().front();
+    row.manual_pattern = MixedFilamentManager::normalize_manual_pattern("12,1");
+    REQUIRE(row.manual_pattern == "12,1");
+
+    PrintRegionConfig region_config = static_cast<const PrintRegionConfig &>(FullPrintConfig::defaults());
+    region_config.wall_filament.value                  = 3;
+    region_config.wall_loops.value                     = 2;
+    region_config.enable_infill_filament_override.value = false;
+    region_config.sparse_infill_density.value          = 15.;
+    region_config.sparse_infill_filament.value         = 2;
+    region_config.solid_infill_filament.value          = 3;
+
+    PrintRegion region(region_config);
+
+    LayerTools layer0(0.2);
+    layer0.layer_index       = 0;
+    layer0.object_layer_count = 6;
+    layer0.layer_height      = 0.2;
+    layer0.mixed_mgr         = &mgr;
+    layer0.num_physical      = 2;
+
+    LayerTools layer1(0.4);
+    layer1.layer_index       = 1;
+    layer1.object_layer_count = 6;
+    layer1.layer_height      = 0.2;
+    layer1.mixed_mgr         = &mgr;
+    layer1.num_physical      = 2;
+
+    CHECK(layer0.wall_filament(region) == 0);
+    CHECK(layer1.wall_filament(region) == 1);
+    CHECK(layer0.sparse_infill_filament(region) == 0);
+    CHECK(layer1.sparse_infill_filament(region) == 0);
+    CHECK(layer0.solid_infill_filament(region) == 0);
+    CHECK(layer1.solid_infill_filament(region) == 0);
+
+    region_config.enable_infill_filament_override.value = true;
+    region_config.sparse_infill_filament.value          = 2;
+    region_config.solid_infill_filament.value           = 2;
+    PrintRegion overridden_region(region_config);
+
+    CHECK(layer0.sparse_infill_filament(overridden_region) == 1);
+    CHECK(layer1.sparse_infill_filament(overridden_region) == 1);
+    CHECK(layer0.solid_infill_filament(overridden_region) == 1);
+    CHECK(layer1.solid_infill_filament(overridden_region) == 1);
+}
+
 TEST_CASE("Mixed filament painted-region resolver collapses ordinary mixed rows to the active physical extruder", "[MixedFilament]")
 {
     const std::vector<std::string> colors = {"#FF0000", "#00FF00"};
@@ -269,3 +384,26 @@ TEST_CASE("ExtrusionPath copies preserve inset index", "[MixedFilament]")
     assigned = src;
     CHECK(assigned.inset_idx == 3);
 }
+
+TEST_CASE("Extrusion loop and multipath entities preserve inset index", "[MixedFilament]")
+{
+    ExtrusionPath src(erPerimeter);
+    src.inset_idx = 2;
+
+    ExtrusionMultiPath multi_from_path(src);
+    CHECK(multi_from_path.inset_idx == 2);
+
+    ExtrusionMultiPath multi_copy(multi_from_path);
+    CHECK(multi_copy.inset_idx == 2);
+
+    ExtrusionMultiPath multi_assigned;
+    multi_assigned.inset_idx = 0;
+    multi_assigned = multi_from_path;
+    CHECK(multi_assigned.inset_idx == 2);
+
+    ExtrusionLoop loop_from_path(src);
+    CHECK(loop_from_path.inset_idx == 2);
+
+    ExtrusionLoop loop_copy(loop_from_path);
+    CHECK(loop_copy.inset_idx == 2);
+}