Merge main + clean up code + fix missing include

src/libslic3r/Format/AssimpImport.cpp

@@ -0,0 +1,327 @@
+#include "AssimpImport.hpp"
+
+#include "../TexturePainting.hpp"
+#include "ResourcePathUtils.hpp"
+
+#include <assimp/Importer.hpp>
+#include <assimp/config.h>
+#include <assimp/material.h>
+#include <assimp/postprocess.h>
+#include <assimp/scene.h>
+
+#include <boost/algorithm/string/predicate.hpp>
+#include <boost/filesystem.hpp>
+#include <boost/log/trivial.hpp>
+#include <boost/nowide/fstream.hpp>
+
+#include <array>
+#include <cstdint>
+#include <limits>
+#include <sstream>
+#include <string>
+#include <vector>
+
+namespace Slic3r {
+namespace {
+
+void clear_textured_mesh(TexturedMesh& out)
+{
+    out.vertices.clear();
+    out.indices.clear();
+    out.uvs.clear();
+    out.uv_coords.clear();
+    out.uv_indices.clear();
+    out.textures.clear();
+    out.material_ids.clear();
+    out.material_texture_map.clear();
+    out.material_colors.clear();
+}
+
+void set_error_message(std::string* error_message, const std::string& message)
+{
+    if (error_message)
+        *error_message = message;
+}
+
+bool is_fbx_path(const std::string& path)
+{
+    return boost::algorithm::iends_with(path, ".fbx");
+}
+
+bool should_flip_uvs(const std::string& path)
+{
+    return boost::algorithm::iends_with(path, ".fbx") ||
+           boost::algorithm::iends_with(path, ".glb");
+}
+
+unsigned int assimp_import_flags(const std::string& path)
+{
+    unsigned int flags = aiProcess_Triangulate
+                       | aiProcess_GenNormals
+                       | aiProcess_PreTransformVertices
+                       | aiProcess_SortByPType;
+    if (should_flip_uvs(path))
+        flags |= aiProcess_FlipUVs;
+    return flags;
+}
+
+void configure_importer(Assimp::Importer& importer, const std::string& path, unsigned int flags)
+{
+    importer.SetPropertyInteger(AI_CONFIG_PP_SBP_REMOVE,
+        aiPrimitiveType_POINT | aiPrimitiveType_LINE);
+
+    if (flags & aiProcess_PreTransformVertices)
+        importer.SetPropertyBool(AI_CONFIG_PP_PTV_KEEP_HIERARCHY, true);
+
+    if (is_fbx_path(path)) {
+        importer.SetPropertyBool(AI_CONFIG_IMPORT_FBX_READ_ALL_GEOMETRY_LAYERS, true);
+        importer.SetPropertyBool(AI_CONFIG_IMPORT_FBX_READ_MATERIALS, true);
+        importer.SetPropertyBool(AI_CONFIG_IMPORT_FBX_READ_TEXTURES, true);
+        importer.SetPropertyBool(AI_CONFIG_IMPORT_FBX_READ_ANIMATIONS, false);
+        importer.SetPropertyBool(AI_CONFIG_IMPORT_FBX_READ_LIGHTS, false);
+        importer.SetPropertyBool(AI_CONFIG_IMPORT_FBX_READ_CAMERAS, false);
+    }
+}
+
+bool read_external_texture_file(const boost::filesystem::path& path, TextureImage& out)
+{
+    boost::nowide::ifstream file(path.string(), std::ios::binary | std::ios::ate);
+    if (!file.is_open())
+        return false;
+
+    const std::streamoff size = file.tellg();
+    if (size <= 0)
+        return false;
+    if (static_cast<uintmax_t>(size) > static_cast<uintmax_t>(std::numeric_limits<size_t>::max()))
+        return false;
+
+    file.seekg(0);
+    out.width = -1;
+    out.height = -1;
+    out.channels = 0;
+    out.data.resize(static_cast<size_t>(size));
+    file.read(reinterpret_cast<char*>(out.data.data()), size);
+    if (!file && !file.eof()) {
+        out.data.clear();
+        return false;
+    }
+    return true;
+}
+
+bool read_embedded_texture(const aiTexture& texture, TextureImage& out)
+{
+    out.data.clear();
+    if (texture.mHeight == 0) {
+        if (texture.mWidth == 0)
+            return false;
+        out.width = -1;
+        out.height = -1;
+        out.channels = 0;
+        out.data.assign(
+            reinterpret_cast<const unsigned char*>(texture.pcData),
+            reinterpret_cast<const unsigned char*>(texture.pcData) + texture.mWidth);
+        return !out.data.empty();
+    }
+
+    if (texture.mWidth == 0 || texture.mHeight == 0)
+        return false;
+    if (texture.mWidth > static_cast<unsigned int>(std::numeric_limits<int>::max()) ||
+        texture.mHeight > static_cast<unsigned int>(std::numeric_limits<int>::max())) {
+        return false;
+    }
+    const size_t width = static_cast<size_t>(texture.mWidth);
+    const size_t height = static_cast<size_t>(texture.mHeight);
+    if (width > std::numeric_limits<size_t>::max() / height ||
+        width * height > std::numeric_limits<size_t>::max() / 4) {
+        return false;
+    }
+
+    out.width = static_cast<int>(texture.mWidth);
+    out.height = static_cast<int>(texture.mHeight);
+    out.channels = 4;
+    const size_t pixel_count = width * height;
+    out.data.resize(pixel_count * 4);
+    for (size_t i = 0; i < pixel_count; ++i) {
+        const aiTexel& texel = texture.pcData[i];
+        out.data[i * 4 + 0] = texel.r;
+        out.data[i * 4 + 1] = texel.g;
+        out.data[i * 4 + 2] = texel.b;
+        out.data[i * 4 + 3] = texel.a;
+    }
+    return !out.data.empty();
+}
+
+bool get_material_texture(const aiMaterial& material, aiString& texture_path)
+{
+    if (material.GetTextureCount(aiTextureType_DIFFUSE) > 0 &&
+        material.GetTexture(aiTextureType_DIFFUSE, 0, &texture_path) == AI_SUCCESS) {
+        return true;
+    }
+
+    if (material.GetTextureCount(aiTextureType_BASE_COLOR) > 0 &&
+        material.GetTexture(aiTextureType_BASE_COLOR, 0, &texture_path) == AI_SUCCESS) {
+        return true;
+    }
+
+    return false;
+}
+
+std::array<float, 4> get_material_color(const aiMaterial& material)
+{
+    aiColor4D color(1.f, 1.f, 1.f, 1.f);
+    if (material.Get(AI_MATKEY_BASE_COLOR, color) == AI_SUCCESS)
+        return {color.r, color.g, color.b, color.a};
+    if (material.Get(AI_MATKEY_COLOR_DIFFUSE, color) == AI_SUCCESS)
+        return {color.r, color.g, color.b, color.a};
+    return {1.f, 1.f, 1.f, 1.f};
+}
+
+bool collect_mesh(const aiMesh& mesh, size_t& vertex_offset, TexturedMesh& out, std::string& error)
+{
+    if (mesh.mNumVertices > static_cast<size_t>(std::numeric_limits<int>::max()) - vertex_offset) {
+        error = "Assimp mesh has too many vertices for TexturedMesh indices";
+        return false;
+    }
+
+    for (unsigned int i = 0; i < mesh.mNumVertices; ++i) {
+        const aiVector3D& v = mesh.mVertices[i];
+        out.vertices.push_back({v.x, v.y, v.z});
+
+        if (mesh.HasTextureCoords(0)) {
+            const aiVector3D& uv = mesh.mTextureCoords[0][i];
+            out.uvs.push_back({uv.x, uv.y});
+        } else {
+            out.uvs.push_back({0.f, 0.f});
+        }
+    }
+
+    const int material_index = static_cast<int>(mesh.mMaterialIndex);
+    for (unsigned int i = 0; i < mesh.mNumFaces; ++i) {
+        const aiFace& face = mesh.mFaces[i];
+        if (face.mNumIndices != 3)
+            continue;
+        if (face.mIndices[0] >= mesh.mNumVertices ||
+            face.mIndices[1] >= mesh.mNumVertices ||
+            face.mIndices[2] >= mesh.mNumVertices) {
+            error = "Assimp mesh face index is out of bounds";
+            return false;
+        }
+        out.indices.push_back({
+            static_cast<int>(static_cast<size_t>(face.mIndices[0]) + vertex_offset),
+            static_cast<int>(static_cast<size_t>(face.mIndices[1]) + vertex_offset),
+            static_cast<int>(static_cast<size_t>(face.mIndices[2]) + vertex_offset)});
+        out.material_ids.push_back(material_index);
+    }
+
+    vertex_offset += mesh.mNumVertices;
+    return true;
+}
+
+void collect_materials(const aiScene& scene, const boost::filesystem::path& base_dir, TexturedMesh& out)
+{
+    out.material_texture_map.assign(scene.mNumMaterials, -1);
+    out.material_colors.assign(scene.mNumMaterials, {1.f, 1.f, 1.f, 1.f});
+
+    for (unsigned int material_index = 0; material_index < scene.mNumMaterials; ++material_index) {
+        const aiMaterial* material = scene.mMaterials[material_index];
+        if (!material)
+            continue;
+
+        out.material_colors[material_index] = get_material_color(*material);
+
+        aiString texture_path;
+        if (!get_material_texture(*material, texture_path))
+            continue;
+
+        TextureImage image;
+        const aiTexture* embedded_texture = scene.GetEmbeddedTexture(texture_path.C_Str());
+        if (embedded_texture) {
+            if (!read_embedded_texture(*embedded_texture, image))
+                continue;
+        } else {
+            const boost::filesystem::path resolved = resource_path::resolve_external_resource_path(
+                base_dir, texture_path.C_Str(), "Assimp texture");
+            if (resolved.empty()) {
+                BOOST_LOG_TRIVIAL(warning) << "AssimpImport: texture file not found: "
+                                           << texture_path.C_Str();
+                continue;
+            }
+            if (!read_external_texture_file(resolved, image)) {
+                BOOST_LOG_TRIVIAL(warning) << "AssimpImport: failed to read texture: "
+                                           << resolved;
+                continue;
+            }
+        }
+
+        out.material_texture_map[material_index] = static_cast<int>(out.textures.size());
+        out.textures.push_back(std::move(image));
+    }
+}
+
+std::string scene_failure_summary(const std::string& path, const char* assimp_error)
+{
+    std::ostringstream ss;
+    ss << "Assimp failed to import " << path;
+    if (assimp_error && assimp_error[0] != '\0')
+        ss << ": " << assimp_error;
+    return ss.str();
+}
+
+} // namespace
+
+bool load_assimp_textured_model(const std::string& path, TexturedMesh& out, std::string* error_message)
+{
+    clear_textured_mesh(out);
+
+    Assimp::Importer importer;
+    const unsigned int flags = assimp_import_flags(path);
+    configure_importer(importer, path, flags);
+
+    const aiScene* scene = importer.ReadFile(path, flags);
+    if (!scene || (scene->mFlags & AI_SCENE_FLAGS_INCOMPLETE) || !scene->mRootNode) {
+        const std::string message = scene_failure_summary(path, importer.GetErrorString());
+        BOOST_LOG_TRIVIAL(error) << "AssimpImport: " << message;
+        set_error_message(error_message, message);
+        return false;
+    }
+
+    if (scene->mNumMeshes == 0) {
+        const std::string message = "Assimp scene has no meshes: " + path;
+        BOOST_LOG_TRIVIAL(error) << "AssimpImport: " << message;
+        set_error_message(error_message, message);
+        return false;
+    }
+
+    size_t vertex_offset = 0;
+    for (unsigned int mesh_index = 0; mesh_index < scene->mNumMeshes; ++mesh_index) {
+        const aiMesh* mesh = scene->mMeshes[mesh_index];
+        if (!mesh || !mesh->HasPositions())
+            continue;
+        std::string mesh_error;
+        if (!collect_mesh(*mesh, vertex_offset, out, mesh_error)) {
+            const std::string message = mesh_error + ": " + path;
+            BOOST_LOG_TRIVIAL(error) << "AssimpImport: " << message;
+            set_error_message(error_message, message);
+            clear_textured_mesh(out);
+            return false;
+        }
+    }
+
+    if (out.vertices.empty() || out.indices.empty()) {
+        const std::string message = "Assimp extracted no valid triangles: " + path;
+        BOOST_LOG_TRIVIAL(error) << "AssimpImport: " << message;
+        set_error_message(error_message, message);
+        clear_textured_mesh(out);
+        return false;
+    }
+
+    collect_materials(*scene, boost::filesystem::path(path).parent_path(), out);
+
+    BOOST_LOG_TRIVIAL(info) << "AssimpImport: loaded " << out.vertices.size()
+                            << " vertices, " << out.indices.size()
+                            << " triangles, " << out.textures.size()
+                            << " textures from " << path;
+    return true;
+}
+
+} // namespace Slic3r

src/libslic3r/Format/AssimpImport.hpp

@@ -0,0 +1,11 @@
+#pragma once
+
+#include <string>
+
+namespace Slic3r {
+
+struct TexturedMesh;
+
+bool load_assimp_textured_model(const std::string& path, TexturedMesh& out, std::string* error_message = nullptr);
+
+} // namespace Slic3r

src/libslic3r/Format/OBJ.cpp

@@ -1,6 +1,8 @@
 #include "../libslic3r.h"
 #include "../Model.hpp"
 #include "../TriangleMesh.hpp"
+#include "../TexturePainting.hpp"
+#include "ResourcePathUtils.hpp"
 
 #include "OBJ.hpp"
 #include "objparser.hpp"
@@ -8,6 +10,7 @@
 #include <string>
 
 #include <boost/log/trivial.hpp>
+#include <boost/nowide/fstream.hpp>
 
 #ifdef _WIN32
 #define DIR_SEPARATOR '\\'
@@ -21,7 +24,7 @@
 
 namespace Slic3r {
 
-bool load_obj(const char *path, TriangleMesh *meshptr, ObjInfo& obj_info, std::string &message)
+bool load_obj(const char *path, TriangleMesh *meshptr, ObjInfo& obj_info, std::string &message, ObjParser::MtlData *out_mtl)
 {
     if (meshptr == nullptr)
         return false;
@@ -98,6 +101,7 @@ bool load_obj(const char *path, TriangleMesh *meshptr, ObjInfo& obj_info, std::s
     its.indices.reserve(num_faces + num_quads);
     if (exist_mtl) {
         obj_info.is_single_mtl = data.usemtls.size() == 1 && mtl_data.new_mtl_unmap.size() == 1;
+        obj_info.usemtls = data.usemtls;
         obj_info.face_colors.reserve(num_faces + num_quads);
     }
     bool has_color = data.has_vertex_color;
@@ -210,14 +214,17 @@ bool load_obj(const char *path, TriangleMesh *meshptr, ObjInfo& obj_info, std::s
     }
     if (meshptr->volume() < 0)
         meshptr->flip_triangles();
+    // Hand the parsed material table back so callers can build a TexturedMesh from it.
+    if (out_mtl)
+        *out_mtl = mtl_data;
     return true;
 }
 
-bool load_obj(const char *path, Model *model, ObjInfo& obj_info, std::string &message, const char *object_name_in)
+bool load_obj(const char *path, Model *model, ObjInfo& obj_info, std::string &message, const char *object_name_in, ObjParser::MtlData *out_mtl)
 {
     TriangleMesh mesh;
 
-    bool ret = load_obj(path, &mesh, obj_info, message);
+    bool ret = load_obj(path, &mesh, obj_info, message, out_mtl);
 
     if (ret) {
         std::string  object_name;
@@ -232,6 +239,144 @@ bool load_obj(const char *path, Model *model, ObjInfo& obj_info, std::string &me
     return ret;
 }
 
+bool obj_to_textured_mesh(
+    const ObjInfo& obj_info,
+    const indexed_triangle_set& its,
+    const ObjParser::MtlData& mtl_data,
+    const std::string& obj_directory,
+    TexturedMesh& out)
+{
+    if (its.vertices.empty() || its.indices.empty() || !obj_info.has_uv_png)
+        return false;
+
+    const size_t nv = its.vertices.size();
+    const size_t nf = its.indices.size();
+
+    // 1. Copy vertices
+    out.vertices.resize(nv);
+    for (size_t i = 0; i < nv; ++i)
+        out.vertices[i] = {its.vertices[i].x(), its.vertices[i].y(), its.vertices[i].z()};
+
+    // 2. Copy face indices
+    out.indices.resize(nf);
+    for (size_t i = 0; i < nf; ++i)
+        out.indices[i] = {its.indices[i][0], its.indices[i][1], its.indices[i][2]};
+
+    // 3. Build per-face UV (uv_coords + uv_indices)
+    // OBJ UV convention: V=0 at bottom (OpenGL); texture sampling expects V=0 at top (like glTF/OpenCV).
+    // Flip V here so downstream code works uniformly.
+    if (!obj_info.uvs.empty()) {
+        const size_t uv_face_count = obj_info.uvs.size();
+        out.uv_coords.resize(uv_face_count * 3);
+        out.uv_indices.resize(nf);
+        for (size_t fi = 0; fi < nf; ++fi) {
+            if (fi < uv_face_count) {
+                int base = static_cast<int>(fi * 3);
+                out.uv_coords[base + 0] = {obj_info.uvs[fi][0].x(), 1.f - obj_info.uvs[fi][0].y()};
+                out.uv_coords[base + 1] = {obj_info.uvs[fi][1].x(), 1.f - obj_info.uvs[fi][1].y()};
+                out.uv_coords[base + 2] = {obj_info.uvs[fi][2].x(), 1.f - obj_info.uvs[fi][2].y()};
+                out.uv_indices[fi] = {base, base + 1, base + 2};
+            } else {
+                out.uv_indices[fi] = {0, 0, 0};
+            }
+        }
+    }
+
+    // 4. Build material list and load textures from disk
+    // Map: material name -> material index
+    std::map<std::string, int> mtl_name_to_idx;
+    for (size_t i = 0; i < mtl_data.mtl_orders.size(); ++i)
+        mtl_name_to_idx[mtl_data.mtl_orders[i]] = static_cast<int>(i);
+
+    const int num_materials = static_cast<int>(mtl_data.mtl_orders.size());
+    out.material_colors.resize(num_materials, {1.f, 1.f, 1.f, 1.f});
+    out.material_texture_map.resize(num_materials, -1);
+
+    // Map: texture filename -> index in out.textures
+    std::map<std::string, int> png_to_tex_idx;
+
+    for (int mi = 0; mi < num_materials; ++mi) {
+        const std::string& name = mtl_data.mtl_orders[mi];
+        auto it = mtl_data.new_mtl_unmap.find(name);
+        if (it == mtl_data.new_mtl_unmap.end())
+            continue;
+        const auto& mtl = *(it->second);
+
+        // Material color from Kd
+        out.material_colors[mi] = {mtl.Kd[0], mtl.Kd[1], mtl.Kd[2], mtl.Tr};
+
+        // Texture from map_Kd
+        if (mtl.map_Kd.empty())
+            continue;
+
+        auto tex_it = png_to_tex_idx.find(mtl.map_Kd);
+        if (tex_it != png_to_tex_idx.end()) {
+            out.material_texture_map[mi] = tex_it->second;
+            continue;
+        }
+
+        // Resolve texture file path.
+        const boost::filesystem::path requested_tex_path(mtl.map_Kd);
+        const boost::filesystem::path tex_path = requested_tex_path.is_absolute() ?
+            resource_path::resolve_existing_path_case_insensitive(requested_tex_path, "obj_to_textured_mesh: map_Kd") :
+            resource_path::resolve_existing_relative_path_case_insensitive(
+                boost::filesystem::path(obj_directory), requested_tex_path, "obj_to_textured_mesh: map_Kd");
+
+        if (tex_path.empty()) {
+            BOOST_LOG_TRIVIAL(warning) << "obj_to_textured_mesh: texture not found: " << requested_tex_path;
+            continue;
+        }
+
+        // Read raw file bytes
+        boost::nowide::ifstream file(tex_path.string(), std::ios::binary | std::ios::ate);
+        if (!file.is_open())
+            continue;
+        auto file_size = file.tellg();
+        if (file_size <= 0)
+            continue;
+        file.seekg(0, std::ios::beg);
+
+        TextureImage ti;
+        ti.data.resize(static_cast<size_t>(file_size));
+        file.read(reinterpret_cast<char*>(ti.data.data()), file_size);
+        ti.width = -1;
+        ti.height = -1;
+        ti.channels = 0;
+
+        int new_idx = static_cast<int>(out.textures.size());
+        out.textures.push_back(std::move(ti));
+        png_to_tex_idx[mtl.map_Kd] = new_idx;
+        out.material_texture_map[mi] = new_idx;
+    }
+
+    // 5. Build per-face material_ids from usemtls ranges
+    out.material_ids.resize(nf, -1);
+    if (!obj_info.usemtls.empty()) {
+        for (size_t fi = 0; fi < nf; ++fi) {
+            int face_idx = static_cast<int>(fi);
+            for (size_t k = 0; k < obj_info.usemtls.size(); ++k) {
+                const auto& um = obj_info.usemtls[k];
+                if (face_idx >= um.face_start && face_idx <= um.face_end) {
+                    auto name_it = mtl_name_to_idx.find(um.name);
+                    if (name_it != mtl_name_to_idx.end())
+                        out.material_ids[fi] = name_it->second;
+                    break;
+                }
+            }
+        }
+    }
+
+    if (out.textures.empty()) {
+        BOOST_LOG_TRIVIAL(warning) << "obj_to_textured_mesh: no textures loaded";
+        return false;
+    }
+
+    BOOST_LOG_TRIVIAL(info) << "obj_to_textured_mesh: " << nf << " faces, "
+                            << out.textures.size() << " textures, "
+                            << num_materials << " materials";
+    return true;
+}
+
 bool store_obj(const char *path, TriangleMesh *mesh)
 {
     //FIXME returning false even if write failed.

src/libslic3r/Format/OBJ.hpp

@@ -1,6 +1,7 @@
 #ifndef slic3r_Format_OBJ_hpp_
 #define slic3r_Format_OBJ_hpp_
 #include "libslic3r/Color.hpp"
+#include "objparser.hpp"
 #include <unordered_map>
 namespace Slic3r {
 
@@ -18,6 +19,7 @@ struct ObjInfo {
     std::map<std::string,bool>  pngs;
     std::unordered_map<int, std::string> uv_map_pngs;
     bool              has_uv_png{false};
+    std::vector<ObjParser::ObjUseMtl>      usemtls; // material spans, for texture import
 
 };
 struct ObjDialogInOut
@@ -32,8 +34,18 @@ struct ObjDialogInOut
     std::string lost_material_name{""};
 };
 typedef std::function<void(ObjDialogInOut &in_out)> ObjImportColorFn;
-extern bool load_obj(const char *path, TriangleMesh *mesh, ObjInfo &vertex_colors, std::string &message);
-extern bool load_obj(const char *path, Model *model, ObjInfo &vertex_colors, std::string &message, const char *object_name = nullptr);
+extern bool load_obj(const char *path, TriangleMesh *mesh, ObjInfo &vertex_colors, std::string &message, ObjParser::MtlData *out_mtl = nullptr);
+extern bool load_obj(const char *path, Model *model, ObjInfo &vertex_colors, std::string &message, const char *object_name = nullptr, ObjParser::MtlData *out_mtl = nullptr);
+
+struct TexturedMesh;
+// Build a TexturedMesh (vertices + per-face UVs + the texture files named by map_Kd) from a
+// parsed OBJ plus its material table, so the texture-to-color importer can sample face colours.
+extern bool obj_to_textured_mesh(
+    const ObjInfo& obj_info,
+    const indexed_triangle_set& its,
+    const ObjParser::MtlData& mtl_data,
+    const std::string& obj_directory,
+    TexturedMesh& out);
 
 extern bool store_obj(const char *path, TriangleMesh *mesh);
 extern bool store_obj(const char *path, ModelObject *model);

src/libslic3r/Format/ResourcePathUtils.hpp

@@ -0,0 +1,240 @@
+#ifndef slic3r_Format_ResourcePathUtils_hpp_
+#define slic3r_Format_ResourcePathUtils_hpp_
+
+#include <algorithm>
+#include <cctype>
+#include <cstddef>
+#include <string>
+#include <vector>
+
+#include <boost/filesystem.hpp>
+#include <boost/log/trivial.hpp>
+
+namespace Slic3r {
+namespace resource_path {
+
+inline std::string ascii_lower_copy(const std::string& value)
+{
+    std::string lowered;
+    lowered.reserve(value.size());
+    for (unsigned char ch : value)
+        lowered.push_back(static_cast<char>(std::tolower(ch)));
+    return lowered;
+}
+
+inline boost::filesystem::path portable_path_copy(const boost::filesystem::path& value)
+{
+    std::string portable = value.string();
+    std::replace(portable.begin(), portable.end(), '\\', '/');
+    return boost::filesystem::path(portable);
+}
+
+inline int hex_digit_value(char ch)
+{
+    if (ch >= '0' && ch <= '9') return ch - '0';
+    if (ch >= 'a' && ch <= 'f') return ch - 'a' + 10;
+    if (ch >= 'A' && ch <= 'F') return ch - 'A' + 10;
+    return -1;
+}
+
+// Byte-level percent decoding. Per RFC 3986 the %XX byte stream is expected to be
+// UTF-8 when produced from URIs / Assimp aiString; this function performs no
+// transcoding, so callers must treat both input and output as raw UTF-8 bytes.
+inline std::string percent_decode_copy(const std::string& value)
+{
+    std::string decoded;
+    decoded.reserve(value.size());
+    for (std::size_t i = 0; i < value.size(); ++i) {
+        if (value[i] == '%' && i + 2 < value.size()) {
+            const int hi = hex_digit_value(value[i + 1]);
+            const int lo = hex_digit_value(value[i + 2]);
+            if (hi >= 0 && lo >= 0) {
+                decoded.push_back(static_cast<char>((hi << 4) | lo));
+                i += 2;
+                continue;
+            }
+        }
+        decoded.push_back(value[i]);
+    }
+    return decoded;
+}
+
+inline std::string strip_file_uri_prefix_copy(const std::string& value)
+{
+    const std::string lower = ascii_lower_copy(value);
+    if (lower.rfind("file://", 0) != 0)
+        return value;
+
+    std::string path = value.substr(7);
+    if (ascii_lower_copy(path).rfind("localhost/", 0) == 0)
+        path.erase(0, std::string("localhost").size());
+    else if (!path.empty() && path.front() != '/')
+        path = "//" + path;
+
+    // file:///C:/... should become C:/..., while file:///tmp/... keeps /tmp/...
+    if (path.size() >= 3 && path[0] == '/' && std::isalpha(static_cast<unsigned char>(path[1])) && path[2] == ':')
+        path.erase(path.begin());
+    return path;
+}
+
+inline bool file_uri_has_remote_authority(const std::string& value)
+{
+    const std::string lower = ascii_lower_copy(value);
+    if (lower.rfind("file://", 0) != 0)
+        return false;
+
+    const std::string path = value.substr(7);
+    if (path.empty() || path.front() == '/')
+        return false;
+
+    const std::size_t slash = path.find('/');
+    const std::string authority = path.substr(0, slash);
+    return ascii_lower_copy(authority) != "localhost";
+}
+
+inline bool looks_like_windows_absolute_path(const boost::filesystem::path& path)
+{
+    const std::string portable = portable_path_copy(path).string();
+    return portable.size() >= 3
+        && std::isalpha(static_cast<unsigned char>(portable[0]))
+        && portable[1] == ':'
+        && portable[2] == '/';
+}
+
+inline boost::filesystem::path filename_from_portable_path(const boost::filesystem::path& value)
+{
+    const boost::filesystem::path portable = portable_path_copy(value);
+    return portable.filename();
+}
+
+inline boost::filesystem::path find_child_case_insensitive(
+    const boost::filesystem::path& directory,
+    const boost::filesystem::path& requested_name,
+    const char* context)
+{
+    if (!boost::filesystem::exists(directory) || !boost::filesystem::is_directory(directory))
+        return {};
+
+    const std::string requested_lower = ascii_lower_copy(requested_name.filename().string());
+    std::vector<boost::filesystem::path> matches;
+
+    boost::system::error_code ec;
+    for (boost::filesystem::directory_iterator it(directory, ec), end; !ec && it != end; it.increment(ec)) {
+        if (ascii_lower_copy(it->path().filename().string()) == requested_lower)
+            matches.push_back(it->path());
+    }
+
+    if (matches.size() == 1)
+        return matches.front();
+
+    if (matches.size() > 1) {
+        BOOST_LOG_TRIVIAL(warning) << context << ": ambiguous case-insensitive resource match for "
+                                   << requested_name << " in " << directory;
+    }
+
+    return {};
+}
+
+inline boost::filesystem::path resolve_existing_path_case_insensitive(
+    const boost::filesystem::path& requested_path,
+    const char* context = "resource_path")
+{
+    const boost::filesystem::path normalized_path = portable_path_copy(requested_path);
+
+    if (normalized_path.empty())
+        return {};
+
+    if (boost::filesystem::exists(normalized_path))
+        return normalized_path;
+
+    boost::filesystem::path current;
+    bool initialized = false;
+
+    for (const boost::filesystem::path& part : normalized_path) {
+        if (part == normalized_path.root_name() || part == normalized_path.root_directory()) {
+            current /= part;
+            initialized = true;
+            continue;
+        }
+
+        if (!initialized) {
+            current = boost::filesystem::current_path();
+            initialized = true;
+        }
+
+        boost::filesystem::path exact = current / part;
+        if (boost::filesystem::exists(exact)) {
+            current = exact;
+            continue;
+        }
+
+        boost::filesystem::path matched = find_child_case_insensitive(current, part, context);
+        if (matched.empty())
+            return {};
+
+        BOOST_LOG_TRIVIAL(info) << context << ": resolved resource path case-insensitively from "
+                                << exact << " to " << matched;
+        current = matched;
+    }
+
+    return boost::filesystem::exists(current) ? current : boost::filesystem::path();
+}
+
+inline boost::filesystem::path resolve_existing_relative_path_case_insensitive(
+    const boost::filesystem::path& base_dir,
+    const boost::filesystem::path& resource_path,
+    const char* context = "resource_path")
+{
+    const boost::filesystem::path requested = resource_path.is_absolute() ? resource_path : base_dir / resource_path;
+    return resolve_existing_path_case_insensitive(requested, context);
+}
+
+// Resolve a resource path that originated outside our own code (e.g. a glTF/FBX
+// material texture reference or a file:// URI inside a 3MF descriptor).
+//
+// `raw_path` is expected to be UTF-8 regardless of host platform: file URIs are
+// UTF-8 by spec, and Assimp aiString uses UTF-8 internally. Cross-platform
+// correctness on Windows additionally relies on the process having called
+// boost::nowide::nowide_filesystem() during startup (see src/BambuStudio.cpp),
+// which imbues boost::filesystem::path with a UTF-8 codecvt so that
+// `path(std::string)` constructs from UTF-8 byte sequences. Callers that bypass
+// the main entry point (standalone CLI tools, unit tests) must reproduce that
+// setup themselves before invoking this helper.
+inline boost::filesystem::path resolve_external_resource_path(
+    const boost::filesystem::path& base_dir,
+    const std::string& raw_path,
+    const char* context = "resource_path",
+    bool allow_basename_fallback = true)
+{
+    if (raw_path.empty())
+        return {};
+
+    const bool remote_file_uri = file_uri_has_remote_authority(raw_path);
+    const std::string decoded_path = percent_decode_copy(strip_file_uri_prefix_copy(raw_path));
+    const boost::filesystem::path requested = portable_path_copy(boost::filesystem::path(decoded_path));
+
+    boost::filesystem::path resolved = (requested.is_absolute() || looks_like_windows_absolute_path(requested)) ?
+        resolve_existing_path_case_insensitive(requested, context) :
+        resolve_existing_relative_path_case_insensitive(base_dir, requested, context);
+    if (!resolved.empty())
+        return resolved;
+
+    if (!allow_basename_fallback || remote_file_uri)
+        return {};
+
+    const boost::filesystem::path basename = filename_from_portable_path(requested);
+    if (basename.empty())
+        return {};
+
+    resolved = resolve_existing_relative_path_case_insensitive(base_dir, basename, context);
+    if (!resolved.empty()) {
+        BOOST_LOG_TRIVIAL(info) << context << ": resolved resource by basename from "
+                                << requested << " to " << resolved;
+    }
+    return resolved;
+}
+
+} // namespace resource_path
+} // namespace Slic3r
+
+#endif /* slic3r_Format_ResourcePathUtils_hpp_ */

src/libslic3r/Format/bbs_3mf.cpp

@@ -4,6 +4,7 @@
 #include "../Preset.hpp"
 #include "../Utils.hpp"
 #include "../LocalesUtils.hpp"
+#include "../FilamentMixer.hpp"
 #include "../GCode.hpp"
 #include "../Geometry.hpp"
 #include "../GCode/ThumbnailData.hpp"
@@ -246,6 +247,8 @@ static constexpr const char* BUILD_TAG = "build";
 static constexpr const char* ITEM_TAG = "item";
 static constexpr const char* METADATA_TAG = "metadata";
 static constexpr const char* FILAMENT_TAG = "filament";
+static constexpr const char* MIXED_FILAMENT_TAG = "mixed_filament";
+static constexpr const char* MIXED_FILAMENT_COMPONENTS_TAG = "components";
 static constexpr const char* SLICE_WARNING_TAG = "warning";
 static constexpr const char* WARNING_MSG_TAG = "msg";
 static constexpr const char *FILAMENT_ID_TAG   = "id";
@@ -1334,6 +1337,7 @@ void PlateData::parse_filament_info(GCodeProcessorResult *result)
         bool _handle_end_config_metadata();
 
         bool _handle_start_config_filament(const char** attributes, unsigned int num_attributes);
+        bool _handle_start_config_mixed_filament(const char** attributes, unsigned int num_attributes);
         bool _handle_end_config_filament();
 
         bool _handle_start_config_warning(const char** attributes, unsigned int num_attributes);
@@ -2713,6 +2717,14 @@ void PlateData::parse_filament_info(GCodeProcessorResult *result)
                 return;
             }
             BOOST_LOG_TRIVIAL(info) << __FUNCTION__ << boost::format(", load project config file successfully from %1%\n") %dest_file;
+
+            // Heal any gradient-curve slots corrupted by the legacy "|" separator collision
+            // (see FilamentMixer::sanitize_mixed_gradient_curve_array). The 3MF JSON itself
+            // is safe (";" + C-style escape), but older projects saved through the buggy
+            // export_selections/load_selections path may already carry single-point entries
+            // that fail MakerWorld's "curve needs >= 2 points" check.
+            if (auto* curve_opt = config.option<ConfigOptionStrings>("filament_mixed_gradient_curve"))
+                Slic3r::sanitize_mixed_gradient_curve_array(curve_opt->values);
         }
     }
 
@@ -3530,6 +3542,8 @@ void PlateData::parse_filament_info(GCodeProcessorResult *result)
             res = _handle_start_config_plater_instance(attributes, num_attributes);
         else if (::strcmp(FILAMENT_TAG, name) == 0)
             res = _handle_start_config_filament(attributes, num_attributes);
+        else if (::strcmp(MIXED_FILAMENT_TAG, name) == 0)
+            res = _handle_start_config_mixed_filament(attributes, num_attributes);
         else if (::strcmp(SLICE_WARNING_TAG, name) == 0)
             res = _handle_start_config_warning(attributes, num_attributes);
         else if (::strcmp(NOZZLE_TAG, name) == 0)
@@ -4703,6 +4717,23 @@ void PlateData::parse_filament_info(GCodeProcessorResult *result)
         return true;
     }
 
+    bool _BBS_3MF_Importer::_handle_start_config_mixed_filament(const char** attributes, unsigned int num_attributes)
+    {
+        if (m_curr_plater) {
+            std::string id         = bbs_get_attribute_value_string(attributes, num_attributes, FILAMENT_ID_TAG);
+            std::string type       = bbs_get_attribute_value_string(attributes, num_attributes, FILAMENT_TYPE_TAG);
+            std::string color      = bbs_get_attribute_value_string(attributes, num_attributes, FILAMENT_COLOR_TAG);
+            std::string components = bbs_get_attribute_value_string(attributes, num_attributes, MIXED_FILAMENT_COMPONENTS_TAG);
+            PlateMixedFilamentInfo mixed_info;
+            mixed_info.id         = atoi(id.c_str());
+            mixed_info.type       = type;
+            mixed_info.color      = color;
+            mixed_info.components = components;
+            m_curr_plater->mixed_filaments_info.push_back(mixed_info);
+        }
+        return true;
+    }
+
     bool _BBS_3MF_Importer::_handle_end_config_filament()
     {
         // do nothing
@@ -8520,6 +8551,17 @@ void PlateData::parse_filament_info(GCodeProcessorResult *result)
                            << FILAMENT_USED_FOR_SUPPORT << "=\"" << std::boolalpha << it->used_for_support << "\"/>\n";
                 }
 
+                // Mixed (virtual) filaments used by this plate. These are resolved to physical
+                // components before g-code statistics, so they are not present in the <filament>
+                // list above and are recorded separately here.
+                for (auto it = plate_data->mixed_filaments_info.begin(); it != plate_data->mixed_filaments_info.end(); it++)
+                {
+                    stream << "    <" << MIXED_FILAMENT_TAG << " " << FILAMENT_ID_TAG << "=\"" << std::to_string(it->id) << "\" "
+                           << FILAMENT_TYPE_TAG << "=\"" << it->type << "\" "
+                           << FILAMENT_COLOR_TAG << "=\"" << it->color << "\" "
+                           << MIXED_FILAMENT_COMPONENTS_TAG << "=\"" << it->components << "\"/>\n";
+                }
+
                 for (auto it = plate_data->warnings.begin(); it != plate_data->warnings.end(); it++) {
                     stream << "    <" << SLICE_WARNING_TAG << " msg=\"" << it->msg << "\" level=\"" << std::to_string(it->level) << "\" error_code =\"" << it->error_code << "\"  />\n";
                 }

src/libslic3r/Format/bbs_3mf.hpp

@@ -48,6 +48,18 @@ public:
 };
 
 
+// Mixed (virtual) filament used by a plate. Mixed filaments are virtual slots that get
+// resolved to their physical components before g-code statistics, so they never appear in
+// slice_filaments_info. They are recorded here separately so a plate's mixed-color usage
+// can be recovered from slice_info.
+struct PlateMixedFilamentInfo
+{
+    int         id{0};         // 1-based virtual filament slot id
+    std::string type;
+    std::string color;         // blended display color, "#RRGGBB"
+    std::string components;    // 1-based physical component ids, comma separated, e.g. "1,3"
+};
+
 //BBS: define plate data list related structures
 struct PlateData
 {
@@ -89,6 +101,8 @@ struct PlateData
     std::string     first_layer_time;
     std::string     plate_name;
     std::vector<FilamentInfo> slice_filaments_info;
+    // Mixed (virtual) filaments used by this plate; empty when no mixed filament is used.
+    std::vector<PlateMixedFilamentInfo> mixed_filaments_info;
     std::vector<size_t> skipped_objects;
     DynamicPrintConfig config;
     bool            is_support_used {false};

src/libslic3r/Format/objparser.cpp

@@ -262,12 +262,9 @@ static bool obj_parseline(const char *line, ObjData &data)
 				}
                 face_index_count++;
             }
-            if (face_index_count == 3) {//tri
-                data.usemtls.back().face_end++;
-			} else if (face_index_count == 4) {//quad
-                data.usemtls.back().face_end++;
-                data.usemtls.back().face_end++;
-			}
+            if (face_index_count >= 3) {
+                data.usemtls.back().face_end += face_index_count - 2;
+            }
         }
 		vertex.coordIdx			= -1;
 		vertex.normalIdx		= -1;
@@ -374,6 +371,107 @@ static bool obj_parseline(const char *line, ObjData &data)
 	return true;
 }
 static std::string cur_mtl_name = "";
+static bool mtl_is_space(char c)
+{
+    return c == ' ' || c == '\t' || c == '\r';
+}
+
+static const char* mtl_skip_ws(const char *line)
+{
+    while (mtl_is_space(*line))
+        ++line;
+    return line;
+}
+
+static const char* mtl_skip_token(const char *line)
+{
+    while (*line != 0 && !mtl_is_space(*line))
+        ++line;
+    return line;
+}
+
+static bool mtl_token_equals(const char *begin, const char *end, const char *token)
+{
+    const size_t len = static_cast<size_t>(end - begin);
+    return strlen(token) == len && strncmp(begin, token, len) == 0;
+}
+
+static std::string mtl_trim_value(const char *line)
+{
+    const char *begin = mtl_skip_ws(line);
+    const char *end   = begin + strlen(begin);
+    while (end > begin && mtl_is_space(*(end - 1)))
+        --end;
+    return std::string(begin, end);
+}
+
+static bool mtl_skip_numeric_token(const char *&line)
+{
+    const char *begin = mtl_skip_ws(line);
+    if (*begin == 0)
+        return false;
+    char *endptr = 0;
+    strtod(begin, &endptr);
+    if (endptr == begin || (!mtl_is_space(*endptr) && *endptr != 0))
+        return false;
+    line = mtl_skip_ws(endptr);
+    return true;
+}
+
+static bool mtl_skip_required_tokens(const char *&line, int count)
+{
+    for (int i = 0; i < count; ++i) {
+        line = mtl_skip_ws(line);
+        if (*line == 0)
+            return false;
+        line = mtl_skip_token(line);
+    }
+    line = mtl_skip_ws(line);
+    return true;
+}
+
+static std::string mtl_parse_texture_name(const char *line)
+{
+    const char *original = mtl_skip_ws(line);
+    const char *current  = original;
+
+    while (*current == '-') {
+        const char *option_begin = current;
+        const char *option_end   = mtl_skip_token(current);
+        current = option_end;
+
+        if (mtl_token_equals(option_begin, option_end, "-o") ||
+            mtl_token_equals(option_begin, option_end, "-s") ||
+            mtl_token_equals(option_begin, option_end, "-t")) {
+            int skipped = 0;
+            while (skipped < 3 && mtl_skip_numeric_token(current))
+                ++skipped;
+            if (skipped == 0)
+                return mtl_trim_value(original);
+            continue;
+        }
+
+        int option_args = -1;
+        if (mtl_token_equals(option_begin, option_end, "-mm"))
+            option_args = 2;
+        else if (mtl_token_equals(option_begin, option_end, "-bm") ||
+                 mtl_token_equals(option_begin, option_end, "-boost") ||
+                 mtl_token_equals(option_begin, option_end, "-texres") ||
+                 mtl_token_equals(option_begin, option_end, "-clamp") ||
+                 mtl_token_equals(option_begin, option_end, "-blendu") ||
+                 mtl_token_equals(option_begin, option_end, "-blendv") ||
+                 mtl_token_equals(option_begin, option_end, "-cc") ||
+                 mtl_token_equals(option_begin, option_end, "-imfchan") ||
+                 mtl_token_equals(option_begin, option_end, "-type"))
+            option_args = 1;
+
+        if (option_args < 0 || !mtl_skip_required_tokens(current, option_args))
+            return mtl_trim_value(original);
+    }
+
+    return mtl_trim_value(current);
+}
+
 static bool        mtl_parseline(const char *line, MtlData &data)
 {
     if (*line == 0) return true;
@@ -394,13 +492,14 @@ static bool        mtl_parseline(const char *line, MtlData &data)
 			ObjNewMtl new_mtl;
             cur_mtl_name = line;
             data.new_mtl_unmap[cur_mtl_name] = std::make_shared<ObjNewMtl>();
+            data.mtl_orders.emplace_back(cur_mtl_name);
 			break;
 		}
         case 'm': {
             if (*(line++) != 'a' || *(line++) != 'p' || *(line++) != '_' || *(line++) != 'K' || *(line++) != 'd') return false;
             EATWS();
             if (data.new_mtl_unmap.find(cur_mtl_name) != data.new_mtl_unmap.end()) {
-				data.new_mtl_unmap[cur_mtl_name]->map_Kd = line;
+				data.new_mtl_unmap[cur_mtl_name]->map_Kd = mtl_parse_texture_name(line);
 			}
             break;
         }

src/libslic3r/Format/objparser.hpp

@@ -122,6 +122,9 @@ struct MtlData
     // Version of the data structure for load / store in the private binary format.
     int version;
     std::unordered_map<std::string, std::shared_ptr<ObjNewMtl>> new_mtl_unmap;
+    // Material names in declaration order. new_mtl_unmap is unordered, but OBJ material
+    // indices are positional, so texture import needs the original order.
+    std::vector<std::string>                                    mtl_orders;
 };
 extern bool objparse(const char *path, ObjData &data);
 extern bool mtlparse(const char *path, MtlData &data);