fbx_import_mesh.cc

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/* SPDX-FileCopyrightText: 2025 Blender Authors
 *
 * SPDX-License-Identifier: GPL-2.0-or-later */

 
#include "BKE_attribute.hh"
#include "BKE_deform.hh"
#include "BKE_key.hh"
#include "BKE_lib_id.hh"
#include "BKE_material.hh"
#include "BKE_mesh.hh"
#include "BKE_modifier.hh"
#include "BKE_object.hh"
#include "BKE_object_deform.h"
 
#include "BLI_color.hh"
#include "BLI_listbase.h"
#include "BLI_ordered_edge.hh"
#include "BLI_string.h"
#include "BLI_task.hh"
#include "BLI_vector_set.hh"
 
#include "BLT_translation.hh"
 
#include "DNA_key_types.h"
#include "DNA_meshdata_types.h"
#include "DNA_object_types.h"
 
#include "IO_fbx.hh"
 
#include "fbx_import_mesh.hh"
 
namespace blender::io::fbx {
 
static constexpr const char *temp_custom_normals_name = "fbx_temp_custom_normals";
 
static bool is_skin_deformer_usable(const ufbx_mesh *mesh, const ufbx_skin_deformer *skin)
{
  return mesh != nullptr && skin != nullptr && skin->clusters.count > 0 &&
         mesh->num_vertices > 0 && skin->vertices.count == mesh->num_vertices;
}
 
static void import_vertex_positions(const ufbx_mesh *fmesh, Mesh *mesh)
{
  MutableSpan<float3> positions = mesh->vert_positions_for_write();
#if 0  // @TODO: "bake" skinned meshes
  if (skin != nullptr) {
    /* For a skinned mesh, transform the vertices into bind pose position, in local space. */
    const ufbx_matrix &geom_to_world = fmesh->instances[0]->geometry_to_world;
    ufbx_matrix world_to_geom = ufbx_matrix_invert(&geom_to_world);
    for (int i = 0; i < fmesh->vertex_position.values.count; i++) {
      ufbx_matrix skin_mat = ufbx_get_skin_vertex_matrix(skin, i, &geom_to_world);
      skin_mat = ufbx_matrix_mul(&world_to_geom, &skin_mat);
      ufbx_vec3 val = ufbx_transform_position(&skin_mat, fmesh->vertex_position.values[i]);
      positions[i] = float3(val.x, val.y, val.z);
      //@TODO: skin normals
    }
    return;
  }
#endif
 
  BLI_assert(positions.size() == fmesh->vertex_position.values.count);
  for (int i = 0; i < fmesh->vertex_position.values.count; i++) {
    ufbx_vec3 val = fmesh->vertex_position.values[i];
    positions[i] = float3(val.x, val.y, val.z);
  }
}
 
static void import_faces(const ufbx_mesh *fmesh, Mesh *mesh)
{
  MutableSpan<int> face_offsets = mesh->face_offsets_for_write();
  MutableSpan<int> corner_verts = mesh->corner_verts_for_write();
  BLI_assert((face_offsets.size() == fmesh->num_faces + 1) ||
             (face_offsets.is_empty() && fmesh->num_faces == 0));
  for (int face_idx = 0; face_idx < fmesh->num_faces; face_idx++) {
    //@TODO: skip < 3 vertex faces?
    const ufbx_face &fface = fmesh->faces[face_idx];
    face_offsets[face_idx] = fface.index_begin;
    for (int i = 0; i < fface.num_indices; i++) {
      int corner_idx = fface.index_begin + i;
      int vidx = fmesh->vertex_indices[corner_idx];
      corner_verts[corner_idx] = vidx;
    }
  }
}
 
static void import_face_material_indices(const ufbx_mesh *fmesh,
                                         bke::MutableAttributeAccessor &attributes)
{
  if (fmesh->face_material.count == fmesh->num_faces) {
    bke::SpanAttributeWriter<int> materials = attributes.lookup_or_add_for_write_only_span<int>(
        "material_index", bke::AttrDomain::Face);
    for (int i = 0; i < fmesh->face_material.count; i++) {
      materials.span[i] = fmesh->face_material[i];
    }
    materials.finish();
  }
}
 
static void import_face_smoothing(const ufbx_mesh *fmesh,
                                  bke::MutableAttributeAccessor &attributes)
{
  if (fmesh->face_smoothing.count > 0 && fmesh->face_smoothing.count == fmesh->num_faces) {
    bke::SpanAttributeWriter<bool> smooth = attributes.lookup_or_add_for_write_only_span<bool>(
        "sharp_face", bke::AttrDomain::Face);
    for (int i = 0; i < fmesh->face_smoothing.count; i++) {
      smooth.span[i] = !fmesh->face_smoothing[i];
    }
    smooth.finish();
  }
}
 
static void import_edges(const ufbx_mesh *fmesh,
                         Mesh *mesh,
                         bke::MutableAttributeAccessor &attributes)
{
  MutableSpan<int2> edges = mesh->edges_for_write();
  BLI_assert(edges.size() == fmesh->num_edges);
  for (int edge_idx = 0; edge_idx < fmesh->num_edges; edge_idx++) {
    const ufbx_edge &fedge = fmesh->edges[edge_idx];
    int va = fmesh->vertex_indices[fedge.a];
    int vb = fmesh->vertex_indices[fedge.b];
    edges[edge_idx] = int2(va, vb);
  }
 
  /* Calculate any remaining edges, and add them to explicitly imported ones.
   * Note that this clears any per-edge data, so we have to setup edge creases etc.
   * after that. */
  bke::mesh_calc_edges(*mesh, true, false);
 
  const bool has_edge_creases = fmesh->edge_crease.count > 0 &&
                                fmesh->edge_crease.count == fmesh->num_edges;
  const bool has_edge_smooth = fmesh->edge_smoothing.count > 0 &&
                               fmesh->edge_smoothing.count == fmesh->num_edges;
  if (has_edge_creases || has_edge_smooth) {
    /* The total number of edges in mesh now might be different from number of explicitly
     * imported ones; we have to build mapping from vertex pairs to edge index. */
    Span<int2> edges = mesh->edges();
    Map<OrderedEdge, int> edge_map;
    edge_map.reserve(edges.size());
    for (const int i : edges.index_range()) {
      edge_map.add(edges[i], i);
    }
 
    if (has_edge_creases) {
      bke::SpanAttributeWriter<float> creases =
          attributes.lookup_or_add_for_write_only_span<float>("crease_edge",
                                                              bke::AttrDomain::Edge);
      creases.span.fill(0.0f);
      for (int i = 0; i < fmesh->num_edges; i++) {
        const ufbx_edge &fedge = fmesh->edges[i];
        int va = fmesh->vertex_indices[fedge.a];
        int vb = fmesh->vertex_indices[fedge.b];
        int edge_i = edge_map.lookup_default({va, vb}, -1);
        if (edge_i >= 0) {
          /* Python fbx importer was squaring the incoming crease values. */
          creases.span[edge_i] = sqrtf(fmesh->edge_crease[i]);
        }
      }
      creases.finish();
    }
 
    if (has_edge_smooth) {
      bke::SpanAttributeWriter<bool> sharp = attributes.lookup_or_add_for_write_only_span<bool>(
          "sharp_edge", bke::AttrDomain::Edge);
      sharp.span.fill(false);
      for (int i = 0; i < fmesh->num_edges; i++) {
        const ufbx_edge &fedge = fmesh->edges[i];
        int va = fmesh->vertex_indices[fedge.a];
        int vb = fmesh->vertex_indices[fedge.b];
        int edge_i = edge_map.lookup_default({va, vb}, -1);
        if (edge_i >= 0) {
          sharp.span[edge_i] = !fmesh->edge_smoothing[i];
        }
      }
      sharp.finish();
    }
  }
}
 
static void import_uvs(const ufbx_mesh *fmesh,
                       bke::MutableAttributeAccessor &attributes,
                       AttributeOwner attr_owner)
{
  for (const ufbx_uv_set &fuv_set : fmesh->uv_sets) {
    std::string attr_name = BKE_attribute_calc_unique_name(attr_owner, fuv_set.name.data);
    bke::SpanAttributeWriter<float2> uvs = attributes.lookup_or_add_for_write_only_span<float2>(
        attr_name, bke::AttrDomain::Corner);
    BLI_assert(fuv_set.vertex_uv.indices.count == uvs.span.size());
    for (int i = 0; i < fuv_set.vertex_uv.indices.count; i++) {
      int val_idx = fuv_set.vertex_uv.indices[i];
      const ufbx_vec2 &uv = fuv_set.vertex_uv.values[val_idx];
      uvs.span[i] = float2(uv.x, uv.y);
    }
    uvs.finish();
  }
}
 
static void import_colors(const ufbx_mesh *fmesh,
                          Mesh *mesh,
                          bke::MutableAttributeAccessor &attributes,
                          AttributeOwner attr_owner,
                          eFBXVertexColorMode color_mode)
{
  std::string first_color_name;
  for (const ufbx_color_set &fcol_set : fmesh->color_sets) {
    std::string attr_name = BKE_attribute_calc_unique_name(attr_owner, fcol_set.name.data);
    if (first_color_name.empty()) {
      first_color_name = attr_name;
    }
    if (color_mode == eFBXVertexColorMode::sRGB) {
      /* sRGB colors, use 4 bytes per color. */
      bke::SpanAttributeWriter<ColorGeometry4b> cols =
          attributes.lookup_or_add_for_write_only_span<ColorGeometry4b>(attr_name,
                                                                        bke::AttrDomain::Corner);
      BLI_assert(fcol_set.vertex_color.indices.count == cols.span.size());
      for (int i = 0; i < fcol_set.vertex_color.indices.count; i++) {
        int val_idx = fcol_set.vertex_color.indices[i];
        const ufbx_vec4 &col = fcol_set.vertex_color.values[val_idx];
        /* Note: color values are expected to already be in sRGB space. */
        float4 fcol = float4(col.x, col.y, col.z, col.w);
        uchar4 bcol;
        rgba_float_to_uchar(bcol, fcol);
        cols.span[i] = ColorGeometry4b(bcol);
      }
      cols.finish();
    }
    else if (color_mode == eFBXVertexColorMode::Linear) {
      /* Linear colors, use 4 floats per color. */
      bke::SpanAttributeWriter<ColorGeometry4f> cols =
          attributes.lookup_or_add_for_write_only_span<ColorGeometry4f>(attr_name,
                                                                        bke::AttrDomain::Corner);
      BLI_assert(fcol_set.vertex_color.indices.count == cols.span.size());
      for (int i = 0; i < fcol_set.vertex_color.indices.count; i++) {
        int val_idx = fcol_set.vertex_color.indices[i];
        const ufbx_vec4 &col = fcol_set.vertex_color.values[val_idx];
        cols.span[i] = ColorGeometry4f(col.x, col.y, col.z, col.w);
      }
      cols.finish();
    }
    else {
      BLI_assert_unreachable();
    }
  }
  if (!first_color_name.empty()) {
    mesh->active_color_attribute = BLI_strdup(first_color_name.c_str());
    mesh->default_color_attribute = BLI_strdup(first_color_name.c_str());
  }
}
 
static bool import_normals_into_temp_attribute(const ufbx_mesh *fmesh,
                                               Mesh *mesh,
                                               bke::MutableAttributeAccessor &attributes)
{
  if (!fmesh->vertex_normal.exists) {
    return false;
  }
  bke::SpanAttributeWriter<float3> normals = attributes.lookup_or_add_for_write_only_span<float3>(
      temp_custom_normals_name, bke::AttrDomain::Corner);
  BLI_assert(fmesh->vertex_normal.indices.count == mesh->corners_num);
  BLI_assert(fmesh->vertex_normal.indices.count == normals.span.size());
  for (int i = 0; i < mesh->corners_num; i++) {
    int val_idx = fmesh->vertex_normal.indices[i];
    const ufbx_vec3 &normal = fmesh->vertex_normal.values[val_idx];
    normals.span[i] = float3(normal.x, normal.y, normal.z);
  }
  normals.finish();
  return true;
}
 
static VectorSet<std::string> get_skin_bone_name_set(const FbxElementMapping &mapping,
                                                     const ufbx_mesh *fmesh)
{
  VectorSet<std::string> name_set;
  for (const ufbx_skin_deformer *skin : fmesh->skin_deformers) {
    if (!is_skin_deformer_usable(fmesh, skin)) {
      continue;
    }
 
    for (const ufbx_skin_cluster *cluster : skin->clusters) {
      if (cluster->num_weights == 0) {
        continue;
      }
 
      std::string bone_name = mapping.node_to_name.lookup_default(cluster->bone_node, "");
      name_set.add(bone_name);
    }
  }
  return name_set;
}
 
static void import_skin_vertex_groups(const FbxElementMapping &mapping,
                                      const ufbx_mesh *fmesh,
                                      Mesh *mesh)
{
  if (fmesh->skin_deformers.count == 0) {
    return;
  }
 
  /* A single mesh can be skinned by several armatures, so we need to build bone (vertex group)
   * name set, taking all skin deformers into account. */
  VectorSet<std::string> bone_set = get_skin_bone_name_set(mapping, fmesh);
  if (bone_set.is_empty()) {
    return;
  }
 
  MutableSpan<MDeformVert> dverts = mesh->deform_verts_for_write();
 
  for (const ufbx_skin_deformer *skin : fmesh->skin_deformers) {
    if (!is_skin_deformer_usable(fmesh, skin)) {
      continue;
    }
 
    for (const ufbx_skin_cluster *cluster : skin->clusters) {
      if (cluster->num_weights == 0) {
        continue;
      }
      std::string bone_name = mapping.node_to_name.lookup_default(cluster->bone_node, "");
      const int group_index = bone_set.index_of_try(bone_name);
      if (group_index < 0) {
        continue;
      }
 
      for (int i = 0; i < cluster->num_weights; i++) {
        const int vertex = cluster->vertices[i];
        if (vertex < dverts.size()) {
          MDeformWeight *dw = BKE_defvert_ensure_index(&dverts[vertex], group_index);
          dw->weight = cluster->weights[i];
        }
      }
    }
  }
}
 
static bool import_blend_shapes(Main &bmain,
                                FbxElementMapping &mapping,
                                const ufbx_mesh *fmesh,
                                Mesh *mesh)
{
  Key *mesh_key = nullptr;
  for (const ufbx_blend_deformer *fdeformer : fmesh->blend_deformers) {
    for (const ufbx_blend_channel *fchan : fdeformer->channels) {
      /* In theory fbx supports multiple keyframes within one blend shape
       * channel; we only take the final target keyframe. */
      if (fchan->target_shape == nullptr) {
        continue;
      }
 
      if (mesh_key == nullptr) {
        mesh_key = BKE_key_add(&bmain, &mesh->id);
        mesh_key->type = KEY_RELATIVE;
        mesh->key = mesh_key;
 
        KeyBlock *kb = BKE_keyblock_add(mesh_key, nullptr);
        BKE_keyblock_convert_from_mesh(mesh, mesh_key, kb);
      }
 
      KeyBlock *kb = BKE_keyblock_add(mesh_key, fchan->target_shape->name.data);
      kb->curval = fchan->weight;
      BKE_keyblock_convert_from_mesh(mesh, mesh_key, kb);
      if (!kb->data) {
        /* Nothing to do. This can happen if the mesh has no vertices. */
        continue;
      }
      float3 *kb_data = static_cast<float3 *>(kb->data);
      for (int i = 0; i < fchan->target_shape->num_offsets; i++) {
        int idx = fchan->target_shape->offset_vertices[i];
        const ufbx_vec3 &delta = fchan->target_shape->position_offsets[i];
        kb_data[idx] += float3(delta.x, delta.y, delta.z);
      }
      mapping.el_to_shape_key.add(&fchan->element, mesh_key);
    }
  }
  return mesh_key != nullptr;
}
 
/* Handle Blender-specific "FullWeights" that for each blend shape also create
 * a weighted vertex group for itself. */
static void import_blend_shape_full_weights(const FbxElementMapping &mapping,
                                            const ufbx_mesh *fmesh,
                                            Mesh *mesh,
                                            Object *obj)
{
  for (const ufbx_blend_deformer *fdeformer : fmesh->blend_deformers) {
    for (const ufbx_blend_channel *fchan : fdeformer->channels) {
      Key *key = mapping.el_to_shape_key.lookup_default(&fchan->element, nullptr);
      if (fchan->target_shape == nullptr || key == nullptr) {
        continue;
      }
      if (fchan->target_shape->offset_weights.count != fchan->target_shape->num_offsets) {
        continue;
      }
 
      KeyBlock *kb = BKE_keyblock_find_name(key, fchan->target_shape->name.data);
      if (kb == nullptr) {
        continue;
      }
 
      /* Ignore cases where all weights are 1.0 (group has no effect),
       * and cases where any weights are outside of 0..1 range (apparently some files have
       * invalid negative weights and should be ignored). */
      bool all_one = true;
      bool all_unorm = true;
      for (ufbx_real w : fchan->target_shape->offset_weights) {
        if (w != 1.0) {
          all_one = false;
        }
        if (w < 0.0 || w > 1.0) {
          all_unorm = false;
        }
      }
      if (all_one || !all_unorm) {
        continue;
      }
 
      int group_index = BKE_defgroup_name_index(&mesh->vertex_group_names, kb->name);
      if (group_index < 0) {
        BKE_object_defgroup_add_name(obj, kb->name);
        group_index = BKE_defgroup_name_index(&mesh->vertex_group_names, kb->name);
        if (group_index < 0) {
          continue;
        }
      }
 
      MutableSpan<MDeformVert> dverts = mesh->deform_verts_for_write();
      for (int i = 0; i < fchan->target_shape->num_offsets; i++) {
        const int idx = fchan->target_shape->offset_vertices[i];
        if (idx >= 0 && idx < dverts.size()) {
          const float w = fchan->target_shape->offset_weights[i];
          MDeformWeight *dw = BKE_defvert_ensure_index(&dverts[idx], group_index);
          dw->weight = w;
        }
      }
 
      STRNCPY(kb->vgroup, kb->name);
    }
  }
}
 
void import_meshes(Main &bmain,
                   const ufbx_scene &fbx,
                   FbxElementMapping &mapping,
                   const FBXImportParams &params)
{
  /* Create Mesh objects outside of Main, in parallel. */
  Vector<Mesh *> meshes(fbx.meshes.count);
  threading::parallel_for_each(IndexRange(fbx.meshes.count), [&](const int64_t index) {
    const ufbx_mesh *fmesh = fbx.meshes.data[index];
    if (fmesh->instances.count == 0) {
      meshes[index] = nullptr; /* Ignore if not used by any objects. */
      return;
    }
 
    /* Create Mesh outside of main. */
    Mesh *mesh = BKE_mesh_new_nomain(
        fmesh->num_vertices, fmesh->num_edges, fmesh->num_faces, fmesh->num_indices);
    bke::MutableAttributeAccessor attributes = mesh->attributes_for_write();
    AttributeOwner attr_owner = AttributeOwner::from_id(&mesh->id);
 
    import_vertex_positions(fmesh, mesh);
    import_faces(fmesh, mesh);
    import_face_material_indices(fmesh, attributes);
    import_face_smoothing(fmesh, attributes);
    import_edges(fmesh, mesh, attributes);
    import_uvs(fmesh, attributes, attr_owner);
    if (params.vertex_colors != eFBXVertexColorMode::None) {
      import_colors(fmesh, mesh, attributes, attr_owner, params.vertex_colors);
    }
    bool has_custom_normals = false;
    if (params.use_custom_normals) {
      /* Mesh validation below can alter the mesh, so we first write custom normals
       * into a temporary custom corner domain attribute, and then re-apply that
       * data as custom normals after the validation. */
      has_custom_normals = import_normals_into_temp_attribute(fmesh, mesh, attributes);
    }
    import_skin_vertex_groups(mapping, fmesh, mesh);
 
    /* Validate if needed. */
    if (params.validate_meshes) {
      bool verbose_validate = false;
#ifndef NDEBUG
      verbose_validate = true;
#endif
      BKE_mesh_validate(mesh, verbose_validate, false);
    }
 
    if (has_custom_normals) {
      /* Actually set custom normals after the validation. */
      bke::SpanAttributeWriter<float3> normals =
          attributes.lookup_or_add_for_write_only_span<float3>(temp_custom_normals_name,
                                                               bke::AttrDomain::Corner);
      bke::mesh_set_custom_normals(*mesh, normals.span);
      normals.finish();
      attributes.remove(temp_custom_normals_name);
    }
 
    meshes[index] = mesh;
  });
 
  /* Create final mesh objects in Main, serially. And do steps that need to be done on the final
   * objects. */
  for (int64_t index : meshes.index_range()) {
    Mesh *mesh = meshes[index];
    if (mesh == nullptr) {
      continue;
    }
    const ufbx_mesh *fmesh = fbx.meshes[index];
    BLI_assert(fmesh != nullptr);
 
    Mesh *mesh_main = static_cast<Mesh *>(
        BKE_object_obdata_add_from_type(&bmain, OB_MESH, get_fbx_name(fmesh->name, "Mesh")));
    BKE_mesh_nomain_to_mesh(mesh, mesh_main, nullptr);
    meshes[index] = mesh_main;
    mesh = mesh_main;
    if (params.use_custom_props) {
      read_custom_properties(fmesh->props, mesh->id, params.props_enum_as_string);
    }
 
    const bool any_shapes = import_blend_shapes(bmain, mapping, fmesh, mesh);
 
    /* Create objects that use this mesh. */
    for (const ufbx_node *node : fmesh->instances) {
      std::string name;
      if (node->is_geometry_transform_helper) {
        /* Name geometry transform adjustment helpers with parent name and _GeomAdjust suffix. */
        name = get_fbx_name(node->parent->name) + std::string("_GeomAdjust");
      }
      else {
        name = get_fbx_name(node->name);
      }
      Object *obj = BKE_object_add_only_object(&bmain, OB_MESH, name.c_str());
      obj->data = mesh_main;
      if (!node->visible) {
        obj->visibility_flag |= OB_HIDE_VIEWPORT;
      }
 
      if (any_shapes) {
        obj->shapenr = 1;
      }
 
      bool matrix_already_set = false;
 
      /* Skinned mesh. */
      if (fmesh->skin_deformers.count > 0) {
        /* Add vertex groups to the object. */
        VectorSet<std::string> bone_set = get_skin_bone_name_set(mapping, fmesh);
        for (const std::string &name : bone_set) {
          BKE_object_defgroup_add_name(obj, name.c_str());
        }
 
        /* Add armature modifiers for each skin deformer. */
        for (const ufbx_skin_deformer *skin : fmesh->skin_deformers) {
          if (!is_skin_deformer_usable(fmesh, skin)) {
            continue;
          }
          Object *arm_obj = nullptr;
          for (const ufbx_skin_cluster *cluster : skin->clusters) {
            if (cluster->num_weights == 0) {
              continue;
            }
            arm_obj = mapping.bone_to_armature.lookup_default(cluster->bone_node, nullptr);
            if (arm_obj != nullptr) {
              break;
            }
          }
          /* Add armature modifier. */
          if (arm_obj != nullptr) {
            ModifierData *md = BKE_modifier_new(eModifierType_Armature);
            STRNCPY(md->name, BKE_id_name(arm_obj->id));
            BLI_addtail(&obj->modifiers, md);
            BKE_modifiers_persistent_uid_init(*obj, *md);
            ArmatureModifierData *ad = reinterpret_cast<ArmatureModifierData *>(md);
            ad->object = arm_obj;
 
            if (!matrix_already_set) {
              matrix_already_set = true;
              obj->parent = arm_obj;
 
              /* We are setting mesh parent to the armature, so set the matrix that is
               * armature-local. Note that the matrix needs to be relative to the FBX
               * node matrix (not the root bone pose matrix). */
              ufbx_matrix world_to_arm = mapping.armature_world_to_arm_node_matrix.lookup_default(
                  arm_obj, ufbx_identity_matrix);
              ufbx_matrix world_to_arm_pose = mapping.armature_world_to_arm_pose_matrix
                                                  .lookup_default(arm_obj, ufbx_identity_matrix);
 
              ufbx_matrix mtx = ufbx_matrix_mul(&world_to_arm, &node->geometry_to_world);
              ufbx_matrix_to_obj(mtx, obj);
 
              /* Setup parent inverse matrix of the mesh, to account for the mesh possibly being in
               * different bind pose than what the node is at. */
              ufbx_matrix mtx_inv = ufbx_matrix_invert(&mtx);
              ufbx_matrix mtx_world = mapping.get_node_bind_matrix(node);
              ufbx_matrix mtx_parent_inverse = ufbx_matrix_mul(&mtx_world, &mtx_inv);
              mtx_parent_inverse = ufbx_matrix_mul(&world_to_arm_pose, &mtx_parent_inverse);
              matrix_to_m44(mtx_parent_inverse, obj->parentinv);
            }
          }
        }
      }
 
      if (any_shapes) {
        import_blend_shape_full_weights(mapping, fmesh, mesh, obj);
      }
 
      /* Assign materials. */
      if (fmesh->materials.count > 0 && node->materials.count == fmesh->materials.count) {
        int mat_index = 0;
        for (int mi = 0; mi < fmesh->materials.count; mi++) {
          const ufbx_material *mesh_fmat = fmesh->materials[mi];
          const ufbx_material *node_fmat = node->materials[mi];
          Material *mesh_mat = mapping.mat_to_material.lookup_default(mesh_fmat, nullptr);
          Material *node_mat = mapping.mat_to_material.lookup_default(node_fmat, nullptr);
          if (mesh_mat != nullptr) {
            mat_index++;
            /* Assign material to the data block. */
            BKE_object_material_assign_single_obdata(&bmain, obj, mesh_mat, mat_index);
 
            /* If object material is different, assign that to object. */
            if (!ELEM(node_mat, nullptr, mesh_mat)) {
              BKE_object_material_assign(&bmain, obj, node_mat, mat_index, BKE_MAT_ASSIGN_OBJECT);
            }
          }
        }
        if (mat_index > 0) {
          obj->actcol = 1;
        }
      }
 
      /* Subdivision. */
      if (params.import_subdivision &&
          fmesh->subdivision_display_mode != UFBX_SUBDIVISION_DISPLAY_DISABLED &&
          (fmesh->subdivision_preview_levels > 0 || fmesh->subdivision_render_levels > 0))
      {
        ModifierData *md = BKE_modifier_new(eModifierType_Subsurf);
        BLI_addtail(&obj->modifiers, md);
        BKE_modifiers_persistent_uid_init(*obj, *md);
 
        SubsurfModifierData *ssd = reinterpret_cast<SubsurfModifierData *>(md);
        ssd->subdivType = SUBSURF_TYPE_CATMULL_CLARK;
        ssd->levels = fmesh->subdivision_preview_levels;
        ssd->renderLevels = fmesh->subdivision_render_levels;
        ssd->boundary_smooth = fmesh->subdivision_boundary ==
                                       UFBX_SUBDIVISION_BOUNDARY_SHARP_CORNERS ?
                                   SUBSURF_BOUNDARY_SMOOTH_PRESERVE_CORNERS :
                                   SUBSURF_BOUNDARY_SMOOTH_ALL;
      }
 
      if (params.use_custom_props) {
        read_custom_properties(node->props, obj->id, params.props_enum_as_string);
      }
      if (!matrix_already_set) {
        node_matrix_to_obj(node, obj, mapping);
      }
      mapping.el_to_object.add(&node->element, obj);
      mapping.imported_objects.add(obj);
    }
  }
}
 
}  // namespace blender::io::fbx