Assimp中未加载网格

Question

要在网格中加载，我使用来自Assimp的Importer::ReadFile()。

在Assimp的文档中，它指出aiMesh::mVertices和aiMesh::mFaces总是被定义的。当我加载stl文件时，定义了顶点，但没有定义面。我的场景只包含一个网格，并且应该包含这个网格的面的指针始终是1B1B1B1B1B1B1B。

我在网上找到的唯一一个类似的问题就是这个https://sourceforge.net/p/assimp/discussion/817654/thread/a7c953a7/。他也有同样的问题，只是指针是空指针。他通过使用较新版本的Assimp解决了这个问题，即assimp 3.0.1264。我使用的是Assimp 5.0.4162681867，所以我认为这是可以的，但我还没有尝试他的特定版本。

我的代码和输出如下

Assimp::DefaultLogger::create("", Assimp::Logger::VERBOSE, aiDefaultLogStream_STDOUT);


    // Create an instance of the Importer class
    Assimp::Importer importer;

    const aiScene* temp_scene = importer.ReadFile( file,
      aiProcess_CalcTangentSpace       |
      aiProcess_GenNormals             |
      aiProcess_Triangulate            |
      aiProcess_JoinIdenticalVertices  |
      aiProcess_SortByPType            |
      aiProcess_ValidateDataStructure
      );

    //kill here the logger, just to see what has happened with the importer
    Assimp::DefaultLogger::kill();

    //check if scene
      if (temp_scene == NULL)
      {
            std::cout << __LINE__ << ": Error importing scene. Check if file exists ! " << std::endl;
            return -1;
      }
      else
      {
          int meshIdx = temp_scene->mRootNode->mChildren[0]->mMeshes[0];
          std::cout << __LINE__ << ": idx " << meshIdx << std::endl;
          std::cout << __LINE__ << ": mNumFaces: " << temp_scene->mMeshes[meshIdx]->mNumFaces << std::endl;
          std::cout << __LINE__ << ": HasFaces(): " << temp_scene->mMeshes[meshIdx]->HasFaces() << std::endl;
          std::cout << __LINE__ << ": ptr mFace[0]: " << &(temp_scene->mMeshes[meshIdx]->mFaces[0]) << std::endl;
      }

    exit(0);

Info,  T21520: Load C:/Users/Woute/Documents/2021-2022/computationalFabrication/files/balanced_die.stl
Debug, T21520: Assimp 5.0.4162681867 amd64 msvc debug shared singlethreadedsingle : 
Info,  T21520: Found a matching importer for this file format: Stereolithography (STL) Importer.
Info,  T21520: Import root directory is 'C:/Users/Woute/Documents/2021-2022/computationalFabrication/files\'
Info,  T21520: STL: Taking code path for Materialise files
Debug, T21520: UpdateImporterScale scale set: 1
Debug, T21520: ValidateDataStructureProcess begin
Debug, T21520: ValidateDataStructureProcess end
Info,  T21520: Entering post processing pipeline
Debug, T21520: TriangulateProcess begin
Debug, T21520: TriangulateProcess finished. There was nothing to be done.
Debug, T21520: SortByPTypeProcess begin
Info,  T21520: Points: 0, Lines: 0, Triangles: 1, Polygons: 0 (Meshes, X = removed)
Debug, T21520: SortByPTypeProcess finished
Debug, T21520: GenFaceNormalsProcess begin
Debug, T21520: GenFaceNormalsProcess finished. Normals are already there
Debug, T21520: Generate spatially-sorted vertex cache
Debug, T21520: CalcTangentsProcess begin
Error, T21520: Failed to compute tangents; need UV data in channel0
Debug, T21520: CalcTangentsProcess finished
Debug, T21520: JoinVerticesProcess begin
Info,  T21520: JoinVerticesProcess finished | Verts in: 6486 out: 4029 | ~37.8816
Info,  T21520: Leaving post processing pipeline
47/ idx0
48: mNumFaces: 2162
49: HasFaces(): 1
50: ptr mFace[0]: 1B1B1B1B1B1B1B1B

Answer 1

检查你的日志后，我猜你的模型中只有一个三角形，但有6486个顶点。

您是否正在使用点云模型？如果没有:您可以在我们项目空间中为该模型创建一个新的问题报告，网址为Github