问ASSIMP导出导入的场景而不做任何更改时抛出异常

EN

int main(int argc, char** argv)
{
    string filename = "../Content/PinocchioMesh/Model1.obj";

    Assimp::Importer Importer;
    //Importer.
    cout << "\tReading file using ASSIMP" << endl;
    const aiScene* aiscene = Importer.ReadFile(filename.c_str(), aiProcess_JoinIdenticalVertices | \
        aiProcess_GenSmoothNormals | aiProcess_FlipUVs | aiProcess_SortByPType | aiProcess_Triangulate);

    string str = Importer.GetErrorString();

    if (!aiscene) {
        printf("Error parsing '%s': '%s'\n", filename.c_str(), Importer.GetErrorString());
        return false;
    }


    Assimp::Exporter exporter;
    const aiExportFormatDesc* format = exporter.GetExportFormatDescription(0);
    int lIndex = filename.find_last_of('/');
    //const string path = Filename.substr(0,lIndex+1);
    string path = "../Content/PinocchioMesh/";
    cout << "\tExport path: " << path << endl;
    aiReturn ret = exporter.Export(aiscene, format->id, path, aiscene->mFlags);
    cout << exporter.GetErrorString() << endl;

    return 0;
}

First-chance exception at 0x1052591B (Assimp32.dll) in ImportRigExport.exe: 0xC0000005: Access violation reading location 0x00000000.