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我想在nifti標籤集上運行vtkMarchingCubes。我想要生成曲面的體素區域都具有相同的值。我有兩個問題。首先，我似乎錯誤地設置了算法，因爲生成的vtkPolyData顯然沒有頂點。其次，從vtkOBJExporter文檔中我不清楚如何將vtkPolyData導出爲波前.OBJ文件。如果任何人看到下面的代碼的任何問題，或者可以告訴我如何將vtkPolyData作爲OBJ導出，我將不勝感激。vtkMarchingCubes將nifti曲面導出到波前OBJ
//Read The Nifti Label File
string input_path = "/MyPath/labels.nii";
nifti_image *im = nifti_image_read(input_path.c_str(),true);
cout<<im->nx<<","<<im->ny<<","<<im->nz<<endl; //Confirms Read Works
// Set up vtk image data
vtkImageImport* importer = vtkImageImport::New();
importer->SetImportVoidPointer((void*)im->data);
importer->SetDataScalarTypeToFloat();
importer->SetDataExtent(0, im->nx-1, 0, im->ny-1, 0, im->nz-1);
importer->SetWholeExtent(0, im->nx-1, 0, im->ny-1, 0, im->nz-1);
vtkImageData* point_cloud = importer->GetOutput();
point_cloud->SetScalarTypeToFloat();
point_cloud->SetExtent(0, im->nx-1, 0, im->ny-1, 0, im->nz-1);
point_cloud->SetSpacing(im->dx, im->dy, im->dz);
//Apply Threshold To Cut Out Other Data
//Is this needed or will Marching Cubes properly identify the region
vtkImageThreshold* threshold = vtkImageThreshold::New();
threshold->ThresholdBetween(label_number,label_number);
threshold->SetInValue(255);
threshold->SetOutValue(0);
threshold->SetInput(point_cloud);
//Apply the Marching Cubes algorithm
vtkMarchingCubes* marching_cubes = vtkMarchingCubes::New();
marching_cubes->SetValue(0, 127.0f);
marching_cubes->SetInput(threshold->GetOutput()); //(vtkDataObject*)point_cloud);
vtkPolyData* surface = marching_cubes->GetOutput();
marching_cubes->Update();
//See That Marching Cubes Worked
cout<<"# Vertices: "<< surface->GetNumberOfVerts()<<endl;
cout<<"# Cells: "<< surface->GetNumberOfCells()<<endl;
//Export (How is this done properly?)
vtkOBJExporter* exporter = vtkOBJExporter::New();
exporter->SetInput(vtkRenderWindow *renWin); //I don't want a render window, I want at file
exporter->SetFilePrefix("/MyPath/surface");
exporter->Write();