vtk中如何生成一个掩膜，并且与原来stl原型是一样的

在VTK中生成掩膜的方法可以使用vtkPolyDataStencil类，具体步骤如下：

1. 读入STL原型数据并显示：

vtkSmartPointer<vtkSTLReader> reader = vtkSmartPointer<vtkSTLReader>::New();
reader->SetFileName("input.stl");
reader->Update();

vtkSmartPointer<vtkPolyDataMapper> mapper = vtkSmartPointer<vtkPolyDataMapper>::New();
mapper->SetInputConnection(reader->GetOutputPort());

vtkSmartPointer<vtkActor> actor = vtkSmartPointer<vtkActor>::New();
actor->SetMapper(mapper);

vtkSmartPointer<vtkRenderer> renderer = vtkSmartPointer<vtkRenderer>::New();
renderer->AddActor(actor);

vtkSmartPointer<vtkRenderWindow> renderWindow = vtkSmartPointer<vtkRenderWindow>::New();
renderWindow->AddRenderer(renderer);

vtkSmartPointer<vtkRenderWindowInteractor> interactor = vtkSmartPointer<vtkRenderWindowInteractor>::New();
interactor->SetRenderWindow(renderWindow);

renderWindow->Render();
interactor->Start();

2. 生成掩膜并应用到原型上：

// 创建掩膜并初始化为全1
vtkSmartPointer<vtkImageStencilData> stencilData = vtkSmartPointer<vtkImageStencilData>::New();
stencilData->Initialize();
stencilData->SetSpacing(reader->GetOutput()->GetSpacing());
stencilData->SetOrigin(reader->GetOutput()->GetOrigin());
stencilData->SetExtent(reader->GetOutput()->GetExtent());

vtkSmartPointer<vtkPolyDataStencil> stencil = vtkSmartPointer<vtkPolyDataStencil>::New();
stencil->SetInputData(reader->GetOutput());
stencil->SetStencilData(stencilData);
stencil->ReverseStencilOff();
stencil->SetBackgroundValue(0.0);

vtkSmartPointer<vtkImageStencil> imageStencil = vtkSmartPointer<vtkImageStencil>::New();
imageStencil->SetInputData(0, reader->GetOutput());
imageStencil->SetInputData(1, stencilData);
imageStencil->SetStencil(stencil);
imageStencil->SetBackgroundValue(0.0);
imageStencil->Update();

vtkSmartPointer<vtkImageData> mask = vtkSmartPointer<vtkImageData>::New();
mask->DeepCopy(imageStencil->GetOutput());

// 显示掩膜
vtkSmartPointer<vtkImageActor> maskActor = vtkSmartPointer<vtkImageActor>::New();
maskActor->SetInputData(mask);

vtkSmartPointer<vtkRenderer> maskRenderer = vtkSmartPointer<vtkRenderer>::New();
maskRenderer->AddActor(maskActor);

vtkSmartPointer<vtkRenderWindow> maskRenderWindow = vtkSmartPointer<vtkRenderWindow>::New();
maskRenderWindow->AddRenderer(maskRenderer);

vtkSmartPointer<vtkRenderWindowInteractor> maskInteractor = vtkSmartPointer<vtkRenderWindowInteractor>::New();
maskInteractor->SetRenderWindow(maskRenderWindow);

maskRenderWindow->Render();
maskInteractor->Start();

// 将掩膜应用到原型上
vtkSmartPointer<vtkImageMask> imageMask = vtkSmartPointer<vtkImageMask>::New();
imageMask->SetInputData(reader->GetOutput());
imageMask->SetMaskData(mask);
imageMask->Update();

vtkSmartPointer<vtkPolyDataMapper> maskMapper = vtkSmartPointer<vtkPolyDataMapper>::New();
maskMapper->SetInputData(imageMask->GetOutput());

vtkSmartPointer<vtkActor> maskActor = vtkSmartPointer<vtkActor>::New();
maskActor->SetMapper(maskMapper);

renderer->AddActor(maskActor);

这样，就能够生成一个与原来STL原型一样的掩膜，并且应用到原型上。