vtkPolyData相关操作文档

一、vtkPolyData细化

vtkPolyData是VTK的一个中心数据结构，表示一个三维几何图形。对于几何形状的细化，我们可以使用一些算法来使几何形状更加精细化。vtkPolyData中提供了两种细化技术：一种是三角剖分，另一种是曲面重建。下面是三角剖分的代码示例:

vtkSmartPointer<vtkTriangleFilter> triangleFilter =
  vtkSmartPointer<vtkTriangleFilter>::New();
triangleFilter->SetInputData(polyData);
triangleFilter->Update();

下面是曲面重建的代码示例:

vtkSmartPointer<vtkSurfaceReconstructionFilter> surf =
  vtkSmartPointer<vtkSurfaceReconstructionFilter>::New();
surf->SetInputConnection(reader->GetOutputPort());
surf->Update();
vtkSmartPointer<vtkPolyData> polyData = surf->GetOutput();

二、vtkPolyDataConnectivity

在计算几何形状时，我们经常需要提取特定区域的信息。vtkPolyDataConnectivity可以帮助我们实现这一目标。下面是vtkPolyDataConnectivity的代码示例:

vtkSmartPointer<vtkPolyDataConnectivityFilter> connectFilter =
    vtkSmartPointer<vtkPolyDataConnectivityFilter>::New();
connectFilter->SetInputData(polyData);
connectFilter->SetExtractionModeToLargestRegion();
connectFilter->Update();
vtkPolyData* connected = connectFilter->GetOutput();

三、vtkPolyData隐藏

在特定情况下，我们需要隐藏掉一部分几何形状，以便更好地展示其它部分。下面是vtkActor在vtkPolyData上的调用示例:

vtkSmartPointer<vtkActor> actor = 
  vtkSmartPointer<vtkActor>::New();
actor->SetMapper(mapper);
actor->GetProperty()->SetOpacity(0.5);
renderer->AddActor(actor);

四、vtkPolyDataConnectivityFilter

除了vtkPolyDataConnectivity，vtkPolyDataConnectivityFilter是另一个有用的类，可以帮助我们查找和处理特定几何区域。下面是vtkPolyDataConnectivityFilter的代码示例:

vtkSmartPointer<vtkPolyDataConnectivityFilter> connectFilter =
    vtkSmartPointer<vtkPolyDataConnectivityFilter>::New();
connectFilter->SetInputData(polyData);
connectFilter->SetExtractionModeToLargestRegion();
connectFilter->Update();
vtkPolyData* connected = connectFilter->GetOutput();

五、vtkPolyData保存

在VTK中，我们可以使用多种文件格式来保存vtkPolyData。下面是vtkPolyData保存为.vtk文件的代码示例:

vtkSmartPointer<vtkPolyDataWriter> writer =
    vtkSmartPointer<vtkPolyDataWriter>::New();
writer->SetFileName("output.vtk");
writer->SetInputData(polyData);
writer->Write();

六、vtkPolyData随控件一起运动

在某些情况下，我们需要让vtkPolyData随着控件的变化而进行相应的运动。下面是vtkPolyData随控件一起运动的代码示例:

vtkSmartPointer<vtkTransform> transform =
    vtkSmartPointer<vtkTransform>::New();
transform->Translate(1.0, 0.0, 0.0);
actor->SetUserTransform(transform);

七、vtkPolyData存储线

在VTK中，我们可以使用vtkPolyData存储线的几何信息。下面是vtkPolyData存储线的示例代码:

vtkSmartPointer<vtkPolyData> polyData =
    vtkSmartPointer<vtkPolyData>::New();
vtkSmartPointer<vtkCellArray> lines =
    vtkSmartPointer<vtkCellArray>::New();
vtkSmartPointer<vtkPolyLine> polyLine =
    vtkSmartPointer<vtkPolyLine>::New();
polyLine->GetPointIds()->SetNumberOfIds(2);
polyLine->GetPointIds()->SetId(0, 0);
polyLine->GetPointIds()->SetId(1, 1);
lines->InsertNextCell(polyLine);
polyData->SetLines(lines);

八、vtkPolyData写入vtu

在VTK中，我们可以使用多种格式输出vtkPolyData，.vtu是一种常用的格式。下面是vtkPolyData写入.vtu的代码示例:

vtkSmartPointer<vtkXMLUnstructuredGridWriter> writer =
    vtkSmartPointer<vtkXMLUnstructuredGridWriter>::New();
writer->SetInputData(polyData);
writer->SetFileName("output.vtu");
writer->Write();

九、vtkPolyData平滑和缩放

在VTK中，我们可以使用vtkSmoothPolyDataFilter和vtkTransformFilter对vtkPolyData进行平滑和缩放。下面是vtkPolyData平滑和缩放的代码示例:

vtkSmartPointer<vtkSmoothPolyDataFilter> smoothFilter =
    vtkSmartPointer<vtkSmoothPolyDataFilter>::New();
smoothFilter->SetInputData(polyData);
smoothFilter->SetNumberOfIterations(10);
smoothFilter->Update();
vtkSmartPointer<vtkTransformFilter> transformFilter =
    vtkSmartPointer<vtkTransformFilter>::New();
transformFilter->SetInputConnection(smoothFilter->GetOutputPort());
vtkSmartPointer<vtkTransform> transform =
    vtkSmartPointer<vtkTransform>::New();
transform->Scale(2.0, 2.0, 2.0);
transformFilter->SetTransform(transform);
transformFilter->Update();
vtkPolyData* polyDataOut = transformFilter->GetOutput();

十、vtkPolyDataMapper选取

vtkPolyDataMapper可以帮助vtkPolyData渲染出来。下面是vtkPolyDataMapper选取的代码示例:

vtkSmartPointer<vtkPolyDataMapper> mapper =
    vtkSmartPointer<vtkPolyDataMapper>::New();
mapper->SetInputData(polyData);
mapper->SetScalarVisibility(0);
actor->SetMapper(mapper);
actor->GetProperty()->SetColor(1, 0, 0);

VTKPolyData的多方面阐述