VTK 显示3D模型的网格线(线框/wireframe)

在VTK9.1.0在Windows10+VS2019+Qt 5.15.2环境下编译安装的Qt例子中，想显示球体表面的网格线(线框/wireframe)，设置actor的EdgeVisibilityOn属性。

sphereActor->GetProperty()->EdgeVisibilityOn();

全部代码

    QSurfaceFormat::setDefaultFormat(QVTKOpenGLNativeWidget::defaultFormat());

    vtkNew<vtkRenderer> renderer;
    vtkNew<vtkNamedColors> colors;

    vtkNew<vtkSphereSource> sphereSource;

    vtkNew<vtkPolyDataMapper> sphereMapper;
    sphereMapper->SetInputConnection(sphereSource->GetOutputPort());

    vtkNew<vtkActor> sphereActor;
    sphereActor->SetMapper(sphereMapper);
    sphereActor->GetProperty()->SetColor(colors->GetColor4d("Tomato").GetData());
    sphereActor->GetProperty()->EdgeVisibilityOn();

    renderer->AddActor(sphereActor);

    renderer->SetBackground(colors->GetColor3d("SteelBlue").GetData());
    vtkNew<vtkGenericOpenGLRenderWindow> renderWindow;
    renderWindow->AddRenderer(renderer);
    renderWindow->SetWindowName("RenderWindowNoUIFile");
    ui.vtk_main->setRenderWindow(renderWindow);

还可以通过vtkExtractEdges来实现显示全部网格线：

    QSurfaceFormat::setDefaultFormat(QVTKOpenGLNativeWidget::defaultFormat());

    vtkNew<vtkRenderer> renderer;
    vtkNew<vtkNamedColors> colors;

    vtkNew<vtkSphereSource> sphereSource;

    {
        //球体
        vtkNew<vtkPolyDataMapper> sphereMapper;
        sphereMapper->SetInputConnection(sphereSource->GetOutputPort());

        vtkNew<vtkActor> sphereActor;
        sphereActor->SetMapper(sphereMapper);
        sphereActor->GetProperty()->SetColor(colors->GetColor4d("Tomato").GetData());

        renderer->AddActor(sphereActor);
    }

    {
        //网格线
        vtkNew<vtkExtractEdges> extractEdges;
        extractEdges->SetInputConnection(sphereSource->GetOutputPort());

        vtkNew<vtkPolyDataMapper> sphereMapper;
        sphereMapper->SetInputConnection(extractEdges->GetOutputPort());
        vtkNew<vtkActor> sphereActor;
        sphereActor->SetMapper(sphereMapper);
        sphereActor->GetProperty()->SetColor(colors->GetColor4d("Black").GetData());

        renderer->AddActor(sphereActor);
    }

    renderer->SetBackground(colors->GetColor3d("SteelBlue").GetData());
    vtkNew<vtkGenericOpenGLRenderWindow> renderWindow;
    renderWindow->AddRenderer(renderer);
    renderWindow->SetWindowName("RenderWindowNoUIFile");
    ui.vtk_main->setRenderWindow(renderWindow);

编译显示vtkExtractEdges未定义，引入vtkExtractEdges的头文件vtkExtractEdges.h，任何时候vtk类没有定义，头文件是vtk类.h

如下图所示：

还可以通过设置actor的SetRepresentationToWireframe属性来显示网格线：

sphereActor->GetProperty()->SetRepresentationToWireframe();

通过SetRepresentationToWireframe只能显示网格线，不能面和线同时显示。

最后，还可以通过vtkFeatureEdges来显示特定的网格线：

1.边界(boundary)：只被一个多边形使用的边，或者直线单元；
2.非流行(non-manifold)：被三个以上的多边形共用的边；
3.特征边(feature edges)：被两个三角形使用，并且两个三角形之间的夹角大于特征角度（可自行设置此角度）；
4.流行边(manifold edges)：只被两个多边形使用的边。