sweep polygonal data creating "skirt" from free edges and lines, and lines from vertices
vtkQuadRotationalExtrusionFilter is a modeling filter. It takes polygonal data as input and generates polygonal data on output. The input dataset is swept around the z-axis to create new polygonal primitives. These primitives form a "skirt" or swept surface. For example, sweeping a line results in a cylindrical shell, and sweeping a circle creates a torus.
There are a number of control parameters for this filter. You can control whether the sweep of a 2D object (i.e., polygon or triangle strip) is capped with the generating geometry via the "Capping" instance variable. Also, you can control the angle of rotation, and whether translation along the z-axis is performed along with the rotation. (Translation is useful for creating "springs".) You also can adjust the radius of the generating geometry using the "DeltaRotation" instance variable.
The skirt is generated by locating certain topological features. Free edges (edges of polygons or triangle strips only used by one polygon or triangle strips) generate surfaces. This is true also of lines or polylines. Vertices generate lines.
This filter can be used to model axisymmetric objects like cylinders, bottles, and wine glasses; or translational/rotational symmetric objects like springs or corkscrews.
Definition at line 74 of file vtkQuadRotationalExtrusionFilter.h.
示例代码：
#ifndef INITIAL_OPENGL #define INITIAL_OPENGL #include <vtkAutoInit.h> VTK_MODULE_INIT(vtkRenderingOpenGL) VTK_MODULE_INIT(vtkInteractionStyle) #endif #include <iostream> using namespace std; #include "vtkCamera.h" #include "vtkInformation.h" #include "vtkLineSource.h" #include "vtkMultiBlockDataSet.h" #include "vtkNew.h" #include "vtkPolyDataMapper.h" #include "vtkPolyDataNormals.h" #include "vtkProperty.h" #include "vtkRegressionTestImage.h" #include "vtkRenderer.h" #include "vtkRenderWindow.h" #include "vtkRenderWindowInteractor.h" #include "vtkQuadRotationalExtrusionFilter.h" #include "vtkTestUtilities.h" int main() { // Create a line source vtkNew<vtkLineSource> line; line->SetPoint1( 0., 1., 0. ); line->SetPoint2( 0., 1., 2. ); line->SetResolution( 10 ); line->Update(); // Create mapper for line segment vtkNew<vtkPolyDataMapper> lineMapper; lineMapper->SetInputConnection( line->GetOutputPort() ); // Create actor for line segment vtkNew<vtkActor> lineActor; lineActor->SetMapper( lineMapper.GetPointer() ); lineActor->GetProperty()->SetLineWidth( 5 ); lineActor->GetProperty()->SetColor( 0., .749, 1. ); // deep sky blue // Create multi-block data set for quad-based sweep vtkNew<vtkMultiBlockDataSet> lineMB; lineMB->SetNumberOfBlocks( 1 ); lineMB->GetMetaData( static_cast<unsigned>( 0 ) )->Set( vtkCompositeDataSet::NAME(), "Line" ); lineMB->SetBlock( 0, line->GetOutput() ); // Create 3/4 of a cylinder by rotational extrusion vtkNew<vtkQuadRotationalExtrusionFilter> lineSweeper; lineSweeper->SetResolution( 20 ); lineSweeper->SetInputData( lineMB.GetPointer() ); lineSweeper->SetDefaultAngle( 270 ); lineSweeper->Update(); // Retrieve polydata output vtkMultiBlockDataSet* cylDS = vtkMultiBlockDataSet::SafeDownCast( lineSweeper->GetOutputDataObject( 0 ) ); vtkPolyData* cyl = vtkPolyData::SafeDownCast( cylDS->GetBlock( 0 ) ); // Create normals for smooth rendering vtkNew<vtkPolyDataNormals> normals; normals->SetInputData( cyl ); // Create mapper for surface representation vtkNew<vtkPolyDataMapper> cylMapper; cylMapper->SetInputConnection( normals->GetOutputPort() ); cylMapper->SetResolveCoincidentTopologyToPolygonOffset(); // Create mapper for wireframe representation vtkNew<vtkPolyDataMapper> cylMapperW; cylMapperW->SetInputData( cyl ); cylMapperW->SetResolveCoincidentTopologyToPolygonOffset(); // Create actor for surface representation vtkNew<vtkActor> cylActor; cylActor->SetMapper( cylMapper.GetPointer() ); cylActor->GetProperty()->SetRepresentationToSurface(); cylActor->GetProperty()->SetInterpolationToGouraud(); cylActor->GetProperty()->SetColor( 1., 0.3882, .2784 ); // tomato // Create actor for wireframe representation vtkNew<vtkActor> cylActorW; cylActorW->SetMapper( cylMapperW.GetPointer() ); cylActorW->GetProperty()->SetRepresentationToWireframe(); cylActorW->GetProperty()->SetColor( 0., 0., 0.); cylActorW->GetProperty()->SetAmbient( 1. ); cylActorW->GetProperty()->SetDiffuse( 0. ); cylActorW->GetProperty()->SetSpecular( 0. ); // Create a renderer, add actors to it vtkNew<vtkRenderer> ren1; ren1->AddActor( lineActor.GetPointer() ); ren1->AddActor( cylActor.GetPointer() ); ren1->AddActor( cylActorW.GetPointer() ); ren1->SetBackground( 1., 1., 1. ); // Create a renderWindow vtkNew<vtkRenderWindow> renWin; renWin->AddRenderer( ren1.GetPointer() ); renWin->SetSize( 300, 300 ); renWin->SetMultiSamples( 0 ); // Create a good view angle vtkNew<vtkCamera> camera; camera->SetClippingRange( 0.576398, 28.8199 ); camera->SetFocalPoint( 0.0463079, -0.0356571, 1.01993 ); camera->SetPosition( -2.47044, 2.39516, -3.56066 ); camera->SetViewUp( 0.607296, -0.513537, -0.606195 ); ren1->SetActiveCamera( camera.GetPointer() ); // Create interactor vtkNew<vtkRenderWindowInteractor> iren; iren->SetRenderWindow( renWin.GetPointer() ); // Render and test renWin->Render(); iren->Start(); return 0; }
运行显示结果：
旋转扫描实体示例：vtkQuadRotationalExtrusionFilter
原文：http://www.cnblogs.com/phoenixdsg/p/7511099.html