Cube
VTKExamples/Python/DataManipulation/Cube
Description¶
This is a transliteration of the C++ example Examples/DataManipulation/Cxx/Cube.cxx in the VTK source distribution.
It illustrates the manual use of vtkPolyData to construct a cube and differs from the Wiki examples Cube and Cube, which use vtkCube.
Code¶
Cube.py
#!/usr/bin/env python # This is (almost) a direct C++ to Python transliteration of # <VTK-root>/Examples/DataManipulation/Cxx/Cube.cxx from the VTK # source distribution, which "shows how to manually create vtkPolyData" # # A convenience function, mkVtkIdList(), has been added and one if/else # so the example also works in version 6 or later. # # Lines like `obj->Delete()` have been transliterated as `del obj` to, # preserve the resemblance to the original C++ example, although I # doubt this achieves anything beyond what Python's garbage collection # would do anyway. import vtk # Makes a vtkIdList from a Python iterable. I'm kinda surprised that # this is necessary, since I assumed that this kind of thing would # have been built into the wrapper and happen transparently, but it # seems not. def mkVtkIdList(it): vil = vtk.vtkIdList() for i in it: vil.InsertNextId(int(i)) return vil def main(): # x = array of 8 3-tuples of float representing the vertices of a cube: x = [(0.0, 0.0, 0.0), (1.0, 0.0, 0.0), (1.0, 1.0, 0.0), (0.0, 1.0, 0.0), (0.0, 0.0, 1.0), (1.0, 0.0 ,1.0), (1.0, 1.0, 1.0), (0.0, 1.0, 1.0)] # pts = array of 6 4-tuples of vtkIdType (int) representing the faces # of the cube in terms of the above vertices pts = [(0,1,2,3), (4,5,6,7), (0,1,5,4), (1,2,6,5), (2,3,7,6), (3,0,4,7)] # We'll create the building blocks of polydata including data attributes. cube = vtk.vtkPolyData() points = vtk.vtkPoints() polys = vtk.vtkCellArray() scalars = vtk.vtkFloatArray() # Load the point, cell, and data attributes. for i in range(8): points.InsertPoint(i, x[i]) for i in range(6): polys.InsertNextCell( mkVtkIdList(pts[i]) ) for i in range(8): scalars.InsertTuple1(i,i) # We now assign the pieces to the vtkPolyData. cube.SetPoints(points) del points cube.SetPolys(polys) del polys cube.GetPointData().SetScalars(scalars) del scalars # Now we'll look at it. cubeMapper = vtk.vtkPolyDataMapper() if vtk.VTK_MAJOR_VERSION <= 5: cubeMapper.SetInput(cube) else: cubeMapper.SetInputData(cube) cubeMapper.SetScalarRange(0,7) cubeActor = vtk.vtkActor() cubeActor.SetMapper(cubeMapper) # The usual rendering stuff. camera = vtk.vtkCamera() camera.SetPosition(1,1,1) camera.SetFocalPoint(0,0,0) renderer = vtk.vtkRenderer() renWin = vtk.vtkRenderWindow() renWin.AddRenderer(renderer) iren = vtk.vtkRenderWindowInteractor() iren.SetRenderWindow(renWin) renderer.AddActor(cubeActor) renderer.SetActiveCamera(camera) renderer.ResetCamera() renderer.SetBackground(1,1,1) renWin.SetSize(300,300) # interact with data renWin.Render() iren.Start() # Clean up del cube del cubeMapper del cubeActor del camera del renderer del renWin del iren main()