[vtkusers] help needed with vtkBoxClipDataSet()

WolfgangZ wollez at gmx.net
Thu Oct 18 12:48:16 EDT 2007


Hi,

I clip a unstructured mesh with vtkBoxClipDataSet. It displays correct 
but extracting information about cells, nodes and boundingbox os wrong. 
Here partially the code:

  connect2 = vtk.vtkConnectivityFilter()
  connect2.SetInput(aTriangleGrid)

  ### clipping the cells (but triangulation)
  boxCut = vtk.vtkBoxClipDataSet()
  boxCut.SetBoxClip(0.001,0.005,0.001,0.005,-1,1)
  boxCut.SetInputConnection(connect2.GetOutputPort())
  boxCut.GenerateClipScalarsOff()
  boxCut.Update()

  partGrid=vtk.vtkUnstructuredGrid()
  partGrid=boxCut.GetOutput()
  print partGrid.GetBounds()

the print results in this:
  (0.0004729999927803874, 0.0053309998475015163, 0.00048099999548867345, 
  0.006076000165194273, 0.0, 0.0)

  Also when I loop over the nodes "partGrid: by the following code I 
only get coordinates in that value range.
  npoints_cut=boxCut.GetOutput().GetNumberOfPoints()
  for i in xrange(0,npoints_cut):
     coord=boxCut.GetOutput().GetPoints().GetPoint(i)
     print repr(coord[0]), repr(coord[1])

What I absolutely dont understand is that it displays correctly!
the visualisation is done by:
  cutMapper = vtk.vtkDataSetMapper()
  cutMapper.SetInput(partGrid)
  cutActor = vtk.vtkActor()
  cutActor.SetMapper(cutMapper)
  cutActor.GetProperty().SetRepresentationToWireframe()

  ren = vtk.vtkRenderer()
  renWin = vtk.vtkRenderWindow()
  renWin.AddRenderer(ren)
  renWin.SetSize(300, 300)
  iren = vtk.vtkRenderWindowInteractor()
  interactor=vtk.vtkInteractorStyleTerrain()
  iren.SetInteractorStyle(interactor)
  iren.SetRenderWindow(renWin)

  ren.SetBackground(1, 1, 1)
  ren.AddActor(cutActor)
  ren.ResetCamera()
  ren.GetActiveCamera().Azimuth(0)
  ren.GetActiveCamera().Elevation(0)
  ren.ResetCameraClippingRange()

  # Render the scene and start interaction.
  iren.Initialize()
  interactor=vtk.vtkInteractorStyleTerrain()
  iren.SetInteractorStyle(interactor)

  renWin.Render()
  iren.Start()


So any help is welcome!
Regards
Wolfgang




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