text: #!/usr/bin/env python
  import vtk
  from vtk.util.misc import vtkGetDataRoot
  VTK_DATA_ROOT = vtkGetDataRoot()
  
  # Create the RenderWindow, Renderer and both Actors
  #
  ren1 = vtk.vtkRenderer()
  renWin = vtk.vtkRenderWindow()
  renWin.AddRenderer(ren1)
  iren = vtk.vtkRenderWindowInteractor()
  iren.SetRenderWindow(renWin)
  reader = vtk.vtkParticleReader()
  reader.SetFileName("" + str(VTK_DATA_ROOT) + "/Data/Particles.raw")
  reader.SetDataByteOrderToBigEndian()
  mapper = vtk.vtkPolyDataMapper()
  mapper.SetInputConnection(reader.GetOutputPort())
  mapper.SetScalarRange(4,9)
  mapper.SetPiece(1)
  mapper.SetNumberOfPieces(2)
  actor = vtk.vtkActor()
  actor.SetMapper(mapper)
  actor.GetProperty().SetPointSize(2.5)
  # Add the actors to the renderer, set the background and size
  #
  ren1.AddActor(actor)
  ren1.SetBackground(0,0,0)
  renWin.SetSize(200,200)
  # Get handles to some useful objects
  #
  iren.Initialize()
  renWin.Render()
  # prevent the tk window from showing up then start the event loop
  # --- end of script --
  