[vtkusers] Actors Vs. Memory

[Joseph Toman]

Hi,

1) Could someone tell me why the first code fragment below takes dramatically
less memory than the second? It doesn't seem like it can just be attributed
to the extra mappers and actors. 

2) Where should I look for information on how to render large
datasets, particularly those where at any given time most of the data
does not need to be displayed?
				 Thanks,
						J. Toman

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ren = vtkRenderer()

append = vtkAppendPolyData()

for k in range(0, 20):
   for i in range(0,20):
      for j in range(0, 20):
         cube = vtkCubeSource()
         cube.SetCenter(2*i, 2*j, 2*k)
         append.AddInput(cube.GetOutput())

polymap = vtkPolyDataMapper()
polymap.SetInput(append.GetOutput())
actor = vtkLODActor()
actor.SetMapper(polymap)
ren.AddActor(actor)


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ren = vtkRenderer()

for k in range(0, 20):
   for i in range(0,20):
      for j in range(0, 20):
         cube = vtkCubeSource()
         cube.SetCenter(2*i, 2*j, 2*k)
	 polymap = vtkPolyDataMapper()
	 polymap.SetInput(cube.GetOutput())
	 actor = vtkLODActor()
	 actor.SetMapper(polymap)
	 ren.AddActor(actor)