[vtkusers] vtkStripper question (maybe vtkPolyDataAlgorithm question)

[Fahlgren, Eric]

I'm missing something fundamental here.  I have a script culled from the Python/ClipCow example, boiled down to its basic pieces.  Why can't I force the stripper's output object, a vtkPolyData, to feed the STL writer (or indeed use it as input to filters or whatever)?  Why is the intermediate vtkPolyData object needed?  When I use a different object derived from vtkPolyDataAlgorithm (say a vtkCubeSource), I get the values I expect, it's just the vtkStripper that is behaving in a way I don't expect.

Thanks,
Eric


With line 20 True, the stl contains:

  solid ascii
  endsolid

With line 20 set to False, we get:

  solid ascii
   facet normal 0.70014 0.70014 0.140028
    outer loop
     vertex -0.5 0.44 0.3
     vertex -0.5 0.24 1.3
     vertex 0.24 -0.5 1.3
    endloop
   endfacet
  endsolid


     1  #!/usr/bin/env python
     2  # vim: set expandtab softtabstop=3 shiftwidth=3:
     3
     4  import vtk
     5
     6  block = vtk.vtkCubeSource()
     7  block.SetCenter((0.0, 0.0, 0.8))
     8
     9  plane = vtk.vtkPlane()
    10  plane.SetNormal(1.0,1.0,0.2)
    11
    12  cutter = vtk.vtkCutter()
    13  cutter.SetCutFunction(plane)
    14  cutter.SetInputConnection(block.GetOutputPort())
    15
    16  stripper = vtk.vtkStripper()
    17  stripper.SetInputConnection(cutter.GetOutputPort())
    18  stripper.Update()
    19
    20  if True:
    21     poly = stripper.GetOutput() # Why doesn't this work?
    22  else:
    23     poly = vtk.vtkPolyData()
    24     poly.SetPoints(stripper.GetOutput().GetPoints())
    25     poly.SetPolys (stripper.GetOutput().GetLines())
    26
    27  writer = vtk.vtkSTLWriter()
    28  writer.SetInput(poly)
    29  writer.SetFileName("outline.stl")
    30  writer.Update()