[vtkusers] vtkDecimatePro question

[Brian Webb]

I'm trying to use vtkDecimatePro to decimate a model, and it appears to be
just removing facets and leaving holes in the model.  According to the
documentation it appears that calling PreserveTopologyOn should prevent this
from happening.  This works with a standard (fran) model, but it doesn't on
my models.

I'm thinking that there's something inconsistent in my models (the normals
are inconsistent, or the polygons are not ordered correctly), but I can't
figure out a way to correct it.  I tried vtkPolyDataNormals, but that didn't
work.

Any ideas on what else I could try would be appreciated.  I've included the
relevant parts of my script at the end of this email.

Thanks,

Brian Webb

#
# Read the model.
#
vtkOBJReader importer
  importer SetFileName mig27.obj
#vtkPolyDataReader importer
#  importer SetFileName "$VTK_DATA_ROOT/Data/fran_cut.vtk"

vtkTriangleFilter triangs
  triangs SetInput [importer GetOutput]

vtkPolyDataNormals normals
  normals SetInput [triangs GetOutput]
  normals FlipNormalsOn
  normals SplittingOff
  normals ConsistencyOn
  normals ComputePointNormalsOn
  normals ComputeCellNormalsOn

vtkDecimatePro mesh
  mesh SetInput [triangs GetOutput]
  mesh SetTargetReduction 0.7
  mesh PreserveTopologyOn
  mesh AccumulateErrorOn
  mesh SplittingOff
  mesh DebugOn

#
# Create the mapper.
#
vtkPolyDataMapper mapper
mapper SetInput [mesh GetOutput]