[vtkusers] DecimatePro -> for surface meshes only?

[John Harris]

Hi experts,

Probably a silly question but, is vtkDecimatePro meant for surface meshes 
only?

I have a volume mesh (tetrahedra's) which I convert to traingles using 
vtkGeometryFilter, then decimate using vtkDecimatePro, then retriangulate 
using vtkDelaunay3D

I need to display just a slice, or cross-section of this, and I do this 
using vtkCutter with a defined plane

This results in "holes" through the cross-sectional slice.  If I display a 
slice without decimating and retriangulating, then I don't see holes.

So is this because I'm using a volume mesh?
Is there a way I can decimate a volume mesh successfully using VTK?

Thank you kindly..!
LD