[vtkusers] Removing duplicate points from unstructured grid / polygonal data

[Mark Asbach]

Hi list,

I've got a problem that I didn't find a simple solution for (though it 
might be obvious to those of you that are more familiar with vtk than I 
am).

When two different parts of - lets say a CAD model - are represented as 
unstructured grids, their surfaces are extracted with a 
vtkGeometryFilter and then merged with vtkAppendPolyData, "internal 
surfaces" remain. I mean, those two parts might overlap or just contain 
the same points (meaning, points with different point IDs but the same 
coordinates). How can I eliminate doubled points or internal surfaces?

Think of two some-elements-thick halfs of an eggshell. If put together, 
there'll be an inner surface an a lot of doubled points at the "rim" 
that I want to remove.

Thanks in advance,

Mark