[vtkusers] Hardware Clipping planes

[Dimitris Agrafiotis]

Dear All

I have a polygonal object which I want to clip using hardware clipping 
planes. However I want to keep the part of the object that is outside 
the region defined by the 6 clipping planes and not the inside, thus 
leaving something like a hole in the geometry. To do that I currently 
use 6 mappers defining a clipping plane for each one (with the normal 
of each plane looking outwards). To avoid re-rendering parts that 
already exist from previous mappers I also include the clipping planes 
used so far(minus one) with the normals inverted. 

I am wondering, is there any smarter way to do that? What about using 
the stencil buffer to define pixels that shouldn't be drawn? Can I 
manipulate the stencil buffer with VTK? Or is this wrong anyway?

Thanks in advance

----------------------
Dimitris Agrafiotis
University of Bristol
Department of Electrical & Electronic Engineering
Merchant Venturers Building 
Woodland Road, Bristol BS8 1UB, UK
Phone:  (+ 44 117) 9545194
E-mail: d.agrafiotis at bristol.ac.uk