[vtkusers] Cutting a polydata using a concave set of planes

[Pietro Cerutti]

Hi,

I'm trying to figure out how to cut a polydata using a set of concave
planes.

Say, I have a cube, and I want to clip away the upper quarter, which is
defined by a pyramid whose tip is in the center of the cube and the base
is the upper face.

Let's have this cube centered at (0, 0, 0). I have two planes:
1) at (0, 0, 0), normal (1, -1, 0) --> cut away the upper left half
2) at (0, 0, 0), normal (-1, -1, 9) --> cut away the upper right half

I have tried to use vtkImplicitBoolean to combine these two planes, but

- Intersection results in the whole cube (nothing is cut away)
- Union results in nothing (the whole cube is cut away)

I attach to this email a tarball of this sample project, including two
screenshots of the results clipping with plane 1) and plane 2).
The tarball is also available at this address:

http://people.freebsd.org/~gahr/vtk_concave.tar.bz2

Thanks for any insight!

-- 
Pietro Cerutti
gahr at gahr.ch

PGP Public Key:
http://gahr.ch/pgp
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