[vtkusers] different front/back-color of a vtkQuad

[Jens]

Hi,
I just realized, that the subject of my last mail was hard to
understand, sorry. So here we go with a second try.

The question is still the same:

I would like to visualise boundaries in 3D. For that purpose I use vtkQuads.
Now I would like to color these vtkQuads that way, that the user can see
if he is looking at the front or at the back of the quad.

Does anyone knows how to color the front of a quad in a different color
than the back? Is that possible with vtk?

Greetings
Jens