[vtkusers] how to check normals

[Mathieu Malaterre]

Hi,
  I have been writing my own subdividing filter. It works fine except
that the normals are not all pointing outside.
  When I render my polydata I see black triangles, that means I put my
triangle the wrong sense. But sometime the color is fine, but the
gradation is wrong....

  I tried differents permutations, but I never find the good one. Does
anyone has a clue (even a small one) ?

mathieu

--
Malaterre, Mathieu
The John P. Robarts Research Institute
Imaging Research Laboratories
http://www.imaging.robarts.ca/~mmalat