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font-size: 12px;" lang="x-unicode">Hi,
<br>
<br>
I have a problem with shading in VTK 6.2 when using OpenGL2. The
problem is visible when using lightkit, but not with simple scene
light. I have attached pictures that demonstrate the problem.
<br>
<br>
- model.jpg shows the 3D surface I am looking at - three combined
gaussians.
<br>
- shading_flat.jpg and shading_gouraud.jpg show a view from below
at a place in the shadows, with steep surface slope. Both pictures
are taken at the same camera position.
<br>
<br>
shading_flat.jpg shows a strange patch that seems to me is a
shading artifact. In contrast, shading_gouraud.jpg shows a nice,
smooth gradient in the shadows. I have tested my code using vtk
6.1 and the result is different, i.e., similar to that shown in
shading_gouraud.jpg.
<br>
<br>
It seems also that the artifact is not there (or not visible) when
lightkit is switched off.
I have played around and I think it is caused by the fill light in
the lightkit. Depending on the position of the fill light I can
make this artifact patch all black.<br>
<br>
Could this be a bug related to the new OpenGL2 rendering engine?<br>
<br>
Thanks,
<br>
<br>
Marcin<br>
<br>
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