OTOY Forums

treddie wrote:
Thanks, Frank, for the info. It at least explains part of the improvement I see now that I moved those parts back into the 0-1 range, and painted with 50% gray. However, although the texture problems seem to have cleared up, the black triangles are still there and C4D says the normals are fine:

Displacement Woes 2 LoR.jpg

I don't know if it will help at all, but could you post a shot of the UV layout for the object? Nothing accidentally overlapping somewhere? Some polys badly stretched? While your geometry normals look good, there's obviously still some issue with the shading normals, so the UV>XYZ transform is at least suspect.

- Frank

Odd thing is, it only happens in Octane with displacement. Even Octane's object previewer doesn't have the problem. C4D renders it fine as well as Creo solid modeler.

treddie wrote:Odd thing is, it only happens in Octane with displacement. Even Octane's object previewer doesn't have the problem. C4D renders it fine as well as Creo solid modeler.

Yes, the surface with a simple solid color would look fine, since the geometry is good, even if the UV space is out of whack. Does a bump or a normal map render properly? What if you drop a simple UV layout grid into the diffuse channel? Do you see any significant distortion of the texture in the problem areas? Like I said, it's a shot in the dark, but seems like a possible culprit.

Hi treddi,
please, also check the vertical direction of your uvs, if they are flipped and pointing down, you can have weird results.
ciao Beppe

Tried the suggestion to use a bump map instead of displacement and it cleared up all of the problems:

treddie wrote:Tried the suggestion to use a bump map instead of displacement and it cleared up all of the problems:

Ah-ha! So it probably is an issue with the displacement system, not your model. You might want to pass your file on to the developers. Displacement has a number of problems I think they're working on, and while this may be a byproduct of a known bug, you never know.

Agreed.