warning: Invalid surface normal (0 0 0) for "object", using geometric normal.
warning: Invalid texture derivatives (UVW 1.#QNAN, UVW 1.#QNAN, UVW 1.#QNAN).
I’m getting these warnings with one object in my scene and I haven’t been able to find any threads on the board referring to either one. Can someone tell me what kind of problem this indicates? I’ve made sure that I have defined UVW coordinates for all the faces of the object, but that hasn’t solved it…
Thanks!
Shaun
p.s., I just upgraded to 1.47.02 -- shame on me for not including my version in the first post!
a normal of 0 0 0 seems to imply a polygon that doesn’t have any surface area…
mabye throw a STL check on the ‘object’ and see what pops out.
They mean what they say 
In the first case, VRay encountered an interpolated normal that has zero length. This can happen because of the way 3dsmax calculates surface normals. This was a cause for some shading errors (red dots etc) in previous versions. You should try to inspect the buggy mesh - welding vertices that are too close together may help.
The second error is probably related to the first.
Best regards,
Vlado
Much obliged, I welded the surfaces together and redid my UVWs… somewhere in there the problem went away. Thanks for the info!
Shaun
Yes, it is always a good idea to select all your vertices at the end and click Weld Poly with 0.1 thresh so you can have a clean mesh at the end.
I am getting similar warnings: how do I determine exactly which mesh has a problem (my scene is many many thousand meshes!)?
The warning says which object caused the problem (in the example above, the name is “object”).
Best regards,
Vlado