Vray warning explanation

[fixeighted]

I'm getting a warning saying: Invalid geometric normal (0 0 0) for ''Non-converted Unicode render instance name''

I isolated the cause as a vray displacement mod on a piece of geometry with a tessellate mod on it also. If I disable the tessellation or displacement then it's fine.
It doesn't seem to actually cause any obvious problem and the displacement still works, so just thought I'd flag it. I've used the exact same approach before and not seen this error.
Please let me know if it's a known thing and whether I'll run into any problems continuing. I'm on 2020 and the latest Vray.

[fixeighted]

Hmm, nobody has an explanation for this? Just curious
EDIT: Oops, sorry, I forgot it's the weekend....I lose track of time. Please ignore until normal working hours

[glorybound]

Yep, I get it too.

[fixeighted]

Maybe it's a false positive, as nobody else has any idea...

[yavor.rubenov]

Hello,

Do you have any hair in that scene with VRayHairNextMtl on it ?

Best regards,
Yavor

[fixeighted]

No, the only displacement is on a wall and no hair mtl anywhere.
Maybe it's the tessellation modifier?

[Philip Shounev]

Could you send over a scene to philip.shounev@chaosgroup.com, since I couldn't replicate the issue on my end?

[fixeighted]

It is certainly odd and I think it's some sort of specific geometry issue, after testing. Here's a file, as I just cannot work it out. As I mentioned, the error does not prevent the displacement.
https://www.dropbox.com/s/0qdmcm235d...0MESH.max?dl=0
https://www.dropbox.com/s/6xlx646394...0BUMP.jpg?dl=0

glorybound Can you share a piece which also exhibits this behaviour? It would be interesting to see if there are similarities.

EDIT: I found what was causing the error but cannot explain why. After detaching just the indicated polys the error stops. Very weird and I guess there's no possible way of predicting this behaviour.

[fixeighted]

Glitchiness

[Philip Shounev]

Thanks for providing a sample of your scene. Indeed there seems to be an issue here when using displacement and subdivided geometry, for which I've informed our developers to investigate what would be the cause for those warnings (issue ID:VMAX-9485). As a workaround you could use 2D displacement type with some shift adjustments.

Best regards,
Philip

[fixeighted]

Thanks for looking, although please see the edit I posted. Also as I mentioned, although the error comes up it doesn't actually affect the displacement at all. At least, not in any way I could discern.
My test, with the detached piece, was done after collapsing the tessellated mesh, so only the displacement mod was active.
Why it should go away just by deleting a few polygons is also a bit weird.