Invalid Geometric Normal - VraySSS2 & VrayDisplacement in 3.2

[Druski]

Hi,

We have just encountered an issue with the VRaySSS2 & VraySkinMtl in the Vray 3.2 release. When using the "Object-Base Illumination Map" mode in combination VrayDisplacement in 3D Mapping mode, we get a series of errors related to invalid geometry normal's, increased render times (From 9s to over 2mins), and a different rendered result. This mode is crucial to the look of an existing asset for production as "Raytraced" mode leads to a lot of undesirable artifacts. Without VrayDisplacement the rendered output and render times are as expected. I will start moving back through previous builds to try and find a release without the issue, however it would great to have this resolved. Please find the specific error and visual example below:

warning: Invalid Geometric normal (0 0 0) for "Non-converted. Unicode render instance name".

[vlado]

I don't really reproduce this here. I know it's a simple scene, but can you attach it? Also, which 3ds Max version are you using?

Finally, what kind of artifacts do you have with the raytraced mode? Eventually this is the only mode that will be left, so we will have to fix any issues anyways.

Best regards,
Vlado

[vlado]

Hm, I think I managed to reproduce it here. But still, I'm curious about the raytraced sss issues.

Best regards,
Vlado

[Druski]

The artifacts present in Raytraced mode seem to be related geometry intersections, and objects registering within a surface when close to the surface. There is also increased shadowing/occlusion surrounding these intersections. I will put an example together today to demonstrate.

I'll also include both scene files, we are currently using 3dsmax 2014, but I also tested in 2016 and the issue was also present.

I've had to roll all the way back to 3.05.07 to resolve the issue (which is a shame, cause I'd like to take advantage of the new light select separation), it is still present in 3.1.

[Druski]

Here is an example of the artifacts I was refering to, images and scene files attached.

[vlado]

Ok then, what you can do is ask at support@chaosgroup.com for access to the latest 3.2 stable builds; select the SSS object and the penetrating one, and in the V-Ray Object Properties dialog give them the same Raytraced SSS ID (f.e. 1, as in the attached screenshot). It should work better (or at least as good as I can make it now).

This change went it after the official builds were done.

Best regards,
Vlado