Separate Raytrace SSS to its own node/attribute

[sdelalla]

Hello,

We are needing to use the Raytraced SSS set feature, but want to be able to use it on its own, without bundling the primary visibility controls along with our asset. Workflow wise, SSS Sets get established in our lookdev phase, but then single object property nodes get applied to group nodes in the lighting phase, usually across multiple assets. This means we are not able to use the Raytraced SSS feature unless it becomes its own node, or we could add the feature on the shape nodes of objects. Is this possible to do?

Thank you!

[yolov]

Hello,
I'm not sure I fully understand the question. What exact feature are you referring to when you say "Raytraced SSS set feature"? Could you also explain in a bit more detail what exactly you need to achieve?

Thanks in advance

[vlado]

I think they mean the SSS Surface ID in the V-Ray object properties.

This ID is actually stored as a V-Ray user attribute and you can create it yourself on the shapes/nodes that you need it to, f.e. by adding a V-Ray user attribute called "VRay_SSS_SurfaceID" - see the attached scene.

Best regards,
Vlado

[sdelalla]

Yep that is exactly what we needed. Thanks Vlado!

[sdelalla]

Hi Guys - Unfortunately this feature seems to be working incorrectly. Please see the following four images.

I believe all images except #4 should be identical to image #1 with no SSS sets. We are getting a very weird combination of shadowing and highlights when using the attribute. The images below illustrate this pretty well, please let me know any questions:

[vlado]

This is a separate issue that occurs regardless of how the the SSS ID is specified (through the object properties or though a custom attribute). It's on my list of things to look into.

Best regards,
Vlado

[Mihail.Djurev]

Thank you for the detailed report. We managed to find the cause of the issue. We'll notify you when a fix is available for download.

[sdelalla]

Great news, thank you!

[Mihail.Djurev]

Builds 27387 and later from the 3.5 stable nightlies have the fix.

[sdelalla]

Thank you Mihail!

[sdelalla]

Hello, going to resurrect this old topic.

The use of "VRay_SSS_SurfaceID" came up again on our team recently and I realized it was not documented anywhere in the main documentation. It is a very useful feature artists to know about, and I recommend it gets added to the sub surface material sections of the docs for Fast SSS and ALSurface.

Additionally, it would be easiest if the SSS Surface ID was added to the MTLWrapper shader so it properly mirrors the Object Properties node. Currently it is missing this attribute.

Thank you!

[yolov]

Thanks for the suggestions, sdelalla we'll consider making some improvements.