ALsurface shader sss question

[DHX KBuckley]

I'm using the ALSurface shader for character skin, however since the ears and nose of the character aren't sewn into the head I get a grey AO shadow at the connection point. To get around this I have added a vray object properties node and turned the 'SSS surface ID' value to 1 and this gets rid of the grey AO in the skin. My supervisor has asked me to find out if there is another way to do this in VRay so that we don't burden the lighting team with more complexity when setting up their layers. Can anyone tell me if there is a way to treat separate meshes as a contiguous object when using ALSurface SSS without using a VRay Object Properties node? I searched the available attributes but nothing seemed appropriate.

I'm attaching an image of a simple test object that I've been using for this issue.

Thank you..

[Morbid Angel]

I think if you attached the geometry it will also render properly.

[DHX KBuckley]

Not really an option to sew in the ears and nose.. The model in the image is just a simple test proxy of the real show asset and both versions need to have ears, nose and eyes that can slide around the model for extreme anim poses.

[Morbid Angel]

Yeah I meant just attach them as meshes, not really sew them / blend them as single geometry. In that case you can still rig it to move around. Its not ideal but perhaps its better solution. Also, carrying an object properties node is something we do all the time so it may not be that bad to use that, its non destructive also.

[DHX KBuckley]

Yeah! That does the trick.. Thank you Dmitry.

[Morbid Angel]

Vlado I wonder if sss surface ID can be added as a shape attribute rather then vray object property node? In that case any shapes which have same sss surface id will be treated as such. I think this would be ideal solution for cases like this.

[DHX KBuckley]

I initially looked for an attribute to do this but was unable to find anything.

[yolov]

I'll add a note to also make it available as an attribute, it does make sense to have it this way.

[DHX KBuckley]

That would be great, thank you..

[vlado]

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

[DHX KBuckley]

Thank you I'll take a look a bit later when (if) can find some time. cheers!

[DHX KBuckley]

I finally had some time to test your scene file and that worked like a charm.. Thank you Vlado! Just wondering if there's a way to employ a similar strategy regarding Xgen shadow casting? I tried to add a Vray user attribute to some Xgen descriptions and then turn shadow casting to a value of zero but that didn't work. Any Idea how I can turn off Xgen shadow casting without using a VOP?