SSS2 Problem

[simmsimaging]

I avoid SSS as much as possible as I always find it a pain to setup (RT doesn't help unfortunately) and I burn a lot of time messing around rather blindly

I've been putzing around trying to get a decent white sponge material for a project and I'm close, but now getting some odd rippling patterns in the SSS. My settings are in the screen shot, and I"m rendering with LC/BF so no IM contributing to the issue.

This is coming in as a problem as I reduce the scatter radius (i think anyway). What do I need to change to smooth this out, without getting the SSS so spread out that the whole block is whited-out?

Thanks for any tips!
/b

[vlado]

Does it happen around polygon boundaries? What happens if you increase the tessellation of the object?

Best regards,
Vlado

[simmsimaging]

Thanks Vlado
It does not seem connected to polygon boundaries - the objects was quite well subdivided (about 60K) but I turbosmoothed it to 400K and it seems the same:

[simmsimaging]

Looks like the problem is coming from using the VrayDisplacement modifier on the object. Turning that off resolves the problem:

[Morbid Angel]

are you sure its not the displacement on the mesh thats not working and not the sss?

[simmsimaging]

I'm not sure of anything actually I think this is actually a beta issue though.

[tashko.zashev]

Hi Brett,

Can you post a simple scene to test with?

[simmsimaging]

I sent a link to Vlado but will send it to you shortly as a well.

[tashko.zashev]

Hi again,

It seems that this issue persist only for the nightly builds.
We have sent your scene file to the developers, so this should be fixed soon.
Thank you for the feedback about this case and i will try to keep this thread updated.

[tashko.zashev]

Hi again Brett,

Actually this is not a bug, there are new options available for V-Ray SSS2 material in the nightly builds.
They control the sampling quality based on geometry, which means that you can control the SSS quality depending on the mesh (independent from the camera view), instead of using IRR map calculations.
Basically when "geom. based sampling" option is "ON", you can control the SSS material quality by increasing the "Samples per unit area" parameter. For your scene setup i can suggest to use value "64", for an example.
I hope this information helps you.