Renderman's upcoming SSS Shader

[stevejjd]

Hi all
I just saw this article https://www.fxguide.com/featured/pix...graph-preview/

What do you guys think?

Can V-Ray do the same

1. Brute force path tracing (albedo inversion)
2. Non-exponential brute force path tracing.

Will Chaos group be developing any new skin shaders?
How does ALSurface compare to the new Pixar one?

Steve ~

[vlado]

You've already had that for a while in the form of the VRayScatterVolume material.

Best regards,
Vlado

[stevejjd]

Thanks Vlado Ill just stick with ALSurface for now.

[^Lele^]

"Everything comes with complications. One of the reason that these new methods are better is that they do not assume a semi infinite one sided piece of skin. But this means that the interior (or inside) modelling of the face now matters more. Teeth and bone modeling become important, and also by the same logic, surfaces need to be closed."

It's not just volumeScatter being difficult to set up, you see, either.
And it too would be a LOT quicker if properly set up, and extinguishing the right way: ie. a dominant hue, proper absorption in the medium, and so on would make it quicker than when it's used for general scattering of thin mediums (where paths get MUCH longer as extinction of energy is slow.).
That benefit is however negated when the scatter paths lengthen and concentrate to create those "glowing" areas we all like, and hence the overall speed doesn't really come into play all that much (see their 10% average estimate.).

see below:
Left, VrayScatterVolume, default colors, adjusted radius (identical in both shaders, roughly 3/4 of the torus diameter.), and phase (0.25, or forward into the medium, away from the light).
Center and right, a more extinguishing setting (lowered colors values), without and with internal geo (simulating bone, or cartilage).
The SampleRate SR has been captured early on to show what i meant by "path length": notice how the "standard" settings get sampled everywhere, but will eventually converge faster than the "bouncy" areas of the more absorbing shader, which however converges very very quickly everywhere else (see the second SR RE, captured later on.).
It's all out of scale, so nothing looks like it should (and surely not skin), but it ought to prove the point i was making.