Understanding SSS

[vicnaum]

Hello to the community!

Here's an interesting research of measuring real-world scattering/absorption values:
http://vision.seas.harvard.edu/inverse/




And it has this kind of data in PDF:



The worth of this data is clear, because it's very hard to distinguish realistic values for SSS/Absorption by hand, so it's handy to have something to start with (some "presets" available).

So what I ask for:
Could please someone explain the internal mechanics of Corona values, and how can I convert the provided measured mm^-1 data to corona Absorption/Scattering RGB color + Distance in mm. And Directionality also (but I completely don't understand how to convert their phase functions into directionality)
(First Sigma S is for scattering, second Sigma alpha - is for absorption, in R/G/B, 1/mm values)

[Ondra]

we will first finalize the implementation, during which the mapping of parameters can change, then we will provide the equations, or directly provide presets.

[vicnaum]

Great, thanks

[zzubnik]

we will first finalize the implementation, during which the mapping of parameters can change, then we will provide the equations, or directly provide presets.

Presets are awesome, speeding up material creation hugely. I wish you'd reconsider having basic presets in the main Corona material too (clay, mirror, glass, plastic, etc as with A&D and iRay materials) as these make texturing large scenes so much quicker.  My ideal renderer would have the ability to add, remove and alter presets.

Can't wait to play with SSS.

[vicnaum]

Any updates on this?

[Noah45]

3rd party presets welcome, also and always!