> Now the question.
> Can Povray use a algorithm like this:
>
> http://graphics.ucsd.edu/~henrik/papers/bssrdf/
>
> or, more generally, exist a skin shader for Povray??
>
Well, this depend on what you want. Just in practice, subsurface scattering
(interior, volume effect...) cost some extra rendering time, everywhere. In
case of human head, it's hard to avoid artfacts, like interactions with
teeths or eyes, or overlapped surfaces (which is very hard to avoid with
animated lips, if you like your character to talk), etc.
I used skin shader from POVMan release, before few years, it was good,
somewhat slower than standard POV materials.

There is a good article of 'usable' human skin shading at
http://www.optidigit.com/stevens/shadetut.html . Human models on the rest of
this site looks very realistic. This is for Maya, but main principle is well
explained: some colors of skin depends by angle of incidence, light-shadow
or angle to camera. Say that ambient color and highlights are most
important. In this way, it's easy to get something very similar with
mentioned example, with rendering speed 'as usually'.
Almost all commercial 3d support this, even hardware accelerated rendering.
I founded one very similar shader for human skin, based on AOI, in nVidia
CG Toolkit.
In POV-Ray area, AOI (angle of incidence) is supported only by MLPOV,
http://pov.monde.free.fr/mael/mlpov083.html , as far as I know.

Anto

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