Subsurface Scattering - in practice?

[Kaotik]

I just thought of something, when people say how World of Warcraft's graphics engine is behind it's times.
Yet it's the only game which I can figure out that even TRIES to do some sort of subsurface scattering -like effect.
etc, even Night Elven ears IIRC.One of the best places to notice this is during nights flying for example on a gryphon, and changing the view so that moon is behind the gryphon (looking bit from underneath) - the wings "thinner part which is "just feathers"" clearly lets some of the light pass. Same goes for capes/cloaks etc

Of course I do realize this is far from what "real subsurface scattering" would be, but is this the only real step anyone has taken towards it?

Is it extremely heavy for the hardware, hard to implement or.... ?

 

[Graham]

It is probably texture based, pre-done by the artists. A really easy way to do it would be where the 'transparency' texture colour gets modulated with the lighting value of the pixel if it's normal were flipped.

There is a sample in the directX sdk (here ) that does something similar, although it takes it one step further by actually using precomupted radience transfer to caclualate the light value before being modulated with the transparency texture. Personally I don't really like PRT though, it is one of those techniques I feel will never really catch on as it simply requires stupendous amounts of precomputed data to look any good...

It's not really that hard an effect to fake, just requires more work from the artists. Actually simulating it is the tricky bit, or in the case of the DX sample, half simulating it, half faking it.

 

[SugarCoat]

ATI did a demo at the X800 launch, i found it to be the best one personally; if i were demo picking that is:


MPEG: http://www.ati.com/online/radeonx800/subsurface2.html
QUICKTIME: http://www.ati.com/online/radeonx800/subsurface3.html

Have to agree its problably too complex to impliment in wide scale. Neat visual though.