The implementation of subsurface scattering in Carrara is real sub-surface scattering. As far as I know it is state-of-the-art. It is not a simple absorbtion calculation at all. Of course it is only an approximation like every 3D rendering but that is exactly what 3D rendering is, a simulation... As far as I know the model is used is quite accurate and can be used at a decent speed. Full Monte Carlo integration of subsurface scattering was the old way to do subsurface scattering before more advanced technics appeared. It usually gives the same result (basically you won't see the difference in 99.9% of the cases) and is much much slower (if you like to wait a day for a rendering...). It does assume that the object does not contain another object inside it which is a limitation but from what I have seen a lot of the other implementations have the same limitation. Charles