A crucial aspect of realistically modelling the interactions between light and participating media is subsurface scattering. This process takes into account the subsurface characteristics of absorbed light, with respect to the microfaceted absorptive and reflective properties of a material. The most recognizable visual result of this process is translucency.
This experiment sought to approximate this effect in real-time on a GPU using a number of simplifications. The result is an effect that can be used to simulate the appearance of subsurface scattering in a game.
Check out my related blog post for more information about how this effect is implemented.