This Subsurface Scattering shader has been adapted from Alien Swarm, with numerous revisions and tweaks. The point of the shader is to improve the lighting model, adding dispersion and interior fog effects. Due to specifics of the shader, it'll likely only be used under controlled conditions, and where it is the most rewarding. Like certain props, unusual looking creatures, and some characters. But not on every NPC in the game. In this selected showcase, the effect is exaggerated and using test values.