
Have you ever pressed a flashlight against your fingers and noticed how light goes through them and makes them glow a warm red color? This effect is called subsurface scattering (SSS): light enters a material, scatters beneath its surface, and exits elsewhere.
The same behavior can also be observed in semi-translucent materials like wax, marble, jade, and even food. This effect is quite important in 3D rendering as it makes objects look realistic. Without it, objects may appear unnaturally flat, opaque, and plastic-like.