how-to-render-a-thickness-pass-in-v-ray

In certain cases when using translucent materials or when using subsurface scattering, a valuable compositing pass or utility shader to have is one that can determine (or pseudo-determine) an approximate thickness of the interior of an object. A “thickness” render pass could describe the relative thickness as represented by greyscale values.

When setting up the shader, we will need to invert these values however, and then re-invert back in our compositing package later on

In a posting on his Materialism blog, Stuart Tozer demonstrates creating a “thickness” or “Gummi” syle shader in V-Ray using a tweak to the fog value of the standard V-Ray Material. He will also show a similar technique using mental ray and the mia_Material X shader.

As Stuart shows in the demo video, the narrower parts of the dragon, including the horns, the tongue, and the tip of the tail spar in a darker color which represent the thinner areas, while the legs, belly and head that are represented by the whiter areas are thicker.

Check out the post for Creating a ‘Gummi’ type Thickness Shader in V-Ray and Mental Ray here.