This page provides information about the Raw Refraction Filter Color Channel in V-Ray for Houdini.
Overview
The Raw Refraction Filter Color Channel is similar to the Refraction Filter Color Channel, except it is not affected by Fresnel falloff. The result is a solid mask showing the areas of refraction.
To properly calculate the Raw Refraction Filter Render Element, the Refraction Render Element must also be added to the list of render elements being calculated during the rendering process to properly determine all the refraction information in the scene.
Usage Examples
The Raw Refraction Filter Color Channel is useful when a precise mask is needed for refractive objects. Unlike the Refraction Filter Color Channel, there is no need to clip or readjust values when pure black or white is required for the composite.