The Refraction Render Channel stores refraction information calculated from materials – such as glass or water – that refract objects behind them in the camera's view. This means the brightness, coloration, etc., of the refractions can be adjusted without the need to re-render.
Any material in a scene with a value set for its Refraction parameter generates refraction information that can be seen in this render channel. A surface with no refraction values set in its material(s) contains no information in the render channel and, therefore, renders black.
The Refraction Render Channel is a key component in the mainBeauty render and can easily be used to control the refractions in the Beauty composite.
The Refraction Render Channel itself is already a composite of theV-Ray Raw Refraction Render Channelmultiplied by theV-Ray Refraction Filter Render Channel. When finer control over refractions is needed in the composite, add these additional two channels to the output along with theV-Ray Refraction Render Channel.
