Table of Contents

This page gives some basic details about the Refraction Filter Color Channel and how it is used in compositing.

 

Overview

The Refraction Filter channel is an image that stores refraction information calculated from the materials' refraction values in the scene. Materials with no refraction values appear as black, while refractive materials appear as white (maximum refraction) or gray (lesser amounts of refraction). If any hue (color) is specified in the material's Refractive Color parameter, that hue and value will be represented here in the Refraction Filter as well as being affected by the refraction's Amount parameter.

In comparison, the Raw Refraction Render Element is a color render element that takes materials and their colors into account when rendering refraction. Multiplying these two render elements together produces the Refraction Render Channel.

 

 

UI Path

||Node Editor|| > Add > Render Channels > Color Channel > Type > Refraction Filter



Common Uses

The Refraction Filter is useful for changing the appearance of refractive elements after rendering, using a compositing or image editing application. Below are examples of possible uses.

 

 

Refraction Filter Render Element

Original Beauty Composite

Refraction Filter Render Element with added contrast

Tinted Refraction Filter Render Element with added contrast

Refractions with added contrast

Tinted Refractions with added contrast

 

 

Underlying Compositing Equation

The Refraction Filter is multiplied by the Raw Refraction to produce the same information seen in the Refraction pass, but having them separated out allows them to be manipulated individually before combining them together. 


Raw Refraction x Refraction Filter = Refraction

 

 

 

Notes

  • To properly calculate the refraction information in the Refraction Filter and Raw Refraction, the Refraction Render Channel must also be rendered at the same time, even if it's not going to be used in the compositing process. Doing so enables all the refraction information to be included in the rendering calculations.