The Refraction Filter Render Element is an image that stores refraction information calculated from the materialsrefraction 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 V-Ray 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 V-Ray Refraction Render Element.

To properly calculate the 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.

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

Refraction Render Element

Original Beauty Composite

Refraction Filter Render Element

Brightened Refractions

Tinted Refractions

Compositing Formula

The Refraction Filter Render Element 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.

V-Ray Raw Refraction x V-Ray Refraction Filter = V-Ray Refraction