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 main Beauty render and can easily be used to control the refractions in the Beauty composite.

The Refraction Render Channel itself is already a composite of the V-Ray Raw Refraction Render Channel multiplied by the V-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 the V-Ray Refraction Render Channel.

UI Path: ||V-Ray Node Editor|| > World > Render Channels > Beauty > V-Ray Refraction

See the Render Channels page to find out where you can find these properties.

Channel Name – Customizable name for the render channel.

Enable Deep Output – Specifies whether to include this render channel in deep images.

Color Mapping – 

Consider For Anti-Aliasing – When enabled, anti-aliasing is used where possible.

Filtering –  Applies an image filter to this channel.

Vfb Color Corrections – Applies the post-render color adjustments made from the VFB.

Denoise – Enables the render channel's denoising, provided the Denoiser is enabled.