The Raw Refraction Render Channel is a color image that stores refraction information calculated from materials' refraction values in the scene. Surfaces with no refraction values set in their materials contain no information in the render channel and, therefore, render black.

In comparison, the Refraction Filter render channel is a render channel that indicates varying degrees of refraction in the scene through brightness values in the image. Multiplying these two render channels together produces the Refraction render channel.

Note: To properly calculate the Raw Refraction Render channel, the Refraction render channel must also be added to the list of render channels so that all the refraction information in the scene can be determined.

UI Path: ||V-Ray Node Editor|| > World > Render Channels >Raw > V-Ray Raw 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.

Derive Raw Channels – Generates data in the raw channels by combining the respective color and the filter color channels.

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.