This page gives some basic details about the Raw Refraction Render Element and how it is used in compositing.
Overview
The Raw Refraction Render Element 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 will contain no information in the render element and therefore will render as black.
In comparison, the Refraction Filter is a render element that indicates varying degrees of refraction in the scene through brightness values in the image. Multiplying these two render elements together produces the Refraction Render Element.
To properly calculate the Raw Refraction 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.
Attributes
The parameters for this render element appear in the V-Ray RenderChannelColor render channels node.
Deep Output – Specifies whether to include this render element in deep images.
Color Mapping – When enabled, the Color Mapping options in the render settings are applied to the current render channel.
Consider For AA – When enabled, anti-aliasing is used where possible.
Filtering – Applies the image filter to this channel. Image filter settings are in the Image Sampler tab of the Sampler tab of the V-Ray Renderer node.
Denoise – Enables the render element's denoising, provided the V-Ray Denoiser render element is present.
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.
This render element is not supported with V-Ray GPU rendering.
Common Uses
The Raw Refraction Render Element is useful for changing the appearance of refractive elements of a complete render inside a compositing or image editing application. For this example, the Raw Refraction RE and the Refraction Filter RE are used to tint and brighten the refractive materials in the scene. See the how the render looks before and after compositing.
Underlying Compositing Equation
Raw Refraction x Refraction Filter = Refraction
Notes
- To properly calculate the refraction information in the Raw Refraction and Refraction Filter Render Elements, the Refraction Render Element 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.
- This render element is not supported with V-Ray GPU rendering.