This page gives some basic details about the Raw Refraction Render Element and how it is used in compositing.
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 Render Element (vrayRE_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 (vrayRE_Refraction) .
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.
UI Path: ||Render Settings window|| > Render Elements tab > Raw Refraction
The parameters for this render element appear in the Attribute Editor under Extra V-Ray Attributes.
Enabled – When checked, the render element appears in the V-Ray Virtual Frame Buffer.
Deep output – Specifies whether to include this render element in deep images.
Filename suffix – The text added to the end of the rendered file, when saved as a separate file (e.g. myrender.rawRefraction.vrimg).
Apply color mapping – Applies the color mapping options specified in the Color mapping rollout of the V-Ray tab in the Render Setup window to this render element. This option is enabled by default.
The Raw Refraction 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.
Raw Refraction Render Element
Original Beauty Composite
Raw Refraction Render Element with added contrast
Tinted Raw Refraction Render Element with added contrast
Refractions with more contrast
Tinted Refractions with more contrast
Underlying Compositing Equation
- 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.