This page gives some basic details about the Refraction Render Element and how it is used in compositing.
The Refraction Render Element 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 rerender.
Any material in a scene that has a value set for its Refraction parameter will generate refraction information that can be seen in this render element. A surface with no refraction values set in its material(s) will contain no information in the render element and therefore render black.
The Refraction Render Element is a key component in the main Beauty Element and can easily be used to control the refractions in the Beauty composite.
The Refraction Render Element itself is already a composite of the vrayRE_Raw_Refraction render element multiplied by the vrayRE_Refraction_Filter render element. When finer control over refractions is needed in the composite, add these additional two channels to the output along with the vrayRE_Refraction render element channel.
UI Path: ||Render Settings window|| > Render Elements tab > Refraction
The parameters for this render element appear in the Attribute Editor under Extra V-Ray Attributes.
Enabled – When enabled, 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.refract.vrimg).
The Refraction Render Element is useful for changing the appearance of refractive elements in a rendered image, by using a compositing or image editing application. Below are a couple of examples of possible uses.
Refraction Render Element
Original Beauty Composite
Brightened Refraction Render Element
Brightened and tinted Refraction Render Element
Brightened and Tinted Refractions