This page provides details about the Caustics Render Element and how it is used in compositing.
Caustics is an effect that is produced when light rays are reflected or refracted by the materials within a scene, which can produce light patterns on objects in the scene. The Caustics Render Element displays these effects, which are generated with Caustics photon mapping, which is enabled from the Caustics rollout under the GI tab in the Render Settings window. This render element is useful for enhancing or toning down caustic effects in the composite.
UI Path: ||Render Settings window|| > Render Elements tab > Caustics
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.caustics.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 Caustics Render Element is useful for changing the appearance of rendered caustic effects with a compositing or image editing application. Below is an example of its use.
Original Beauty composite
Caustics Render Element
Tinted Caustics Render Element
vrayRE_Casutics + Beauty = Final Image
The Reflective Caustics and Refractive Caustics options on the GI section in the Render Settings window cause a similar effect in the final rendering, but these caustics do not show up in the Caustics Render Element.