Caustic
Updated: 11/26/2018 by Computer Hope

A caustic is a mathematical curve which defines the way light passes through a curved material surface. In CGI (Computer-Generated Imagery), caustics are calculated as mathematical curves by ray tracers to create photorealistic images of translucent curved surfaces.
For example, the light passing through a wine glass can be defined by a caustic.
Caustics may also be dynamic, for example, to define the rippling effect of light that passes through a surface of water.