When light refracts through or reflects off of a surface, these bent rays are focused together, creating a bright pattern referred to as a caustic.

Refractive Caustic Reflective Caustic
The light refracts through the wine glass. The light reflects off the gold ring.
In addition to reflective and refractive, SOLIDWORKS supports indirect caustics:
  • Indirect refractive caustics are always on in SOLIDWORKS.
  • Indirect reflective caustics are always off in SOLIDWORKS.