Note:
You can render Caustics only with the mental ray for Maya renderer.
Caustics are light effects that caused by specularly (as opposed to diffusely) reflected or refracted light.
- Refracted caustics happen when specularly transmitted light bends through a transparent or semi-transparent object or volume onto a diffuse surface.
- Reflected caustics happen when specularly reflected light bends through a transparent or semi-transparent object or volume onto a diffuse surface. Note:
In the natural world, caustics are actually a form of global illumination, but they are treated separately by mental ray for Maya, making it easier for you to control them.