9.5.2
36 • CAUSTICS
CAUSTICS • 37
Figure 2: The metal ring shows a caustics effect generated by a reective surface.
Figure 3: The bright “tail” extending from the sphere is a volume caustics effect.
Advanced Render enables you to create both surface caustics and volume caustics.
A surface caustics effect shows up on object surfaces only — examples are the
transparent sphere and the ring (in both cases, the effect shows up on a surface: the
oor).
Volume caustics are visible as they pass through 3D space — they do not need a
surface to illuminate. See Figure 3.
The surface caustics algorithm
For surface caustics, you need:
A light source that emits photons — enable surface caustics (in the Attribute manager,
on the light’s Caustics page);
An object with a material that generates surface caustics — the material must be
transparent or reective or both. The object must be curved in a way that focuses
light;
An object to receive the surface caustics.