Global illumination and caustic effects are handled in a very similar way. The workflow for each effect is nearly identical, but the results can be stunningly different.
The light energy for both the global illumination and caustic effects are measured in photons. There is a wide range of photon controls that allow you to fine-tune a photon effect in either the render region or the final render pass.
Prepare the scene — Apply materials and surfaces to objects and ensure their settings enhance the photon effect. For information, see Preparing Object Surfaces.
Define an emitter — Create a light in your scene that emits photons for either a caustic or global illumination effect. For information on designating a light as a photon emitter, see Defining a Light as a Photon Emitter.
Define the casters — Select an object in your scene that transmits the photons (such as a lamp or the sun). For information on defining a caster, see Setting Photon Casting, Receiving and Visibility.
Define the receivers — Select an object in your scene that receives the photons (such as a desk or water surface). For information on designating a receiver, see Setting Photon Casting, Receiving and Visibility.
Display the photons — Set up your render region and/or render pass settings to display global illumination and/or caustic effects. For information on setting your render options, see Displaying Photons in the Render Region and Preparing Global Illumination and Caustics for Rendering.
Adjust the photons — Set and tweak the number of photons, their intensity, and their accuracy so they are as strong or subtle as you wish. For information, see Preparing Global Illumination and Caustics for Rendering.
Regions