Caustics are light patterns that are created when light has been refracted by one or more surfaces. Only mobiles can produce caustics in Awakening.
To render caustics, follow these steps:

1. Create a Material with the Generate Caustic checked beforehand, set a proper Refraction Index for it: . You must set it's Alpha component to a diffuse color less than 255, to create transparency.

2. Assign this Material to a mobile.

3. Create a light and check it's Generate Caustic property:. The Detail option controls the 
lights emission-density for caustics.

4. Press F8 to render the caustics. You can render caustics for specific mobiles or lights by 
selecting them before rendering.

Refraction Indexes of familiar materials:

 Material  Refraction Index
 Vacuum  1.00000
 Air  1.00029
 Alcohols  1.32900
 Crown Glass  1.53000
 Crystal  2.00000
 Diamond  2.41700
 Emerald  1.57000
 Fused Quartz  1.46000
 Heavy Flint Glass  1.65000
 Glass  1.50000
 Ice  1.30900
 Quartz  1.64400
 Ruby/Sapphire  1.77000
 Salt  1.54400
 Sugar Solution (80%)  1.49000
 Sugar Solution (30%)  1.38000
 Topaz  1.61000
 Water  1.33333