When light passes through the surface of water, it is diverted and concentrates at bright spots and stripes at the ground. This effect is simulated by the Caustics function. You can use it to create animated underwater textures.

The number of wave centers can be controlled by the Count parameter. Increase this value to create more chaotic caustics patterns. The Size attribute defines the wave length. Decreasing this value whirls up the water, too.

The height of the waves is set by the Amplify value. Decreasing this value creates softer caustics.

With the Bias value you can change the distance of the water surface to the ground. Use this value to switch between flat and deep water.

Random Seed is used to vary the position of the wave centers. Each value produces an unique pattern.

The Time Offset parameter is important for creating animated textures. Increase it to make the waves move on. After 1000 time frames the pattern will repeat.

Disable Auto Change Seed when experimenting with the Time Offset value.

Tip: Use the Animation Recorder at the Tools menu to easily record animated caustics.