OceanThe Ocean shader simulates realistic waves over a large body of water. The artist can control the look and feel of the ocean by adjusting the waves' height, roughness, speed, direction, etc. Ocean can even create a looping animation, with the number of frames in the loop specified by the user.
Create a large grid.
In the texture dialogue box, select Ocean as the texture shader.
Assign a dummy image to the texture.
Edit Ocean's parameters.
The Wave Size box controls the waves' basic size and shape. Largest sets the size of the largest waves in the ocean, Smallest sets the size of the smallest waves in the ocean, while Number Between sets how many wave sizes are between Largest and Smallest. Increasing Number Between will give a rougher look to the ocean.
Steepness gives another control on the roughness of the ocean: smaller values of Steepness will give a calm, flatter ocean, while larger values give a rougher, more active ocean.
Wave positions can be relative to World Center, so that two adjoining grids wave patterns will be aligned; or Object Center, so that as the object moves, the wave patterns will move with it.
Direction controls the overall movement of the waves; either a Directionless choppy ocean, or a Directed rolling-waves ocean.
For animation, two controls are available. Wave Speed controls the movement rate of the waves. The default value of 1 is a good choice for a scene where one SoftImage unit is equivalent to one foot, and where the animation is at 30 fps.
Loop Animation will force the ocean into a looping animation. Frames controls the number of frames in the loop. Be warned, smaller numbers create a less realistic ocean.
Ocean creates its effect in one of two ways. As a Bump, Ocean creates the illusion of a rough surface without actually changing the geometry, similar to a bump map. Note that Ocean's bumping effect is independent of the texture settings, so the Roughness parameter in the texture dialogue box should be set to 0.
Ocean is usually best kept in Bump mode, since it gives a very nice wave effect without requiring additional geometry, and therefore does not inordinately slow down rendering times.
In Displacement mode, Ocean creates a greyscale image for the shape of the ocean, with which it displaces the actual geometry of the water grid, using the displacement feature of mental ray. When using Displacement, the Displacement parameter in the texture dialogue box should be enabled, and the roughness should be set to 1.
As with all displacement mapping, the object in question must have enough geometry in order to properly resolve the shape of the displacement map; this usually results in extremely slowed rendering times. If you wish to use displacement, a good compromise can be achieved by using Ocean twice: once as a Bump for smaller waves, and once as a Displacement for larger waves.
Real oceans or lakes have differing areas of roughness: some regions can be fairly smooth, while other areas are rough, the variations caused by the effects of gusting winds. The Flats effect simulates these differing areas. Size controls the size of the area, while Variation controls how different the areas can be: lower values cause less variation, higher values cause greater variation.