Here are my replys to your post on the maya listserve..
Duncan
When you create a Maya ocean there is an "attach to camera" option. If this is on it creates an expression that resizes the ocean plane based on the camera view. It tries to keep the size of a triangle in screenspace roughly constant, so you can zoom out as far as desired, or zoom right in close at any point on the ocean without needing a huge number of triangles. Note that if you zoom out from the ocean you should make sure to have a high numFrequencies and a large wavelength max. If you don't have any large wave frequencies or too few waves the waves may look too regular. (more frequencies takes longer to render which is why the default is on the low side)
You can create any number of fluid wakes positioned over the ocean, and they may overlap and be different resolution. As the ocean scales down when one zooms in the triangle resolution will increase to better resolve the displacements on the small ripples.
There are a variety of methods for getting black and white render of the displacement, depending on what is desired. The fluid wakes are textures that are applied as a map on the ocean shader's waveHeightOffset. These textures can also be applied instead as color texture maps... just assign a black lambert shader to the ocean and connect the wake texture's outAlpha to the lambert's incandescenceR,G+B. (the out color could be used, but you would then need to configure the color attribute on the fluid texture correctly.. fluid textures have outColors that can be completely independant of the outAlpha).
If you are interested in B+W images of ocean waves, instead of the fluid wake, then there is also an ocean texture( the same texture is internally used by the ocean shader ).
An fast trick to get the ocean shader to render height as greyscale is as follows:
1. Make the environment ramp black and the specularity 0.
2. Make translucence 1, diffuse 0, and the water color white. Also make foam emission 0.
3. Make troughShadowing 1.0 (this darkens based on wave depth)
This should now shade such that the max possible waveheight is white and the minimum black, as long as you have one white light with an intensity of 1.
The multiple wakes is a bit more complicated than simply creating new ones. Also the method that comes to mind will cause the wakes to not appear on the ocean preview plane(one could write a mel script that would do temporary hookups for preview, however).
After creating a wake, disconnect it from the ocean(i.e. the connection to the waveHeightOffset). Now it will create a new wake when you use the make wake menu. Disconnect each new wake after creating.
Now create a plusMinusAverage node(set to "sum"... waveforms sum). Connect the outAlpha from all your wakes into its input1D array:
connectAttr OceanWakeTexture1.outAlpha plusMinusAverage1.input1D[0]; connectAttr OceanWakeTexture2.outAlpha plusMinusAverage1.input1D[1]; connectAttr OceanWakeTexture3.outAlpha plusMinusAverage1.input1D[2]; ..etc
Now connect the plusMinusAverage to the waveHeightOffset on your ocean shader:
connectAttr -f plusMinusAverage1.output1D oceanShader1.waveHeightOffset
The wakes should all now render, but will not show up on the ocean preview plane.
However one can still see the wakes by setting "Shaded Display" on the fluid textures to "as render".
If you need to see the exact wave height at a frame you could do convert->displacement to poly on the ocean surface(deleting the mesh generated when done).
Duncan