I have no idea what the problem is... but for some reason I just can't seem to get Maya 8 to work the way I remember Maya 7 working.
I create an ocean, add turbulence, change the wave size... add some foam... and just try rendering. Nothing major done, no boats, or wakes or anything, not even an environment (though this also happens when I have both).
If I render with Software renderer... it all seems to behave as I would expect it to.
If I render with Mental Ray... the geometry seems very rigid, and doesn't appear to deform at all frame to frame, but rather the textures seem to slide across the surface.
Is there something I'm missing? Is there a way to cache / bake the ocean? I'm trying to do a sunset shot, and it would be really nice if I could get the reflective properties of Mental Ray into this shot, but right now it seems like Mental Ray just won't cooperate.
Quicktime - Motion JPEG A - http://www.allegromation.com/HELP/OceanGlitch.mov
Seems like someone else has had the same problem... but no workaround yet.
http://discussion.autodesk.com/thread.jspa?messageID=5354464