[Baden3DMAX13]

Ok, I've got some input & some questions... first off are you useing max six, if so you can utilize mental ray to do most of your underwater caustics effects... only thing is this takes a lot of processing power... Ok, for the underwater "look" use the fog effect thing, it works wonders, next for the caustics you can use one of two things, a light above the entire scene that projects a picture of caustics down onto the scene, or thru mental ray. To do it thru mental ray, make a plane above your scene and add a noise and a wave modifier to it to give it that wavey watery look, next go to your renderer by pressing f10 and go down to the bottom to assign renderer, click on default scanline and change it to mental ray. now go into your material editor (m) and change the material to a watery looking material, i'll give a specific one later... assign that material to the plain, now you're ready for the fun part... to add caustics to your scene, select the plain and right click on it to go into it's properties, go to mental ray properties and make sure that generate caustics is selected. Now click ok and go back into your render rollout, go to renderer properties(i think that's what it's called...) and go down to caustics, turn them on... you're almost done, i'll post the rest on here once i look at it and get some values for what you're doing, but without it in front of me that's what i've got off the top of my head :-)