Underwater Caustics

Wanted to play with volumetric lighting in Cycles to get an underwater scene. Just goofing around, and still lots of little things I could do, but decided to move on …

Textures are from CG Textures.



I’m impressed with how this came out… nice job. I’m curious on what approach you took on doing it… not the modeling so much as the caustics.

Thanks! Yeah … I didn’t spend any time on modeling. I just wanted to focus on caustics.

Basically, I fiddled with the volumetric settings in the world tab, combined with really strong spot lights filtered through an alpha map of ocean caustics. It took me about four or five hours of tweaking settings to get it right.

I’ve got another scene rendering at the moment. When it’s done, I’ll post some screen shots. That’ll be more helpful than my attempted explanations.

Thanks for the reply.

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Sorry … I got side tracked … maybe these will be more helpful …

Spot Light set up …

Environment set up with volumetric lighting


Hey! This looks really cool. I have one question, does anyone know how to make a scene with both above and below water visible? I can do the above water part easy, no prob, but mixing it with the underwater is extremely difficult. Any input?

I remember a scene a while back about the Loch Ness Monster … I think it was an entry in a Blender Guru competition … sorry, I don’t remember that much about the details. Anyway, it featured both elements really well. That guy may be a good starting point. You’ve got me interested in maybe trying it out …

Thanks for taking the time to post your breakdown. I need to play around with that falloff node and figure out how it works. I’m using a lot of spotlights in a indoor archviz project (see relapse in my sig) and perhaps I should try and integrate it.

That looks very cool!
Im trying to do the same, but my scene is very milky and i dont know how to fix it
And I do see the caustics very well, but not the rays

Hello All that’s great, i want to do the same on EEVEE, I have the volumetric lights, but for the caustics, is not easy, no nodes on lights.
If some one know how i switch the shadow in white.


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I am just starting to work with eevee but i think you would just have to invert the black and white to get the correct fx for the caustics.