OTOY Forums

Hey all?

How would you create decent looking underwater caustics? Is there a way to use Gobos or similar maps to affect light intensity; that would be my first guess to create the effect, but I can't seem to get it work.

Thanks,

hi,
I have moved your question to the 'Resources and Sharing' forum as you might get more tips from there... cheers

Currently sunlight does not cast caustics in this way.
You need to use an HDR and place a sphere or disc (low poly) at a large distance so simulate a sun with an area light, then render with PMC.
You just need to displace the water geometry for wind/motion first, then export to octane and render.

I am also trying to get any underwater caustics using emitter + hdri. No success . Can you show me at least some that had achieved the result with octane?

dude, you´re crazy. I highly suggest to use a different approach:

Render your scene in octane without caustics.

Now generate a caustic texture in the desired resolution. Still frame or as a loopable animation.
Use this tool to accomplish the task easily:
http://www.dualheights.se/caustics/
it´s also available in a "free" version.

Back in your 3D core app:
Apply this caustic texture to your geometry using projection mapping (from above).
Render the scene conventionally as separate pass/layer and screen/lighten/add this in post over the image you got from octane.

done.


edit:
oh, I see that the free version of the caustic generator supports only a resolution of 512x512.
So better use some texture-tiling or get in touch with the pro-version.

I did a quick 10-minute example: check out the attachment.