Caustics

[Tobias Jansson]

Hi!

I have a slight problem, I am rendering a scene with a pool, and I use caustics. I get nice refractive caustics on the bottom of the pool but almost no reflective caustics on the sides above water. Is there a way to brighten only the reflective caustics and not the refractive?
thanks!
/Tobias

[Aldaryn]

Just render out a hdr caustics pass where your water has no refraction, and there you go, you'll have full control over reflected caustic light from your pool. Also, keep in mind, that water has an ior of 1.3, so in reality pronounced reflected caustics will only be visible if the source light has a pretty low incident angle. So, you might just want to tweak the light setup in your scene.

best regards,

A.

[DaForce]

you could increase the reflection IOR of you water until you get what you want for refraction and reflection caustics, save that caustics solution and set your water back to normal.

[Tobias Jansson]

Thanks!

will a saved caustics map work for animated caustics? in other words, does it add to the current map? I guess I could simply try it but I am a bit pressed on time here..

Thanks again!

[DaForce]

Ahh no, that wont work for an animated caustics map as the caustics map will need to be calculate each frame.

You could script it. so that you could calc a new caustics for each frame (without rendering the final image) then reset the water settings and then load the specific caustics map per frame when doing the final render.

You could try increasing the causitcs MP, but that will then start blowing out the underwater ones.
What you may be asking for may not be a realistic result and thus abit tricky to achieve.

[Tobias Jansson]

Yes what I am looking for is something that looks nice but not nesecerally accurate.. I guess I could do a simple fake with projector lights that projects caustic like patterns where I want them, simple and fast to render.
Thanks
/Tobias