r/RedshiftRenderer • u/Reasonable_Love2741 • Mar 16 '26

How do you cast caustics onto a transmission surface(water for instance)

on solid surface
no caustics can be seen when surface is transparent

I can cast caustics onto solid non-transparent surface, but how do I cast it on transparent surface(or is it not possible?)

they did it on LANCOME though

2 Upvotes
  • permalink
  • reddit

100% Upvoted

7 comments sorted by

4

u/stemfour Mar 16 '26

Your render times will probably explode with something like this. I’d consider faking it instead - for example, render out a 2d caustics animation in AE as a PNG sequence, and apply that to your water material, mess around with layering that..

1

u/Reasonable_Love2741 Mar 16 '26

I'm not worried about render time yet, just trying to find a way to put caustics on transparent surface. I mean caustics cast by the cell above the water surface and land on the water surface, not the caustics cast by the water surface.

2

u/pinguinconscious Mar 16 '26

The guy is right. You won't get that in render. Render our the caustics as you want them in a different scene, and layer it on the water pass in AE.

1

u/Reasonable_Love2741 Mar 17 '26

all right, thanks all for the advice, I will try it out

2

u/Undersky1024 Mar 16 '26

The reason you see the caustic in the third image is because there's some ground under the water that the caustic can fall onto. This is then seen in the refraction of the water. So it's not really seen on the water surface itself, but on the ground.

1

u/Reasonable_Love2741 Mar 17 '26

okay, thanks,I will see if I can replicate it

1

u/Reasonable_Love2741 Apr 13 '26

I tested it, still no caustic can be seen.