Hey,
So I recently went to a lake, and when I was there, I saw some sort of god-ray caustics action in the water. The volume in the water, combined with the IOR and refraction of the water made god-rays. They were very close to the surface (1.5 meters max), and had a width of about 2-5 cm (if these measurements can even be determined). I would love to recreate the rays in blender.
So the thing was that they only existed when:
There was a volume for the light to illuminate
The angle of the water was the right angle for refracting the light
For the angle of the water, I was thinking that only certain angles allow light to pass through, as demonstrated in this picture.
The grey areas are the god-ray “zones”, the black is the water, and the red is the light.
This is only my rudimentarty understanding of light and bendy things.
I was wondering how to accomplish that. Also, if you have any tips on the volume, they would be greatly appreciated.
That would have been an effect of cloudiness caused by suspended particles in the water, which in theory should be quite recreatable in Cycles now that we have volume scatter. Just make a wavy surface using your favorite wave generator and remember to hook a volume scatter to your output node. I can make a test but because of the rendering times it’s quicker to tell you in writing and let you make your own test.
Aright, so I did as you said. I made a plane with the ocean modifier and placed a cube under it. The cube had a volume scatter with a density of 0.8. The ocean plane was a glass material with a greenish color and an IOR of 1.333. The world had a sky texture for color with nothing in the sky texture edited, and the strength was set to 1. I had a sun lamp at an angle shining down on the ocean as well. [Edit: The sun lamp’s strength was 133.0. Also, I had an emissive plane at the same angle as the sun lamp, and it’s strength was 300. Both light sources are white.] Here’s what I got:
RickyBlender: I would be very interested to see how you would intend to fake it. Also, not much to see for the nodes setup, just a single lonesome node plugged into the output. All the settings are in my above post.
in normal blender one way to fake it is to use a plane with holes in it and you add lamps inside to shine light in the water
but you don’t render the plane only the water!
let me try to find a sample file for this on my HD and be back later on !
Ah, okay. That seems like it would work if the camera were underwater, but in my scene, the camera will be over water looking down. Thanks for that anyway. It might work next time I want god-rays from underwater.
