Halo effects through materials

I was wondering if there was a way to get a spot halo to shine through a transparent material. Basically, I’m trying to make a underwater scene, caustics and all, but at the moment I was wondering if there was a way to simulate light rays shining into water that’s kinda dirty, or should I try to fake it with materials (a mask) on the lamp?

Also, if anyone could point me to an article on caustics, I’d greatly appreciate it, I’ve browsed around but haven’t found anything on simulating water caustics, yet.


I usually go the mask on the lamp route , it gives better results most of the other ways of doing it are nightmares to pull off…slow to render …and not very good results. There is a program somewhere to generate animated caustics (free) Ill find it real quick and post the link… it puts out bmps and or tga’s
so youll have to use the sequencer to assemble them into an avi texture which you can then add to your light (I have gotten pretty good result using spots with a halo factor )… ok the website turns out to be temporarily down so here is the link for when it is back up http://www.lysator.liu.se/~kand/caustics/.
I usually take the images the program makes and apply a lite guassian filter to each one an image processing program.

Ok, thanks. I downloaded it the other day, but haven’t looked at it yet.