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LowEndFrequency
03-14-2003, 05:02 AM
How would I create the effect of a white light breaking into its spectrum, as if it were shinig through a crystal prism? A good example of this effect can be found here http://splutterfish.com/sf/gallery_view.php?photo_id=231&screen=0&cat_id=2&action=images . Ive been experimanting with caustic lighting, but I don't think it can achieve the effect I need.

Any suggestions or helpful hints would be much appreaciated.

jeremybirn
03-14-2003, 04:51 PM
The "chromatic aberration" checkbox is supposed to give you colors like that when you're using refraction. I don't think that gets cast into the Caustics though, so you'll have to build the effect yourself.

Render the scene at least 3 times, with white light and no chromatic aberrations, but with 3 different Refractive Index settings on the surface, making slightly different position gray caustics in each render. Comp the passes together with one going into the red channel, one into green, one into blue, and you'll have colors added to the gem and the caustics. If there are banding artifacts, use more than 3 passes and tint them into secondary colors as well.

-jeremy

Jozvex
03-14-2003, 09:30 PM
Hmm ok, how about the image I've attached? I managed to get that in Mental Ray.

I used caustics but the colours are not the proper accurate colours, I just used a photon shader and applied a ramp to it. That way you could choose what colours you want the caustics to split into!

LowEndFrequency
03-16-2003, 04:59 PM
Thank you both! This is exactly what I am talking about. I'll try both techniques and see which I get a better effect from.
Much appeciated.

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