Long, long ago I saw an article or talk by Paul Haeberli, of SGI. Oh, he covered many interesting and clever graphics tricks. One of them was the idea of “synthetic lighting”, or, “doing lighting in post”.
He has a page about it, here.
The idea is pretty simple. If you have images (or animations) of individual lights, you can add them together to get multiple lights. It appears to be a relatively common render feature these days, but I’d never played with it before. So here goes.
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You can color and mask them, too, to get some pretty nifty effects, all from the same source images.
The pictures above, showing my infantile modeling skills, were done in Luxology modo, using full radiosity render. This can take a while! 10 minutes per low res frame, about.
The youtube video below shows some further examples of getting liveliness out of just a few frames, using this idea of additive post-process lighting.