What are causatics and does blender have them?
Better look for caustics I think. They’re the fancy way light acts when going throu (sorry can’t spell this word right) different media like air and glass, or air and water. You then get fancy light effects.
http://en.wikipedia.org/wiki/Caustic_(optics)
Last time I read something about them and Blender was when Blender Internal got fake caustics enabled.