How do you make a nebula?

Godsends and Drawbackssubhead : Has CGI replaced more traditional special effects? body : Well, CGI is both a godsend and it has its drawbacks - one of the things that is taken away is the kind of wonderful, fun, alchemy of figuring out how to use materials that were never intended to be used that way, to have the illusion of being something else. Where in the CG world, especially for ships, it�s a godsend because it saves us from sixty hours a week of shooting miniatures.

Certain things the computer still doesn�t do very well... explosions still don�t look very good. A lot of times we�ll mix generic explosions with computer generated debris.