The actual rendered characters are quite low polygon count, but the modelers build very high detail (250k+ polys) versions that are processed by utilities to generate some of the data.

While we're stalking Carmack, he also made a post on /. talking about misc other things. This should amuse you college graduate types:

None of us had degrees in computer science. Romero, Adrian, and I don't have any degrees at all, and Kevin's is in political science.

Oh yeah, and no DOOM video releases are planned from the showing at QuakeCon. Doh?