For many games, the model include pre-determined bone rotations that form an animated sequence. You could, for example, play 10 frames that might be a walking sequence, or another 25 frames of a death animation, etc. It is usually the job of the modeller/animator to create these animation sequences, add them to the model, and document them. The programmer can then just call the desired set of frames as needed.
That's just the tip of the iceberg when it comes to 3D animation. DBC and DBP are about programming. Search through the back issues of the newsletter and around August of 2003 you can find demo files and media files for the alienware contest. Download those and check out the source code and you'll see exactly how animation can be performed.
I hope that helps to answer some of your questions.
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TAZ
History did not begin with PONG. -- Greg Costikyan
Game Beavers