This chapter provides some background information about the development of Cal3D. It does not contain any crucial facts you have to know in order to use the library, but it can help you understand why it was designed the way it is.
The origin of the Cal3D library lies in the WorldForge project: A nifty 3D client was to be built for it (see www.worldforge.org for more information about this system for massively multiplayer online roleplaying games). One of the needed components was a character animation system. Looking at the existing solutions available under a free license, it was obvious that most of them were based on one of the many popular first-person shooter games, and therefore quite limited in terms of flexibility and functionality. The decision was made that none of them actually fits the desired requirements. Thus Cal3D was born, most probably the first library specialized on character animation released under a free license.