Quake models used mesh animations, and this took forever to do this kind of thing to hammer out a model. With Skeletal animation, you only need to create the mesh, once. The skeleton is then animated and the mesh is later deformed to fit the skeletons animation on the fly. This is done by code that checks for the particular position of all the bones and making sure that the mesh that is assigned to the proper bones are in place for that particular frame of animation. Some deforming has to be done, this is why some animations may not be perfect, and reassignments of joints, or bones are done so the deformation looks realistic.
Lets get to work on our Skeleton.
I am going to be looking at a similar biped that would be used for the creation of the character that we will be eventually be making. This is going to be a secret for now as to how the player model is going to look. I would like to pause here a bit to show you how you can save yourself some time in the creation process of a biped. This means that you can decompile models that have a similar mesh build and taking the biped out of it. So start up Qped and lets extract it.