Timing for Animation, 40th Anniversary Edition, 3rd Edition

Force Transmitted Through Jointed Limbs

In character animation, force is very frequently transmitted by means of more or less flexible joints.

An animal or man can be thought of as a series of fairly loosely connected sections. A leg consists of the thighbone connected to a ball and socket joint at the hip; the lower leg, with a hinge joint at the knee; and the foot which is fairly flexibly jointed at the ankle. The arm is jointed from the shoulder in a similar way. So if a subject’s shoulders are jerked backward, his hands tend to follow only after his arms are pulled into line with the centers of gravity of his hands (Fig. 21A).

FIG 21How ...