1. A method for generating a sequence of video frames representative of three-dimensional animation, comprising the steps of: storing a plurality of key frames, each including a common figure having one or more joints, each joint having associated therewith a set of vectors defining a limb, each joint being defined in each key frame by operator-controllable parameters which determine in three dimensions the position, rotational orientation, and scale factors of a local coordinate system in which the limb vectors are placed; generating a plurality of in-between frames which include said common figure having one or more joints and associated limbs corresponding to the joints and associated limbs of said common figure in successive key frames, the parameters of the joints of an in-between frame being obtained as follows: (a) performing an interpolation, in each dimension, of the position, rotational orientation, and scale factor, for the local coordinate system associated with a joint, such that the interpolated parameter values of the joint lie between the parameter values associated with the corresponding joints of the successive key frames; and (b) repeating step (a) for other joints of said common figure.