1. A computer-implemented method comprising: quantifying similarities between a first multi-frame animation and a second multi-frame animation by determining a difference between content of corresponding frame pairs from the first multi-frame animation and the second multi-frame animation, and by summing the frame pair differences; combining the first and second multi-frame animations based upon the quantified similarities to produce a combined animation; compressing the combined animation to produce a first model that represents the content of the first animation and the second animation, wherein the first model includes a finite number of shapes; grouping the first model with a plurality of other models that share a common subset of shapes, wherein the common subset of shapes provides approximate renderings and wherein a set of non-common shapes provides detailed renderings; and initially transmitting the common set of shapes when only approximate renderings of the first and second multi-frame animations are needed.