Easily computable object representations

Techniques are disclosed for providing easily computable representations of dynamic objects so that a graphic systems' physics engine can more accurately and realistically determine the result of physical actions on, or with, such dynamic objects. More particularly, disclosed techniques generate a convex decomposition of an arbitrarily complex polygonal shape that is then simplified in a manner that preserves physically significant details, resulting in an object having a relatively small number of convex shapes that cover the original polygonal shape. The salience of a physically significant detail may be controlled via a threshold value which may be user or system specified.