1. A system for the characterization of plural dimensional objects, including representing images of such objects, from the intersections of curves with primitive solids and from set operations on said intersections from which said objects can be constructed which comprises a plurality of primitive classification means for computing the intersections of a plurality of curves with said primitive solids, a plurality of means for computing classification combinations arranged with said primitive classification means in a binary tree which defines the object by constructive solid geometry, said classification combination computing means each corresponding to a different node of said tree and having means for computing a set operation for its corresponding node.