Cell-decomposition:

In cell-decomposition, an object may be represented as the addition of cells into which it may be decomposed. Each cell-decomposition system described a set of primitive cells that are typically parameterized and are frequently curved. Cell-decomposition differs from primitive instancing in that we may compose more complicated objects from simple, primitive ones as a bottom-up fashion by "gluing" them together. The glue operation may be thought of as a limited form union in which the objects should not intersect. Further limitation on gluing cells frequently require that two cells share a single point, edge, or face. Although cell-decomposition representation of an object is unambiguous.

Cell-decompositions are also hard to validate, as each pair of cells should potentially be tested for intersection. Cell-decomposition is significant for use in finite element analysis.