A (DOP) generalizes the bounding box. A k-DOP is the Boolean intersection of extents along "k" directions. Thus, a "k"-DOP is the Boolean intersection of "k" bounding slabs and is a convex polytope containing the object (in 2-D a polygon; in 3-D a polyhedron). A 2-D rectangle is a special case of a 2-DOP, and a 3-D box is a special case of a 3-DOP. In general, the axes of a DOP do not have to be orthogonal, and there can be more axes than dimensions of space. For example, a 3-D box that is beveled on all edges and corners can be constructed as a 13-DOP. The actual number of faces can be less than 2 times "k" if some faces become degenerate, shrunk to an edge or a vertex.