6. The method of claim 5 , wherein the old input graph, the new input graph, and the old output graph are face-edge graphs or edge-vertex sub-graphs of boundary-representation graphs.
7. The method of claim 6 , wherein the old input graph, the new input graph, and the old output graph are edge-vertex sub-graphs of boundary-representation graphs, and the method further comprises, prior to applying the rewriting rule: retrieving from the associated memory, an old face-edge input graph of the 3D model before undergoing the operation, the old face-edge input graph being a sub-graph of the boundary-representation graph of which the old input graph is a sub-graph, an old face-edge output graph of the 3D model corresponding to an application of the operation to the old face-edge input graph, the old face-edge output graph being a sub-graph of the boundary-representation graph of which the old output graph is a sub-graph, and a new face-edge input graph of the 3D model undergoing the operation, the new face-edge input graph being a sub-graph of the boundary-representation graph of which the new input graph is a sub-graph; computing a face-edge rewriting rule that specifies a part of the old face-edge input graph to be replaced, a part of the new face-edge input graph to replace the specified part of the old face-edge input graph, and a face-edge interface which is a part common to the specified part of the old face-edge input graph, the specified part of the new face-edge input graph, and the old face-edge output graph, the face-edge rewriting rule corresponding to logical operations which are computed based on the old face-edge input graph, the old face-edge output graph, and the new face-edge input graph; computing a second face-edge rewriting rule that specifies a second part of the old face-edge input graph to be replaced, a part of the old face-edge output graph to replace the second part of the old face-edge input graph, and a second face-edge interface which is a part common to the second part of the old face-edge input graph and the part of the old face-edge output graph, the second face-edge rewriting rule corresponding to logical operations which are computed based on the old face-edge input graph and the old face-edge output graph; and testing that the face-edge rewriting rule and the second face-edge rewriting rule are not commutative.