10. A CAD system comprising a processor and accessible memory, the CAD system particularly configured to perform the steps of: loading an object model; receiving a selection of a first face of the object model; finding candidate wall faces and storing the candidate wall faces in a candidate list; designating at least one candidate wall face in the candidate list as a counterpart face to the first face based on at least one of geometric conditions, spatial proximity, or topological proximity; and storing the first face and the counterpart faces as a wall of the object model.
15. The CAD system of claim 10 , the CAD system further configured to perform the step of removing at least one second face from the candidate list based on an exclusion rule.