In the presentation there was a reference to a Parent/Child relationship. The parent for doors and Windows might be Walls but the relationship between Walls or multiple Windows or doors would be that of a "Sibling" or "Peer" component to maintain logical consistency of the objects. I would also recommend a Junction Object, which means more than an Edge because it would describe the two peer objects that were being joined, and the angle of that junction between the objects. The Junction could also describe the shape of the junction to capture any curvature or discontinuity of the junction. Multiple junctions might also be peers because they would have a junction between other adjoining surfaces giving a more complete description to the structure of the room. The parent of all of these surfaces and junctions would be the Room itself. Such a description would be useful in an architectural review of the room structure.
