Per-wall footprint rectangles (4 CCW corners, room frame) for the walls whose
height range overlaps the storey band [floorElevation, floorElevation + floorToFloor]. Aggregates all mesh fragments of one wall (a void-cut wall
renders as several) by expressId before taking the OBB.
Per-wall footprint rectangles (4 CCW corners, room frame) for the walls whose height range overlaps the storey band
[floorElevation, floorElevation + floorToFloor]. Aggregates all mesh fragments of one wall (a void-cut wall renders as several) byexpressIdbefore taking the OBB.