A room is a model element, so you can add rooms to a design option. As a general rule, the perimeter, area, and volume of the room are defined by the room-bounding elements available to that option. These room-bounding elements include elements in the main model, elements in primary options of other option sets, and elements in the secondary option itself. However, a room in a secondary option cannot reference elements that are defined in other secondary options.
Room-bounding elements can include walls, room separation lines, roofs, floors, ceilings, columns, and curtain systems whose Room Bounding property is turned on. (See Rooms and Room-Bounding Elements.)
For information about errors regarding rooms in design options, see Option Conflict Between Rooms and Room Option Conflict.