You can add spaces to a drawing using objects in a referenced floor plan drawing (xref) as bounding objects. Using the Space tool, you can generate a space for a room bounded by AEC objects, such as walls and floors, or AutoCAD objects, such as lines and blocks. The Space tool is located on the Analysis palette in the HVAC tool palette group.
When adding spaces, be sure to specify the appropriate space styles. After you create the spaces for a floor plan, assign engineering data using property sets. You also specify surface types, such as exterior walls, using the Space/Zone Manager.