manual
In this way you can draw the floor in one piece while leaving an interior area open.
5.5 Split-Level Buildings
To represent buildings with split levels, import a drawing for each partial level and draw in partial floors for the existing floor areas. Remember, though, that walls you draw in on a lower level extend only to the height of the next higher level, even if they do not meet a floor there. If your building has walls that extend through a split level, you must draw them on the lower level and again in the unfloored space on the next higher, partially floored level.
28
