. You can control the presence of facing walls in the room with Room OptionsAdds a polygonal room with a floor and wall to the drawing. The appearance of the surfaces is determined by the current Perspectives Settings . You can control the presence of facing walls in the room with Room Options
To add a polygonal room:
1 On the Perspectives toolbar right click Rectangular Room 
then click Polygonal Room.
2 Either type a thickness and press ENTER or click two points the required distance apart, or right click to accept the default (previous) value.
3 Click the first point for the polygonal floor.
The prompt reads "Next node [done/close]:"
4 Click a second point.
The prompt reads "Next node [done/close]:"
5 Click further points, then right click to close the shape.
The prompt reads "Wall thickness[n]"
6 Either type a thickness and press ENTER or click two points the required distance apart, or right click to accept the default (previous) value.
The prompt reads "Height[n]:"
7 Either click a point on the top of the wall, or type a height then press ENTER or right click to accept the default (previous) value.