<t>I'm ass, I' did that many times, but in bad way. Thanks hansmex.<br/>
Now, I have room and I want to set dimension:<br/>
1) How to set dimension (length), for two collinear walls, for ex. from 9m to 7.50m? If I select one wall I have option to set length (via modify), but if I select two walls ...

I would terminate (close?) the room. I created room (4 walls, oblong) then I want modify size with mouse, three wall hold together, but last not. How join it?