If you don't know how to use a program: blame the program, not yourself!
I like your sense of humor, Hans! [:))]
But I know the frustration of being too lazy to learn the functions of the free software...
Still, this shouldn't be an excuse for such behavior - it's just arrogant and disrespectful!
Maybe this How to draw precisely -mini tip could help.
PS Don't miss Note 2 [:)]
PS2 If you don't need walls you could delete after create room.
A computer program does what you tell it to do, not what you want it to do. Murphy's Law When all else fails, read the instructions. Murphy's Law If you don't like "AS IS", DIY. Dorin's law