I'm sorry, but I can't find edit option, so i write a reply. I noticed, that in this file that i have it is even impossible to make a new room outside this house with a sloping roof! And if I open a new, blank file and do exactly the same, everything works just fine and I can get a sloping roof. So ...

Hello, i am a new user of SH3D, which I find very useful. However, i have a problem, which i really cannot solve, even though i tried many different approaches. I have a situation like this: http://i60.tinypic.com/9s467k.jpg

The higher part is 270cm high, the lower is 210 with a little slope at ...