Subfloor or platform

by BKLX » Fri Jun 05, 2020 12:15 pm

Hello,
I'm a novice on this forum and on this sftware. And to complicate... I'm French! [:))]
So I need help to create a ''subflore'' or a ''platform'' I'm not sure of the good word.
To complicate, this false floor has not the same perimeter than the real one.
If you can help me I will appreciate
Have a good day
Bruno