After several attempts, it appears that FormZ Free is the closest to SketchUp Make in terms of organisation!

An interface a little less "fluid" but we manage much better than Shape's interface, which is a little bit of a puzzle! :-P

And there are some nice little ones, staircases, automatic roofs etc... as well as a practical volume "unfurler"!
A hint of Nurbs...

A "all-in-one" performance for not a dime! ;)

Allows import SKP, dwg, etc... and export STL and DAE (so re-loadable directly in SketchUp).

If you have better do not hesitate!