Thank you Zoomer and Kevin for your comments,
Yes, I mean walls that start at a certain thicknes and finish at a different one (sorry for my weak english).
Here in Italy we work a lot on old building renovations, I would like to work on them in 3D/BIM as I would do with a new construction. So I would like to make a 3D model with a certain level of accuracy, let's say up to a 1:50 scale (I would probably draw more detailed features as old school 1:20/1:1 2D drawings, but potentially I could do them in 3d too). The best would be to be able to manage components as happens with standard walls. Actually Vectorworks is able to manage variations in the thicknes of them yet, it does in slabs with drainage tool.
To clarify what I mean I attahch an example, below you see the survey dwg and on it, in solid gray, the walls drawn in Vectorworks.
In other cases I have been modeling those walls just extruding but this is a larger project and I would avoid this solution since I need then to extract quantities.
How could I solve in your opinion? you made me come up with the idea of making wall recess shaped as the part of wall that I need cut, what do you think?
I don't know bricscad, maybe archicad does something similar? Anyway, now switching software is a difficult option.