WALLNICHE with hotspots editing it's section

[Anonymous]

I have made a window hole with editable section, which can be controlled on a floor plan.
The problem with the wallniche in this case is that I had to use pyramidal cut shape to make it work for every window edge, and with this mode the cut can only be SQUARE (with side length = A).
The goal is not only to make it rectangular, but also with one arched side.

Any ideas which way should I go to achive it?
Maybe some of you have already tried to do an object like this?

[alemanda]

I think you can cut and then add other volumes in order to get the rrquested shape.

[Anonymous]

Yes I know, I forgot to mention that I will do it the way you said if I won't find a better solution here.
And a better solution means using only cuts, because adding extra volume cannot contain wall layers - or am I mistaken?

[alemanda]

I think that you can add volumes and consider them as wall layers

[Anonymous]

Great!
Can you please explain it to me how can I do it? Or show it to me?

edit: I mean the real volume visible in 3d view and in a section, not the floor plan symbol.