Windowsill not perpendicular to the window?

[Anonymous]

I figured the easiest way to explain my problem would be through a picture, so here goes.

What I want is to make the red lines in this picture to be like the blue lines. That is, perpendicular to the straight inner wall, not to the angle of the windows. Is this possible?

[Erika Epstein]

You could place an empty opening or a niche on top of the window opening to create the horizontal cuts, but a little more information from you would be good first.

Is this a custom window?
What does the wall look like, it's sectional profile, without a window?

[Anonymous]

Hi Erika, thanks for the answer!

It is not a custom window no, I'm just new to Archicad and using it for a school project. The wall is actually two walls, on top of each other.

    _
  /  |         Upper wall
/    | ______    
\    |
 \   |         Lower wall
  \ _|

Like that. I suppose that's not the easiest way to do this, but you know, trial and error.

[Laszlo Nagy]

You could create the Slab that would define the intended shape of the cut in the Wall and you you use Solid Element Operations to subtract the body of that Slab from the Walls.