I would place a section cut somewhere high enough to "reach" the windows, too. Then make a top view scene with this and in the Tray > SU model you can set which scene you want to display.

LOView.png
Also see the attached LayOut file and change between Page 1 and 2 to see how different scenes (with different views, camera settings and section cut visibility) of the same model can be inserted like this.

(Now if we had dimensioning in LO, it would be perfect!)
😉

HouseWithSectio.layout

Is the model aligned to the axes in SU? (I mean the original world axes) Also, have you set your camera to parallel projection in SU?