could be a few things, sometimes I make sure there is more overlap of the operator than needed to make sure the target is covered when the operation is executed. also trying different execution methods like " with upward extrusion" might be worth a try.

@@archguide I tried all of them, including overlapping without any success. I managed to do it by making a morph and extruding in 3D instead of a complex profile. Then I use the substraction operation and it works.

@@dreamess6266 Ah beauty, thanks for sharing your solution!

Thanks for the heads up! will take a look at it now

A high set empty corner window would do the job, to show the cut in plan view. Just also make sure the wall setting "symbolic cut" is on so it shows the window symbol no matter how high you put the corner window.

THX!@@archguide

No worries!@@ayan13yxq

If you watch enough tutorials and you have the drive to learn, I can't see what could stop you mate.

@@archguide thanks man. I will do this. Just wondering what’s better, sketch up or archicad? Do you have any advice.

​@@boxoffisa If you need full documentation like floor plans, elevations, sections, site plan.. I'd go ArchiCAD. But if I was on a tight budget & just need to model up a basic 3D form I'd start with SketchUp.

@@archguide thank you mate. I found archicad to be easier to learn. But what it offers I would go with it. It’s what I purchased.