In the building trades we built many ceilings call coffered ceilings.
In chief it is something different (terminology?).
I want to have a say 10-12 Ft High flat ceiling with all four sides slopping back to top plate (pitch adjustable).
Attached is a rough sketch.
Hopefully someone can enlighten me. I usually can figure out or find info on problems, but this one has me stumped.
TIA Gerald