Wall area pr. Room

I’m about to start a script which caluclates Wall areas pr. Room (meaning Doors, Windows, casework etc has to be subtracted in some Way. Im quite new to Dynamo and was hoping to get some advices. My approach Will be to multiply the perimeter with the unbounded height and subtract components. But how Would you deal with sloped ceiling?
AS meantioned i was hoping to get an advice or two:-)

Old thread, sorry…
But i am starting a script which should do exactly the same.
Did you succeed amyll ?
I have the same approach as you, but have much to learn :call_me_hand:
Thanks
//Spock