> Quote - > Ok, we'll let Harry decide.

I'm all for that. Sorry for disappearing. Sometimes sh*t happens.I'm following along closely and both room and ceiling are doing great. The rain stays out but the breeze blowing in the gaping hole in the wall does indeed leave a bit to be desired. On a scouting mission over to see about double hung windows now.
BTW I like the one sided sq approach for the ceiling. I can see through it at preview when setting a scene but it's always there for reflecting light when rendering.
Room rendered without ceiling of course.
pdg