I'm debating the best way to model a 4m thick roof structure consisting of upper layer metal sheet (inter-spaced with skylights), layer 2 is insulation, layer 3 is cavity void air 3m, inner layer is a PTFE coated fiberglass construction meant to act as a diffuser to create a illuminated ceiling (i.e. translucent).
I'm thinking that the floor construction base surface will be opaque...can one add a Window sub-surface to a floor (which will be the roof of the next level)?