GBXML can get wierd some times; just due to the nature and many versions of gbxml that exist etc,
Do you happen to be able to share the GBXML?
be happy to take a look and see if can help
Hi Trevor, thanks for the offer but I think I’ve figured it out. If I split up the perimeter zones from the core zones I can add adiabatic surfaces/ air boundary’s. I wonder if it was thinking the external windows where actually internal?