2 floors open to one another

I have an atrium condition where the second level is open to the air space of the first level. Do I model these as one room, in which case how do I model the floor of the 2nd level?

Or do I model this as 2 rooms, in which case how to I differentiate between the air space connecting the two levels and the floor space of the slab.

The purpose of the model is to get an accurate daylight study of the space.

Hi @kinoeye - You have to set the face to an AirBoundary. That way it will be translated to a fully transparent face in Radiance and let the light go through. The easiest way to do that is to use the PO_SolveAdjacency command and set the SetAirBoundary option to Yes.

You can download a sample model from this study.