A so-called “non-convex” space or zone is one where one or more surfaces cannot “see” one or more of the other surfaces in the space or zone. A common example would be an “L” shaped zone. If EnergyPlus is run with “Solar Distribution” set to FullInteriorAndExterior, a zone like this will create errors. However, CBECC-Com runs the EnergyPlus models with Solar Distribution set to FullExterior. In this case, beam solar radiation entering the zone is assumed to fall on the floor, where it is absorbed according to the floor's solar absorptance. Any radiation reflected by the floor is added to the transmitted diffuse radiation, which is assumed to be uniformly distributed on all interior surfaces. Non-convex spaces or zones do not create problems when FullExterior solar distribution is used.