Closed (perfect) radiation problems have no dependence on Ambient Temperature so that property is removed from the Details view during closed problems. The ambient temperature will not make a difference to surface to surface radiation assuming that the surfaces are totally enclosed. However for an open system if a surface can ‘see’ the surrounding atmosphere then that atmosphere will radiate to it and vice versa. For open enclosure problems using the radiosity method an ambient temperature needs to be specified (as a space temperature or a space node internally) to account for energy balance between the radiating surfaces and the ambient. In this situation the ambient temperature will have an effect.