behaviour of multiple source objects in one scene

Hi folks,

after how many gensky-calls I start to wonder - what does it mean to have to source objects (sky & sun) in one scene?

Having one source is easy to get - it takes the bounding box of the scene and catches all rays that leave it. Having two....? Is it that the order the source objects are defined determine their "diameter"? The typical example is the sky and sun combination, both of type source. Usually I have the gensky-output first including the sun disk, and the hemispheres for sky and ground after that (and added by hand). Does this mean that, because of their order in the scene description, the sun source is "inside" the sky source? And does it make a difference whether the source objects are modified by light or by glow? So if I could handle the sun as glow, would it still "override" the sky background because of the order of its definition?

Sorry for not finding this out myself now in the source code, maybe someone can shed some light on this?

Cheers, Lars.