It maybe not the effect you're looking for, but it does demonstrate how the atmosphere effects the 'particle' look of the light source. The GI detail up to 3, shows me how the light bounces around the stones and surface detail more accurately. If you wanted the light source to be more prevalent, then increasing it's physical size would do that. If you wanted to lose the 'particle' look, then more cowbell needs to be applied to the atmos quality. Either way, an interesting exercise, thank you.
