Some of my clients needed to add/composite in some objects in to photo of empty hall so that they look close to reality. So it means that I should fake similar lights of original space, by making rough model – replica of hall so that light would come in and bounce in similar way. Camera matching and model was done in sketchup, then lighting, render layers – in blender. Thanks to volumetric rendering option of Cycles which allows to make clouds/steam.
