@OS_4design, unfortunately -- and contrary to appearances in the SketchUp plugin -- you cannot spatially define luminaires in OpenStudio. Well, you can, but all that gets rolled up to the actual simulation models is a load schedule. We regret this confusing presentation.
The plan was to leverage Radiance for spatially honest lighting layout representations, and to answer your question Radiance would be required for this; EnergyPlus is completely unaware of spatial luminous distribution. The plan was to be able to support this in OpenStudio by placing luminaires, associating a photometric distribution (IES) file to each one, and doing an electric lighting simulation with Radiance. We just never got there.
The OS:Luminaire object is still useful in the sense that you can use them to define your lighting loads at that level, but they are "flattened out" to these simple space-level lighting loads. An ambitious user could use the API to write some sort of luminaire-to-Radiance exporter, just sayin'. ;)