OpenStudio 2.1.0: Radiance and Daylighting

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The Radiance measure will use Radiance to calculate the daylight availability in spaces that have daylighting controls and illuminance maps in them, and will, in turn, reset the electric lighting schedules in those spaces' thermal zones. This lighting schedule is then used in the EnergyPlus simulation and the effects on the building's energy use will be reflected.

You may add shading controls to the windows as well (only a subset of the EnergyPlus options are available, and they are all inside the window to answer your question), and they too will operate on an hourly basis in response to the solar load on the window group the shading control is applied to.

Documentation: OS-Radiance functionality, shading controls, 3-phase method

That's the how of the Radiance measure. In terms of the why or the where, the best practices, that's essentially beyond the scope of this forum.