Shading:Building:Detailed shading more area than it should

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Hello everyone,

I am trying to model a dynamic shading device intended to block solar radiation over OPAQUE SURFACES. In this case, the product is intended to shade the roof of a building, but not its skylights. The device can be deployed (when there is a lot of solar radiation) or closed (when solar radiation is benefitial).

I modeled the building in EnergyPlus as 4 rectangular Shading:Building:Detailed (to avoid holes), with a transmittance schedule defined as a Schedule:File. The Radiation Calculation is done on each timestep.

The geometry of the device is such that it should not shade the skylights, even when it is deployed. However, the solar gains through the skylight are proportional to the solar heat gain over the roof.

So, my question is: Is, the incident solar radiation on windows (thus, the solar heat gains), calculated as the average of the solar radiation over its containing surface? Can EnergyPlus consider that the window may be fully exposed to solar radiation even when its containing surface is not?

For now I will split the roof on several surfaces, some of each containing skylights and some of them not.

Thanks!