Thank you for the answer.

Yes, I checked the EnergyPlus references, and I am aware of using the index of refraction in some formulations in the EnergyPlus.

However, EnergyPlus only uses the index of refraction to obtain some other radiative properties such as transmittance or reflectance. It does not use the index of refraction to consider the incidence angles changes when the light passes through different mediums with different indexes of refraction. For instance, you cannot see that EnergyPlus has been used Snell's law:

I think, as you mentioned with the image, because the direction of light after it passes through the glass window is the same as the direction before it, EnergyPlus ignore the angle changes inside the glass layers. But, it definitely makes some errors (although small) in calculations, such as shadow calculating inside the building.

Therefore, again I emphasize my previous conclusion:

"EnergyPlus "EnergyPlus does not consider the refraction of light (incidence angles changes due to pass light through the mediums with different indexes of refraction) in calculations".

Thank you for the answer.

Yes, I checked the EnergyPlus references, and I am aware of using the index of refraction in some formulations in the EnergyPlus.

However, EnergyPlus only uses the index of refraction Update to obtain some other radiative properties such as transmittance or reflectance. It does not use the index of refraction to consider the incidence angles changes when the light passes through different mediums with different indexes of refraction. For instance, you cannot see that EnergyPlus has been used Snell's law:

my question:

I think, as you mentioned with checked the image, because EnergyPlus references and searched in Google to find out whether the direction EnergyPlus consider the refraction of light after it passes lights when they pass through the a glass window is the same as the direction before it, EnergyPlus ignore the angle changes inside the glass layers. But, it definitely makes some errors (although small) in calculations, such as shadow calculating inside the building.

Therefore, again window. In conclusion, I emphasize my previous conclusion:think that:

"EnergyPlus does not doesn't consider the refraction of light (incidence angles changes due to pass light through the mediums with different indexes of refraction) in calculations".