Why does the mirror material not consider the fresnel reflection?

[1112]

According to the document “Behavior of Materials in Radiance,” it appears that the consideration of Fresnel reflection was omitted. This is evident from the constant reflectance, which does not vary with incident angle. I have also conducted tests and confirmed that the Fresnel effect was not taken into account. Therefore, I would like to inquire if there is a way to adjust the normal reflectance based on the incident angle when utilizing mirror material for calculating specular reflectance of facades.

[Stephen_Wasilewski]

Hi,

See this post:

Directional reflectance of glass

Hi Chris, Radiance doesn't find the illumination of the sun off the glass material because the sun is too small to locate with random (Monte Carlo) sampling. The "mirror" type is the one to use, and you can account for the effect of angle on reflection by including an appropriate brightfunc pattern. Assuming standard 88% transmittance glass, this would be: void glass glass_alt_mat 0 3 0.96 0.96 0.96 void brightfunc glass_angular_effect 2 A1+(1-A1)*(exp(-5.85*Rdot)-0.00287989916) . 0 1 …

[1112]

Thank you so much, Stephen!