What exactly does it mean when it states that the reflection depends on the azimuthal angle? What would be an example of this in real life?

Hsifnus

I believe that reflection varying on azimuthal angle means that if the BRDF returns a particular value for one incident and exitant vector, the BRDF returned for the same vector pair but with a constant azimuthal (along the xy plane) angle offset is not necessarily the same.

What exactly does it mean when it states that the reflection depends on the azimuthal angle? What would be an example of this in real life?

I believe that reflection varying on azimuthal angle means that if the BRDF returns a particular value for one incident and exitant vector, the BRDF returned for the same vector pair but with a constant azimuthal (along the xy plane) angle offset is not necessarily the same.