Make it clear that the fuzz-layer inherits its IOR from the surrounding medium. If this was not true, then there would be a Fresnel reflection from the fuzz.
I don't think there was a discussion about this, it just came up when I was looking at the implementation of the Disney model. There is no Fresnel term, it is just like a volume (of anisotropic microflake particles) sitting in the ambient medium. So I just wanted to be explicit about that in the physical model. If it was not index-matched, then what is the IOR of the fuzz? (Since we don't specify, it must be matched). Also this impacts the coat model -- since its Fresnel depends on the fuzz IOR. Which we have to assume is the ambient IOR.
virtualzavie
commented
11 months ago
Make it clear that the fuzz-layer inherits its IOR from the surrounding medium. If this was not true, then there would be a Fresnel reflection from the fuzz.
I don't think there was a discussion about this, it just came up when I was looking at the implementation of the Disney model. There is no Fresnel term, it is just like a volume (of anisotropic microflake particles) sitting in the ambient medium. So I just wanted to be explicit about that in the physical model. If it was not index-matched, then what is the IOR of the fuzz? (Since we don't specify, it must be matched). Also this impacts the coat model -- since its Fresnel depends on the fuzz IOR. Which we have to assume is the ambient IOR.