A thin film is a refractive material that is assumed to have a thickness of 0, so light that refracts into the material immediately refracts or reflects out. This node accounts for all possible reflection and refraction paths through the thin object and returns the total reflection and refraction amounts.
The amount of reflected light will be returned in
kr, and the amount of transmitted light will be returned in
kt. The reflection and transmission vectors can be returned in the
T variables. Both
T will be normalized.
The global variables
N will be used if the incident vector and surface normal inputs are not connected. If connected, the
I vectors must be normalized.