Hi,
When I looked at the physical approach of Nvidia’s paper, I was very confused about one part of the equation:

sqr( I - n²(1-(N.I)²) )

N and I are vectors.

How can you take the square root of a vector,
and how can you subtract a scalar from a vector?
AFAIK it is not possible.
Should there be a 1 instead of the first I ?