FresnelFade material settings?

The only settings in this FlightSimulator material type I can find that
might have something to do with camera angel are Fresnel Factor and
Fresnel Opacity Bias What if any relationship do these have to the camera
angle and how the texture is revealed? An explanation or link to one would be
great. I actually have it working but I am flying blind with it. Just guessing
and not understanding. And the SDK docs are of no help, unless I am not
looking in the right spot which may be. Thank you.