I had a go at recreating the relevant part of the Blender shader in Poser 13 and plugged the result into an emission node for visualization. The emission strength is 0 where we look head on at the surface and goes up to 1 where we look along the edge. This is before the falloff parameter is applied, so the value would be exactly 0.5 where we look from a 45-degree angle.

(The objects depicted are a sphere, a torus and a cylinder, in case that wasn't obvious.)

-- I'm not mad at you, just Westphalian.