Fresnel

3D Mask - Similar to Normal Vertices are selected depending on their normal orientation Read More , but specialized to select vertices that are oriented perpendicularly to the view direction

This modifier is usually used to create nice rim lights on the edges of objects but there is a lot more applications to this Mask in Smode.
here is a small tutorial to do nice mind-fuck effect with this modifier :

Parameters

  • Ratio of the fresnel
  • Exponent of the fresnel