The Facing Ratio shader can also be used to achieve this shading effect.
A rim shader is useful for achieving a lighting effect related to the contour/outline edges of an object. This tutorial demonstrates a simple shader that simulates a fake rim light shading effect. It can be useful for creating fresnel or cartoon like skin effects.
|This shader is available here.|
Rim shader network
Thanks to sample and hold for the use of the toy scan model.