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.