Get Specular reflections from IOR

The official Blender documentation provides a method to get the “Specular” value for the PBR-material reflections if the “IOR” value is known. To get the “Specular” value from the “IOR” value, we can use the following equation:

It is not difficult to create it with nodes:

To do this, add five “Math” nodes

shift + a – Converter – Math

and connect them as follows:

It should be noted that this equation is valid only for dielectric materials. For its proper work you must specify real IOR values, for example:

  • water IOR  = 1.33
  • glass IOR = 1.50
  • diamond IOR = 2.417

The node group “IOR to Specular reflection” can be downloaded from the BIS library:


Author: Nikita

Blender add-ons developer and articles writer.