Specular Level to IOR (dielectric) by Jens Kafitz
Specular Level to IOR (dielectric) will convert dielectric Specular Level values to a corresponding IOR.
Specular Level Maps are popular in a game-PBR workflow and are found for example in Unreal Engine, can be output from Substance Products etc..
You can also utilize Specular Levels in the Mari UNREAL and Extension Pack UNREAL Advanced Shader (just called 'Specular')
They define the reflectance of dielectric (non-metal) materials from 0 % (0.00) to 8 % (0.08) via a remapped value of 0 to 1.
In most cases these Specular Levels are set to 0.5 which in Reflectance terms is a 0.04 surface reflectance equaling plastic.
Some sample measured Specular Level Values can be found below (taken from UNREAL Engine Documentation)
Material Specular Level
When the Manual Input option of the node is disabled you can feed in values from other layers or nodes
that will then be converted.
When ticked, the Node will no longer act as an adjustment layer, converting values fed in from other nodes
or layers. Instead it will output the converted value from the Specular Level Value entered via the Slider.
The Specular Level Value to convert when Manual Input is enabled
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