Mapping IOR?

[LarsSonparsson]

How to use map in IOR slot?
If I'm using bw map, is the value 128 IOR 1? And what is value 0 or 255 then?

I didn't find anything about this in manual or forum.

Thanks,

LarsSon

[vlado]

The IOR map is a multiplier for the IOR value specified in the interface. So if your map is white, the IOR will be as specified in the reflection/refraction options; if the map is medium grey, the IOR will be half of that value and so on.

Best regard,
Vlado

[gagui]

I want to make sure this is still working that way because I'm finding very difficult to map IOR parameter.
It seems like is working with floating values now, isn't it?

What is the best way to map a gradient for the refraction IOR?

[Art48]

I would be interested as well - especially what would be a use case? Or is this parameter purely mappable since it was kinda "easy to implement" or sth? Or has it an actualy physically-correct way of being used?

[Svetlozar Draganov]

The IOR map is not actually a multiplier of the IOR value, by default it replaces the specified IOR value with the value from the texture.
Of course you could mix both values by changing the blending percentage, in that case you will get averaged IOR value, for example if IOR value is 1 and IOR map value is 2 and the blending is 50% the resulting IOR will be 1*0.5 + 2*0.5=1.5

IOR=1.5

IOR=1, IORmap=2 (50% blending), final IOR=1.5

[samuel_bubat]

I would be interested as well - especially what would be a use case? Or is this parameter purely mappable since it was kinda "easy to implement" or sth? Or has it an actualy physically-correct way of being used?

You can make some nice physically correct predator like shader

[Art48]

I don't get what you have done there, sam. 100% refractive material with fog? And what effect exactly does the mapped IOR have? "Just" variating the IOR with some kind of noise map so an actual geometry form can't be really determined?

[samuel_bubat]

I don't get what you have done there, sam. 100% refractive material with fog?

This is just an example of how a mapped IOR can be used. Attached is a screenshot. In the IOR Slot I use 2 output nodes mixed by a falloff. The RGB Level of each output node represents the IOR. In this case 1.1 for the first and 1.0 for the second. The falloff curve is shown on the right. The fog is just to make it more visible. It looks pretty nice when the geometry is animated. Probabely not someting one can use in a usual project but anyway, nice to have.