As far as I can tell, the specular material uses float IOR value. I want to create a material that's IOR is changing according to a mask distribution. (black is 1.0 white is 1.2 lets say)
I tried to connect a texture, I tried a mix material where the texture is mixing two fix values (values above 1). But I think it is just not working.
I also tried to create an OSl texture node, with output type float, but it is not allowed.