I got a 3D model using a material, which has a color channel of an image-texture-map for IOR.
When I want to allow my renderer to apply such maps through a MDL material I encountered some problems.
for non-metal materials I have seen how to apply the IOR in the example “flex material” in the MDL SDK within the fresnel layer; but for “metal” materials a weighted layer instead of a fresnel_layer is applied.
see here: https://github.com/NVIDIA/MDL-SDK/blob/master/examples/mdl/nvidia/core_definitions.mdl#L1843
there is no IOR. Although I read that for example Gold has an IOR of about 0.470, so metals also could also have an IOR value, right?
When that value is uniform throughout the material, it can be added in
in the material( … ) part:
where “ior” is defined, but how to apply that value if its read from a texture map ?
The material I got has only a solid color, so I could instead use it for that case as uniform color without the texture map access.
I’m not sure, whether there are cases of different IOR per pixel, are there such ?