Hey, I'm keen to enter this one in the MDL contest but I would have thought the whole material would need to be done in MDL using many layers for the different colours facing the view angle with different IOR. That's how I'm trying to approach it anyway, just using a normal map from a substance graph for the geometry. How did you get so far with just a regular PBR shader? You have the orange specular quite accurate and even the "gray rings". How much of that is baked in to the colour map vs utilising metallic texture, etc?
I do not think that it is necessary to create many coated materials with different IOR, one translucent material with the Fresnel reflection at sharp angles should be enough. The key to the reflections is the panorama map, which can be created directly in the SD. In addition to the normal map, I also use the height map, which, while distorting the geometry, in PBR mode does not create a light scattering. Therefore, for MDL, you need to create a white matte material coated with another translucent material that reflects light only at sharp angles (f.e. from the translucent template).
I use the Color/Metallic/Roughness workflow, so the color of the reflections is obtained from the panoramic map (except for gold material), the rest comes from the color. In MDL, the color of reflections can also be obtained by the color tint of the coated material.
