Im trying to replicate some specific RAL finishes and im not sure of the physically correct way of working with CIELAB values and gloss levels. Never had a client supply the data in this format before so im not sure if the conversion to rgb would be accurate given the smaller gamut of RGB within CIELAB.
Do i simply convert the lab to RGB?
Does real world gloss translate directly into a glossiness value in corona?
e.g. gloss level 13 would that be 0.13 in corona?
This feels like something dubcat would have experimented with but he hasnt been around for a little while.
I’m having a hard time sleeping and thought, why not do a random dubcat google search, and here I am.
RAL 7038 is pretty easy to convert to Albedo. RAL 5008 will get clamped because the LRV is 4%. I don’t know if Autodesk is the culprit, but both Corona and Vray will clamp these values to 0 RGB.
I forgot to answer the gloss question. Real world materials usually don’t go bellow 0.4 PBR glossiness. 13 gloss level does not equal to 0.13 pbr glossiness.
This is fstorms glossiness level mapped to PBR glossiness.
Current PBR glossiness does not exceed the material IOR. So if you do a cross polarized material scan of asphalt, and normalize the scan based on the F0 of the asphalt. And generate a glossiness/roughness map base on the asphalt F0. The gem stones in the asphalt will not have the correct IOR. Because the gemstones can not exceed 1.5 IOR. We need a new shader that read both glossiness/roughness and IOR/Specular at the same time. Modern render engines can not fake this stuff with geometry. Corona is stil using complicated IOR instead of real world easy math Specular.
