Someone explain this to me. I'm currently learning Substance designer and in the tutorial they say that the shader has a hardcoded 4% F0(Fresnel 0° angle) for dialectrics, since most of them basically have this or a very close value anyway, but Arnold and other offline renderers use float numbers instead of percent to calculate fresnel, is 1.52 IOR equal to 4%? And how can I see the grayscale value?
you should just use real life IOR valueshttp://forums.cgsociety.org/archive/index.php?t-513458.html
>>562335How can I do that in substance? How does Rubber 1.5191 IOR translate to % in Substance?
>>562336i don't think it has anything to do with the fresnel values. this is related to the shader and not the textures.substance have proprietary shader which you cannot change. however you can change the IOR value in a render engine like arnold.i mean, you should. i can do it in cycles then im sure you can do it in arnold
>>562342It does, the 4% reflectivity on F0 is hardcoded since most dielectric materials use values from 2% to 5%, 4% is a nice middle-ground value, you can change it in case you're working with materials that are the exception, or if you really want to be as physically accurate as possible, but it needs an extra step. What I'm trying to understand is, when importing Substance materials to Arnold or other renderers, how do I convert the percentage value to IOR units? Is 4% = to 1.4? and 9% = to 1.9? What about non-metallic materials that have huge values? I mean, there are like 2 or 3 in the universe but how would you go about doing that? Would you just make them metal since at that point there's no diference?
>>562345well i personally tweak my IOR in regular numerical values and not in like you just showed so i don't know what to tell you.>In case you ever need it. The conversion from IOR to F0 is:((1.0 - IOR) / (1.0 + IOR))^2just copied it from here, im not a math guy so i don't know what the hell that meansfeel free to dig inhttps://blender.stackexchange.com/questions/73009/how-to-make-a-node-group-to-calculate-fresnel-via-f0-valuespic related is how my shader looks like
>>562348and this is how my PBR shader looks like, but i didn't make it myself.i think this is the F0 convertion
>>562349Just use Disney shader and forget about this shit. Spend time on something more important.
>>562364Unrelated but this movie doesn't look too good on screenshots.
>>562364people are going crazy over PBR and rightfully so. its easy fast and looks good. but you don't need a clusterfuck of shaders in most cases, just good art
>>562371That's one of the advantages of PBR, you don't need a clusterfuck of shaders, just one standard/uber shader.