Computer graphics (until PBR) were rubbish.
Graphics were using values which bore no resemblance to actual materials, they were a semblance. A fake, a forgery. If you were ask an artist to make a wood material, they would do something like ‘crank up’ the specular, decrease this exponent value and lower the bump of that value against the power of blah-de-blah.
It wasn’t the slightest bit realistic. It didn’t use any math based on actual physical materials. It was, as John Carmack called it, a ‘dark art’ understood by few but painfully and forceably placed upon artists for no reason other than trying to ‘fudge’ what the material was, rather than correctly represent the material for what it is.
Roughness now means how rough something is. If it’s 1, it’s rough. If it’s 0, it’s not.
The same for every other channel. So instead of putting nonsensical and mathematically implausible numbers and figures to fake a material, you are making the *actual *material.
The biggest benefit from this is lighting and baking, as light bouncing around a scene will work correctly, instead of the old DX9 days when an artist would have to manually adjust everything, every material, because the level chief said to make a room brighter. After the room lighting was increased, all the materials didn’t work and the artist would get stuck in a loop, perpetually changing those nonsense values until they *looked *right. Now, you can change the lighting and the materials will react correctly.
This has made the job of an environment artist a lot simpler, as they are mostly now working with lighting more and more, rather than endlessly tweaking material values. They are being creative! A creative artist being creative? Who would’ve thought! It also gives them more control at the front end, as using tools/utilities from Allegorithmic and Quixel are giving artists complete confidence *prior *to integration, that texturing will yield near identical results. So, demonstrating proof of concept work prior to material creation, will mean a *significantly *more accurate representation of what the final environment will look like.
Enjoy this new world, it bears delicious fruits.