PBR and You
Once upon a time, Environment Artists created textures and materials. They would create something that looked nice in a given lighting situation, but then if the lighting was different, those same materials might look terrible. So they might make duplicate textures with a slight variation to them, or make new duplicate materials in an attempt to come up with something that might work better with that new lighting environment or time of day. This could become annoying, as there would start to be duplicates all over the place that were a waste of space and shouldn't be needed in the first place, if the only purpose is to work better with lighting.
This could sometimes result in a sort of "battle" between the Environment Artists and the Lighting Artists, with one side blaming the other for why things don't look right.
Although there are many benefits to the PBR system, one of the main ones from the point of view of lighting, is that it creates a more stable, uniform method of materials and material lighting, thereby helping to resolve said battles.
So what is PBR exactly? PBR stands for Physically Based Rendering. What's meant by that is that the goal is to create a rendering system that is actually based on the real world (the physical world) and how various material attributes respond to light in the real world as well. We're talking about things like gloss and roughness, specular highlights, and how normal maps respond to directional light, etc. Think of it as away to try to get everyone to speak the same language.
(To make things even more confusing, there are 2 "types" of PBR: "Metalness" and "Specularity". Different programs and game engines use different methods, and you'll need to know which you're using to get things to look right.)
Here's how that sort of plays out in a game studio workflow/environment:
Most studios these days seem to follow the same steps in a process. I've seen this at a number of places, and can only assume it's fairly standard by this time.
1) A master "material test" level is built, that contains lots of different objects with PBR materials applied. These materials will run the gamut from metals like chrome, gold, copper, etc. to different types of wood, stone, bricks, glass, concrete, etc.
2) When an Environment Artist creates a new material, they apply it to an object and place the object in this test level. The test level should have a system where it's easy for the Environment Artist to switch back and forth between different times of day, like early morning, noon, late sunset, midnight, etc. If the object looks good in the test level at any time of day, the Environment Artist is done.
If that same object is now placed in the actual game level, and it does not look right, the Environment Artist can now happily blame the Lighting Artist, because the Lighting Artist is probably at fault. It's your job now as the Lighting Artist to figure out why things don't look right in the game level, even though it looked right in the test level at all times of day.
And that will at least in part be done through the placement and adjustments of lights.
