If you are interested in truly knowing how the Unreal Engine PBR system works theoretically and practically, this is your course. I will cover the most important material inputs and the physics and logic behind them. This will help you when bringing external assets into UE or when authoring your own PBR assets.
I want everybody to understand why PBR materials work they way they do and that they behave in that way due to the physics of light in which the PBR implementations are based.
We will explain these concepts in an easy to understand manner and with practical examples in-engine. After this series of videos you should no longer be afraid of PBR terminology and the physics and math behind the PBR implementations.
https://dev.epicgames.com/community/learning/tutorials/Yx3q/unreal-engine-physically-based-rendering-pbr-explained-in-depth