In this second chapter of the Unreal Materials Masterclass series, we’ll explore the concept of PBR and learn how three simple values can be used to recreate almost any physical material in the real world.
https://dev.epicgames.com/community/learning/tutorials/65G2/unreal-engine-fortnite-unreal-5-8-materials-masterclass-chapter-2-physically-based-rendering-pbr-basics