The comprehensive PBR guide
Volume 1: The Theory of Physically Based Rendering
This is the first of two volumes, which focuses on the theory of physically-based rendering and shading.
It’s important for us to understand how light rays interact with surface matter because our job as texture artists is to create textures that describe a surface. The textures and materials we author interact with light in our virtual worlds and the more we understand about how light behaves, the better our textures will look. In this first volume, we will discuss the theory behind the physics through which physically-based rendering models are based upon. We will start with a light ray and work up to defining the key factors for PBR.
https://www.allegorithmic.com/system/fi ... _Vol.1.pdf
Volume 2: Practical Guidelines for PBR Texturing
In this second Volume, we discuss the practical application of authoring PBR textures and provide a set of guidelines that are based on the foundations established in Volume One.
We will begin by redefining PBR from an artistic perspective. From there, we will discuss the metal/roughness and specular/glossiness workflows to address the principles and guidelines for authoring physically-accurate maps.
https://www.allegorithmic.com/system/fi ... _rev05.pdf
Basic Theory of Physically-Based Rendering
https://www.marmoset.co/posts/basic-the ... rendering/
https://www.marmoset.co/posts/physicall ... u-can-too/