A term that you often see here in Blender 3D Architect, especially when we share a collection of free textures is PBR. That is an acronym for Physically-Based Rendering, and a significant amount of renderers supports PBR. Among them, we can list Cycles.
Do you want to go deeper in your understatement about PBR and how to create materials for Cycles? Or any other 3d software that supports PBR?
A great resource to expand your knowledge about PBR is this free eBook from Wes McDermott, which is a technical artist at Allegorithmic. The same company that develops the popular Substance Designer, among others.
To download the eBook, you can visit the Substance Academy. There you can download a PDF version of the eBook.
The book is not new, and the first edition dates from 2014. In all those years it received a lot of updates and improvements, still maintaining a condensed amount of information. With a total length of about 15 pages.
Does it worth the read? If you don't have any idea of how a PBR material works, it might give you some insights on why you would connect some nodes in a certain way.
They won't deal with Cycles or Eevee in the eBook, but give you an explanation of how each concept works. You will see a lot of familiar concepts there like Disney's principled reflectance model. The model that later gave “birth” to the Principled BSDF shader in Cycles.
You will notice that this eBook is Volume 1. Is there a volume 2? Yes, there is a volume 2. But, it will start to deal with the creation of materials in Substance Designer. If you want to get the free PDF for volume 2, here is the address.
What if you don't have any PBR textures to put the theory into practice? Here are a few free libraries we posted here in Blender 3D Architect:
