Jeff Russell, the engineer and author of Marmoset Toolbag posts a great article covering the basic theory behind physically based rendering with a look at how a PBR system works and how it differs from a traditional rendering system.
Physically-based rendering (PBR) is an exciting, if loosely defined, trend in real time rendering latelyJeff Russell –marmoset.co
There are a great many components that come together to calculate and render something physically, it is not just how the rays are calculated. Other components such as lights, surfaces, materials, cameras, and sampling all come together to offer physical realism.
Jeff offers a condensed look at physically based rendering, touching one the key points such as how diffusion and reflection are derived in a physically based rendering system as the foundation for how the light transport is calculated.
There are quite a few bits of great info here, so make sure you check out the entire post for the Basic Theory behind Physically-Based Rendering here.
In continuation to Jeff’s Physically Based Rendering Basics article, Joe Wilson has a companion tutorial covering Physically Based Rendering. Covering some PBR frequently asked questions, the inputs and terminology behind energy conservation, micro surface, fresnel, AO and cavity, Joe also shows how to find material values for getting your surfaces looking like the real thing.
Joe takes a look at the basics of art content creation and some of the ideas behind physically based rendering standards, and takes the time to call out some common misconceptions behind physically based rendering. There are some great resources in the article, so be sure to check out the tutorial for Physically based rendering here.
About Marmoset Toolbag
Marmoset offers realtime physically based rendering and material editing providing a full featured real time material editor and renderer all in one package.
Recently ToolBag underwent an update to include a physically accurate renderer that is powered but the computer’s GPU to provide realtime rendering to both OSX and Windows platforms. To learn more about Marmoset ToolBag, check the features page here: Marmoset ToolBag 2, the Essential Realtime Artist’s Toolkit.