ABSTRACT
This chapter presents an overview of scanline and ray trace rendering, and an overview of Physically Based Rendering (PBR) systems and their unique features. It also provides an introduction to render passes and Arbitrary Output Variables. In general, the physical accuracy of a PBR system is dependent on the following calculations: diffusion, reflectivity, transmission/refraction and bidirectional reflectance distribution function. The chapter reviews common rendering and lighting systems that use PBR. This is by no means an exhaustive list, but it does include systems that are commonly used. Some 3D programs and 3D renderers provide a complete sky lighting system that emulates outdoor, sun-lit lighting. A render pass breaks a single shot into multiple renders with separate objects or separate shading qualities. The passes are then recombined in a 2D compositing program. The recombination may fall to the lighter or to a specialized compositing team or department. The use of render passes is common for visual effects and feature animation work.
