In real life, light comes from every direction and is reflected, scattered, and absorbed by every surface imaginable.
Replicating light’s natural behavior in computer-generated images and footage has always been a holy grail for animation, visual effects, and game development studios—path tracing brings this goal closer than ever.
Path tracing represents the evolution of older techniques such as rasterization, where an image is built from a single source of light, and ray tracing, which determines what's visible at several points from different directions in the scene, letting you program more realistic scattering and impacting of light.
Path-tracing rendering applies an algorithm to the illumination properties of the whole picture, determining the amount and quality of light projected toward the viewer for every pixel in the image. The computational power behind it lets you include further effects such as depth-of-field focus changes and motion blur.
Recently, new tools have emerged that put real-time path tracing into the hands of animators and designers; it will be a common feature in film, tv, and games over the coming years.