In this talk NVIDIA’s Eric Haines runs through the basics of ray and path tracing. To begin, he defines a ray and notes how it is useful for different operations in computer graphics. Rays can be cast to test for shadows, for example. In 1980, Whitted introduced the idea of recursive ray casting, known as ray tracing. Cook and others in 1984 explored how bursts of rays could create more elaborate effects, such as soft shadows and glossy reflections. Kajiya introduced the Rendering Equation in 1986, showing how it could be solved using path tracing. This whole field of ray tracing takes an extremely simple primitive - the ray - and explores how to most effectively use it to create images of unparalleled realism.