What’s the Difference Between Ray Tracing, Ray Casting, and Ray Charles? (.PDF Download)
Feb. 2, 2016
Like ray casting, ray tracing “determines the visibility of surfaces by tracing imaginary rays of light from viewer’s eye to the object in the scene.”1
Ray casting is faster than ray tracing.
Ray casting is faster because its world is limited by one or more geometric constraints (simple geometric shapes); a ray-tracing world can be almost any shape.
You can read the article online.