3D rendering is the 3D computer graphics process of automatically converting 3D wire frame models into 2D images with 3D photorealistic effects on a computer.
Ray tracing is a method for calculating the path of waves or particles through a system. The method is practiced in two distinct forms:
1. Ray tracing (physics), which is used for analyzing optical and other systems
2. Ray tracing (graphics), which is used for 3D image generation.