What is Ray tracing?

Image of a ray traced teapot floating over a checkerboard. A stereotypical ray tracing scene.

“Ray tracing is one of the most popular methods used in 3D computer graphics to render an image. It works by tracing the path taken by a ray of light through the scene, and calculating reflection, refraction, or absorption of the ray whenever it intersects an object in the world - hence the name. For example, starting at a light source, we may trace a ray of light to a surface, which is transparent but refracts the light beam in a different direction while absorbing some of the spectrum (and altering the colour). From here, the beam may strike another surface, which is not transparent and so the light undergoes both absorption (further changing the colour) and reflection (changing the direction). Finally, from this second surface it may be reflected directly into the virtual camera, where its colour contributes to the final rendered image.”

Taken from the wikipedia entry for ray tracing.

“The Persistence of Vision Ray-Tracer creates three-dimensional, photo-realistic images using a rendering technique called ray-tracing. It reads in a text file containing information describing the objects and lighting in a scene and generates an image of that scene from the view point of a camera also described in the text file. Ray-tracing is not a fast process by any means, but it produces very high quality images with realistic reflections, shading, perspective and other effects.”

Taken from the povray documentation.


  1. Wikipedia Article on Ray tracing
  2. The comp.graphics.rendering.raytracing Frequently Asked Questions (FAQ) List (part 1/2)
  3. The Persistence of Vision Raytracer
  4. The Internet Ray Tracing Competition