What is Path Tracing? Disney Explains…

Blake Harris 08.05.2015

Between last year’s Big Hero 6 (which won the Academy Award for Best Animated Feature) and next year’s Zootopia (slated for release in March 2016), Walt Disney Animation Studios appears to be back on top of their game. While memorable characters and intricate storytelling are both certainly part of Disney’s formula for success, these two films also noticeably benefit from an impressive degree of animation technology. In particular, a powerful tool called the Hyperion renderer. And to help explain why this is important, and how its capabilities can best be utilized, Disney recently produced this beautiful, filmstrip-style video:

Highlights from the Video: 

1) “Light is like a billiard ball on a pool table.”

Light is like a billiard ball 

2) “But that was just for a single ray of the sun. Just imagine it for millions.”

Millions of Rays

3) “The process for building this image inside the computer is called rendering. These calculations take time and can often require more than what the computer is capable of.”


4) “In order to produce a more efficient render, we use a method called path tracing. This method reverses the process and considers only the light paths that are visible to the camera. This way, every single relevant ray of light is accounted for.”

Relevant Rays

5) “Camera Rays don’t emit one at a time, instead millions of rays are emitted across the entire camera frame. But, again, one hit isn’t good enough. We need to do multiple hits to make things look natural.”

Multiple Hits

6) “Because some rays are traveling in the same direction and have similar characteristics, we can batch them together and place them on the processor to be calculated at the same time.”



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