Eric Graham

The Juggler

In November of 1986, early in the history of the Amiga computer, Commodore released a new demo animation featuring a robot juggling three mirror balls. «Juggler» was a continuously looping sequence of 24 full-color frames, with matching «clink» sound effect, playing at 30 frames per second.

This demo really showed off the Amiga's superior graphical capabilities. The way the 3D environment was accurately and dynamically reflected in the glass balls hadn't been seen before. It was one of the earliest full-color 3D raytraced animations rendered and displayed on a personal computer. In fact, I know of no earlier example than this famous demo by Eric Graham.

Eric rendered the frames in a raytracer he wrote called «ssg», a Sculpt precursor. The rendered images were encoded in the Amiga's HAM display mode and then assembled into a single data file using a lossless delta compression scheme similar to the method that would later be adopted as the standard in the Amiga's ANIM file format.

Juggler was an astounding demo in its time. Many people were inspired by Juggler, and by the Amiga animations that followed, to pursue a career in 3D graphics. Nothing like it could have run on any other stock personal computer in 1986.

In fact, Eric recalled recently, the Commodore legal department initially «thought it was a hoax, and that I'd done the animation on a mainframe.» He sent them his renderer so that they could generate and compile the frames themselves.

The image data of the original Juggler is stored in a unique file format that was never used for any other animation. In order to preserve The Juggler and make it available to a larger audience, Ernie Wright extracted the image data from the original file and recompiled it into a Windows AVI.

© Walter Randelshofer. All rights reserved. Animations used under permission.