Twixt animation system

Twixt was a 3D computer animation system created in 1984 by Julian Gomez at Sun Microsystems.
It featured keyframes and tweening in a track-based graphical interface, and was capable of realtime wireframe playback. An Apple Macintosh port, called MacTwixt, was the first known 3D animation software to be released for the Macintosh, and was used by Apple's Advanced Technology Group (including future Pixar principals John Lasseter, Andrew Stanton, and Galyn Susman) to create the 1988 short film "Pencil Test". Maintained as open-source software until 1987 by a research group at Ohio State University, Twixt ultimately saw use in approximately 800 groundbreaking animated television and advertising projects.