codersnotes

Dinosaur Input Device February 18th, 2009

When Industrial Light and Magic were making Jurassic Park, they had a bit of a problem. This was the early nineties, and there weren't very many animators around who knew how to use 3D animation software. (heck, there wasn't even that much 3D animation software around). They weren't sure they would be able to get experienced people to animate all these CG dinosaurs.

But what they did have was a lot of trained stop-motion animators. So they figured they needed to combine the two disciplines. And thus they built the Dinosaur Input Device.

In the beginning, Jurassic Park wasn't even going to be CG. The task had been given to Phil Tippett's studio. They were planning to use Go-Motion, which is like stop motion except the model is rigged with various motors. A computer records the position of the motors at each frame, and then can play the whole thing back again later. This means it can interpolate between the frames, causing motion blur on the final shoot.

They did some tests with this system, but Steven Spielberg was disappointed with the results. So ILM was given the task of trying to do a CG version.

The guys at ILM figured they could build a similar system to the Go-Motion armature, and hook it up to some software running on an SGI Indigo. They built some small mechanical dinosaur models (two T-rex, two raptors), and fitted them with a series of optical encoders to measure the angles of each joint.

The artist would then operate the model as if it were stop-motion, and the computer would show the matching CG wireframe skeleton on-screen. Once the data was in the animation package, it could be manually tweaked if needed.

You can read more about the DID in Pixar's paper.

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