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On Being Crew for Fantasia 2000

Stanley B. Lippman

I was asked to reminisce about my experience as a software technical director on the Firebird segment of Disney's Fantasia 2000 in the special effects group. They're the group that puts the twinkle in Mickey's eyes, literally. This group was a mix of artists who draw by hand and artists who use computer graphics. I wrote software to help the graphic artists work, mostly in Perl, tkl and tsch under IRIX, the SGI UNIX OS, although I did get to extend the Houdini C++ class framework.

I became pretty good friends with Tim, my officemate, and Michael, our primary CGI animation artist. We used a program called Houdini for the production—my coworkers had used it on the Hydra animation in Hercules. I couldn't make heads or tails out of Houdini from an artistic standpoint, although my boss was nice enough to let me sit in on the training.

The traditional effects people work differently than the character developers do. In the character stream, there are lead animators who establish the look of the character in model sheets that detail every perspective and annotate how each aspect of the character should be drawn. She may draw the keyframe sequence in a very freehand manner. The clean-group turns the freehand drawings into line art, after which another group, called the in-betweeners, fill in the necessary drawings to connect one keyframe to the next. (This has now all been replaced with computers.)

But the effects guys have to provide every frame. I watched one artist draw the lava. He worked at a light table, constantly flipping sheets back and forth to gauge the continuity. All he drew were little circles and wave-like ridges for days and days. We had one artist from Digital Domain who had worked on the CGI lava for Inferno. He was pushing for the Firebird lava sequence to be replaced by a CGI element. There were often such arguments between the traditional advocates and CGI.

There are lots of antagonisms in the industry. Motion capture, in which a person is wired up and her movements captured as a set of coordinates, upset many of the traditional computer animators with the complaint, "where's the art in that?" Each step in automating a previously human-executed procedure seems to always be shadowed by that question.

The Firebird combined traditional drawing and CGI graphics remarkably well. For example, the Elk in the segment was hand animated, but its antlers were CGI elements. To match the two elements, I wrote a Perl script to capture the Disney camera values and translate them into a procedural camera entity that could be made the default camera within Houdini. Using the Houdini particle system, Tim did the grass streaming from the Sprite as she flies through the forest. He also did the butterflies that randomly flit alongside her, as well as the red poppies that pepper the screen. Michael animated the gorgeous bursts of tree blossoms, the sadly sashaying ashes, and the shimmering sunlight in the final scene (that was later discarded).

I was invited to attend the first presentation to the special effects group of the climatic rebirth scene. The directors reviewed the storyboard and the concept art, telling us the story and the general feelings they wanted conveyed by the effects. This was again going to be a mix of hand-drawn and CGI effects. But, and this startled me at first, no one really knew how to make this work. The meeting was intended to kick-start the process. As a programmer, it surprised me that there wasn't already a procedure in place for this. After all, we were already in production. I was interested in how much the folks leading the team relished the absence of structure and the challenge of creating this crazy scene.

I was asked to try out a special tree-growing Houdini module. The tree-growing algorithm lets you set variables for branching and trunk length and direction. I remember walking out of the building and looking at the trees as if I had never seen them before. I needed to see how they grew and the space they occupied. In practical terms, I was a complete failure. But it was a glimpse of another way of being in the world. That was my most special moment in animation.

It's a different kind of life fretting about how to stream grass from out of the Sprite's arms than working out an algorithm for translating C++ and implementing it.

It was a kooky kind of thing to do, all in all, but nothing has ever approached the wonder and camaraderie of being crew. When I was at Siggraph last year, I bumped into some of the Firebird folks; they were making a CGI movie in Toronto and asked if I would like to be on crew. Of course, I do. But I told them no.

Stanley B. Lippman is an architect with the Visual C++ team at Microsoft. He began working on C++ with its inventor, Bjarne Stroustrup, in 1984 at Bell Laboratories. In between, he worked in feature animation at Disney and Dreamworks and was a Distinguished Consultant with JPL. He also writes the Pure C++ column for MSDN Magazine.