a.k.a. Harrold the Flying Sheep

What is Flubber? In the 1961 Disney movie, Flubber was the startling discovery of an absent-minded professor, a wonder-goo that defied gravity. When applied to objects or people, it enabled them to fly through the air at dazzling speeds. In its latest incarnation, Flubber has become a digital wonder-goo capable of stunts that only the animators at Industrial Light & Magic could conjure up - once they realized the possibilities of metaclay. The film marks the first time that metaclay, generally considered a modeling tool within SOFTIMAGE®|3D, was used this extensively for character animation.

"It was great, we could make the character turn into and do literally anything. This could not have been done with a regularly built model made out of patches or polygonal meshes," states Lead Animator Philip Alexy, who along with a team of animators was responsible for giving life - and a great sense of rhythm - to some goo. "Another thing that metaballs gave us was the organic shape that polygonal meshes or B-splines sometimes don't provide. Overall, polygonal meshes are fairly facetted, but the way the balls interact with metaclay provided a nice organic feel, which the director really liked."

Flubber’s beginnings were far from auspicious - as begets any blob, really. "When we first started, we had a maquette of a pear-shaped blob," recalls Alexy. "We had an inkling that it was supposed to do a dance sequence at some point, so my basic design was to try to get this little pear-thing to work." Jeff Light, who developed some basic Flubber character designs with about six metaballs in it, did the initial R&D stages. Then Alexy took off on Light’s ideas and the animators ended up with a character composed of almost six times as many metaballs.

Alexy delves further into the pre-Flubber stage: "We had thought of doing something where we could use B-spline patches that we could shape animate over time. But, that wasn’t practical because Flubber changed so much within a sequence that it would have been too time-prohibitive to model all the different forms. Even when he was just a little blob he changed so much that to do it using patches, shape animation and lattices just wouldn't work."

Since the Flubber character was composed almost entirely of metaballs, the animators could easily turn him into anything from a pair of lips to a tail-wagging puppy to a hip-shaking mambo dancer. In addition to Softimage, ILM developed several custom effects to turn a blob into everything that blobs could possibly become within the animators’ collective imagination. Several Flubber models were developed: the Basic Blob, a male and female Actor-Flubber, a Scare-Flubber, a Puppy-Flubber, a Fingers-Flubber, a Bubble-Flubber and several others - each more difficult to pronounce in rapid succession.

Modeling on the Fly

Throughout the project, Softimage was used as both a design and animation tool, enabling the animators to develop new models on the fly. Alexy would hand his team an Actor or a Blob-Flubber, and they would take those basic models and create new characters for every scene.

Metaclay also allowed the animators to hide structures within the clay itself, which made it easy to do 3D morphing without having to create two different scene files. There's a point in the film where Flubber is in a pot and then turns into a pair of lips. To create this effect, animator Andy Wong took the basic Blob-Flubber and created lips, which were hidden inside the metaclay structure. So, when the head of the Flubber flips back, the hidden lips could be brought out.

Alexy cites another sequence featuring this technique: "One scene that I animated involved hiding a scaled-down puppy inside the basic Blob-Flubber. When Flubber had to change, I'd turn it, shrink it and expand the puppy out. Usually with something that's shape animated like this or changes into something else, we have to do a quick-cut between two different models or scenes. We couldn't combine everything in one scene file. We also didn't have to do any B-spline modelling because metaclay created surfaces on the fly. We could hide anything in there, as long as it wasn't outside where it would create the surface."

Even though the animators used metaballs for the actual Flubber, they didn’t write a shader that would put bubbles inside the character. Instead, they chose to put anywhere from a dozen to a hundred B-spline spheres inside. "We could then move those splines around and hook them up to the skeletal structure of the Flubber so that they'd move independently," explains Alexy. "There were actually times where the director wanted us to move them independently to reflect the kind of emotion that Flubber was experiencing."

No Buts About It

"So, we built the Blob-Flubber, did a test sequence and they loved it," continues Alexy. "Then we went into more detail with the Mambo Sequence, which is a huge dance number in the film, where two Flubbers dance with each other. I created an Actor-Flubber with arms and legs, which was a hybrid of the design for the Blob-Flubber and rigid IK models that use skeletal structures for arms and legs."

The Actor-Flubber was featured in the test sequence called ‘The Coffee Pot" where the character slides in, changes into a smaller Flubber, and begins some unique dance moves. But, Alexy describes it best: "The little Flubber jumps forward, butt in the air to the camera, shakes it to the left, shakes it to the right, jumps in the air, spins, falls into a blob and then goes ‘Yeah!’ When we showed the test to [Producer] John Hughes he just went nuts over it! I had to actually scale the buttocks out, take them off the body and jiggle them separately. And, with metaclay, it was easy do that - it’s a great thing - there’s no modeling involved! If I had had to do that with a B-spline, I would have had to get a modeler to model butts and then shape-animate to that. But this was metaclay and the animators had complete control!"

Pure Animation Value

Overall, Flubber was a character done for its pure animation value, taking the animators back to their roots. "I have never worked on a project that has been quite like this, where we could change the model in its fundamental sense," states Alexy. It was great because it was pure animation - it wasn’t trying to be realistic because Flubber could be anything! Our modelers here are great and work between modelers and animators is very integral for shows like Men In Black, Lost World or Mars Attacks, but with Flubber we practically didn’t need modelers since the animators created the shapes and had direct interaction with what those shapes would become in every frame. They didn’t have to take on a pre-made model and be limited with that. They could completely cut loose. It was basically like drawing within 3D."

In fact, the only time a modeler was needed was for the face-stretch sequence, which had to be done with B-splines. The whole set-up of the shot was because Robin Williams [Professor Brainard], unscripted, began stretching some Flubber goo between his hands, putting it over his face, making expressions and doing some character voices.

Says Alexy: "Initially, we thought we’d do this with metaclay, but the density of the metaclay needed to create a nice, smooth surface would be in the order of thousands. So we decided to do it the regular, old-fashioned way. We had a cyberscan of Robin’s head and our modeler, Tony Hudson, not only animated the shot, he took the cyberscanned data and modeled a sheet of Flubber. Then, using shapes, he interpolated a shape coming out of the sheet. This shape-animated sheet of B-splined Flubber was then matched to Robin’s hands and to all his actions. So, when he puts his face to the Flubber, you can actually see the contours and stretching. When Robin pulls it off his face like an accordion, Tony scaled the sheet and animated more face shapes to follow Robin’s facial movements when he was doing his little voice-over. And at the end, it just pops back into a Flubber.

It was a unique animation project overall, but Alexy singles out a scene which stands out in his mind: "Animation-wise, my favorite shot was the Puppy-Flubber because I have a Toy Fox Terrier named Frederick who weighs only about four pounds, a little itty-bitty guy who’s just this huge adrenaline gland. This was exactly the kind of feeling that they wanted for the Flubber character. I took video reference of Frederick and when I animated the shot, I poured all that feeling into it. It’s identical to how Frederick moves and acts. The animators even did his barking sound and had the Puppy-Flubber shaking its little butt just like Frederick does when he wags his tail."

It’s this subtlety combined with wacky character animation that underlies the film. "With Softimage the subtle stuff comes very easily," says Alexy. "We can take a broad-action creature like Flubber and change him into a nuanced puppy character very easily. And those small details become more obvious when you’re animating things like a small dog, where gestures like twitching or cocking its head a little bit or its waggling tail create personality. This can all be done wonderfully using Softimage."

Although Alexy created most of the models for Flubber and did a handful of scenes, he is quick to point out that this project was a group effort on a large scale. "Everybody worked together - from the roto artists, to the matchmovers, software people and TDs. Flubber would not even exist, unless everyone involved had done their job as well as they did.

"And, I don’t think that any of this would look nearly as good as it does if it wasn’t for Softimage. It’s doesn’t make you compromise you animation ability. It really lets you go through with all your ideas. It’s not so much a computer tool which does things for you as a pencil tool, which you direct to do things. So it was this combination of many talented people, building on each others’ work and the technology that we had to work with which all came together so well."

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