Issue: Volume: 23 Issue: 6 (June 2000)

Hokey Smoke!




Rocky and Bullwinkle land in a live-action movie

It's been 35 years since "The Rocky and Bullwinkle Show" disappeared from network TV, and the once-thriving cartoon town of Frostbite Falls, Minnesota, home of Rocket J. Squirrel and Bullwinkle J. Moose, is now a desolate community crippled by years of reruns. Slash 'N' Burn Lumber Company has cut down the beautiful Frostbite Falls Forest, and in a little house at the top of the stump forest, Rocky and Bullwinkle subsist on ever-diminishing residual checks.

Bullwinkle: All this plot setup is wearin' me out. I'm going for a walk in the woods.
Rocky: But, Bullwinkle, there aren't any woods anymore.
Bullwinkle: Well, you don't have to tell me. I'm the chairman of the Frostbite Falls Society for Wildlife Conversation.
Rocky: You mean Wildlife Conservation.
Bullwinkle: What did I say?
Rocky: You said Wildlife Conversation.
Bullwinkle: Well, somebody's gotta start talking about these things.




On June 30, Universal Pictures will release The Adventures of Rocky and Bullwinkle, the first feature film starring the popular cartoon characters created by Jay Ward for television in the 1960s and in reruns ever since. Directed by Des McAnuff, the movie stars Jason Alexander as Boris Badenov, Rene Russo as Natasha Fatale, and Robert deNiro, a co-producer, as Fearless Leader.

In the movie, Boris, Natasha, and Fearless Leader have been brought out of syndication into the real world where they've taken control of a TV network they call RBTV (Really Bad TV). RBTV's programs are turning viewers into vegetables, and soon Fearless Leader will broadcast a program that hypnotizes people into voting for him as president. To stop that broadcast, FBI agent Karen Sympathy (Piper Perabo) must find Rocky and Bullwinkle and get them to New York City within 46 hours. In Hollywood, Agent Sympathy learns that to pull the beloved cartoon characters out of reruns, she has to greenlight the Rocky and Bullwinkle movie.

When she does, Rocky and Bullwinkle become 3D cartoons rather than real people. The three-foot tall Rocky comes up to Sympathy's hip; Bullwinkle towers over her at six-foot seven. Rocky speaks with the same voice that he had in 1960, thanks to Jane Foray, who provided his voice then and now. Keith Scott, the Narrator (who is never seen), provides Bullwinkle's voice.
Creating these smooth 3D characters with 'toon lines and a two-toned 2D look was a tricky task for ILM's effects team.




Industrial Light & Magic (San Rafael, CA) created the characters and the movie's other visual effects. All told, ILM produced around 600 shots, 400 of which have character animation, making it the second largest show done in CG at ILM (behind Phantom Menace).

Early buzz for the film is good, with the first reviews coming in positive. "It was the kind of silly but smart fun you would expect it to be-including the pithy narration," writes "Boris," an admitted Jay Ward fan, on the "Ain't It Cool News" Web site. And Entertainment Weekly's online summer movie preview says, "This probably won't be a tough sell for Universal, since the 1991 video release of the 1960s series was a success. Likewise, bringing the animated characters to the big screen was easy. A little green screen here, some ILM-designed shadows there, and suddenly the animated moose and squirrel were walking tall in an otherwise live-action landscape with real co-stars."

Easy? A little this and suddenly that? The effects crew at ILM might well answer "Bull....winkle." Rocky and Bullwinkle might look simple. But to get that look, 70-some modelers, animators, technical directors, software developers, compositors, rotoscopers, and painters faced a number of surprisingly squirrelly problems and enormoose challenges.

"A key issue for us was controlling the dimensionality of the characters," says Roger Guyette, co-visual effects supervisor. "The movie is in the Roger Rabbit tradition, except that Roger Rabbit is a hand-drawn animation and these characters occupy three-dimensional space and move in a three-dimensional way. Des [McAnuff] wanted them to interact with the people and the space they were in, but at the same time, he wanted to maintain the simplicity of the original characters." Recognizable elements from traditional animation-a simple color palette with big blocks of colors and lines around the characters-were used to give the 3D CG puppets a simple cartoon look. Simple idea, difficult problem.

"Rendering the characters in a way that didn't give them as much dimension as a 3D object proved to be more complicated than we thought," says Guyette. "And putting lines around the characters, something that seems trivial, was not." The simple shading style revealed problems with the way the skin moved, which had an impact on the way models were built, which had an impact on the animation,...and so forth. As for the lines-with 2D animation, an artist simply draws and colors the lines. For 3D characters, the lines have to be drawn and colored (rendered) by computer software, and that software had to be written. There are software packages that render 3D models as 2D cartoons, but Rocky and Bullwinkle had to stay 3D.
By making it obvious that lights affected the characters, the TDs helped integrate 'toons into scenes. Note Bullwinkle's extra-large shadow on the door.




"Doing any kind of 3D cartoon simulation forces you to rethink your whole production pipeline," says Ken McGaugh, technical director (TD).

"To flatten the characters yet retain some 3D detail was more of a challenge than we thought it would be," says Amelia Chen oweth, TD. "The physical lighting model we use tends to make 3D models look like puppets walking through 3D space." Although the original television characters were painted with one flat color, the effects team decided, after several tests, to start with a basic shader-say the orange-brown color for Bullwinkle's body-then split the color into two, using lights to create a bright side and dark side. "This gives us a little of the three-dimensionality of the model but it still looks a bit like cel animation," she says. "And having the bright and dark sides means you can light the characters so they look like they're in a scene."

To flatten the characters, the TDs began working with the line between the dark and light colors, using light shaders and surface shaders in Pixar's (Pt. Richmond, CA) RenderMan. The softer the line between dark and light, the more the model looks like a puppet; the harder the line, the flatter the surface appears. The TDs would also move the line to change the apparent dimensionality of the model.

These techniques helped solve one problem, but the large areas with flat colors opened the door to other problems. Take motion blur, for example, which is typically used to fit 3D characters into live-action scenes. Without motion blur, animated CG images strobe, but by its nature, motion blur removes lines. Because Rocky and Bullwinkle are rendered to look flat, they lose their form without their lines. "It was a huge issue," says McGaugh. "We had to come up with a proprietary technique that selectively motion blurs based on how fast something is moving so we could remove the strobing but preserve the edge detail."

A second problem created by the flat rendering popped up when deviations became apparent on the surfaces along the line between the two colors and in places where surfaces were "socked" (seamed) together. The creature development group had to solve this problem. In a process called "enveloping," this group stretches the surface skin onto 3D models, relates it to joints, and adjusts influences, or "weights," that control how the skin bends and flexes so that when the skeleton pulls the skin, the skin moves properly and doesn't tear. For photorealistic characters, character developers want skin to wrinkle at the joints, but Rocky and Bullwinkle needed to stay smooth to look like cartoons. To make matters worse, while photorealistic characters usually have elaborate textures that can hide unwelcome deviations, the squirrel and moose don't. "Because Rocky and Bullwinkle have flat surfaces that catch a lot of light, we could see a lot of deviation in their surfaces," says Aaron Ferguson, a so-called "zoo-keeper" or "creature developer."
Stand-in objects on set gave actors an eyeline but had to be meticulously removed by painters before the real Rocky and Bullwinkle could be added.




To help smooth these surfaces, the team used three approaches. The 3D models, which were created with Alias|Wavefront's (Toronto) PowerAnimator, were simplified. Procedural blur maps were painted on various areas. And finally, Ferguson's team adapted a technique first applied by Aaron Pfau to smooth a shark's skin in Deep Blue Sea: On low-resolution polygonal meshes created for the characters, they used ILM's cloth simulator to distribute enveloping weights, and then applied that result to the higher-resolution, B-spline models of Rocky and Bullwinkle to redistribute their enveloping weights more evenly. The result is smoother surfaces. "It happens as part of the rendering pipeline-we don't see the effect until it's rendered," says Ferguson.

Meanwhile, the animators are moving geometry, which causes the skin to move, and that sometimes creates problems for the creature development team as well. "It was hard to create lip sync that looked nice without getting wrinkling that the enveloping group had to fix," says David Andrews, animation supervisor.

In fact, it was difficult to create lip sync at all using a model designed to match the 2D cartoon. For example, Bullwinkle's huge nose kept getting in the way. "It was hard to see his mouth," Andrews says. "We had to find ways to give the im pression that his jaw was actually forming sounds." For facial animation, the crew of 29 animators used ILM's Caricature software; for body animation they used Avid's (Tewksbury, MA) Softimage 3D.

Making the characters walk was no easier. "Rocky didn't have much of a neck, so you had to be creative to get attitude out of his little squirrel body," says Jenn Emberly, computer graphics animator. "And then we had to keep his little short legs in pace with Bullwinkle."
Trying to animate 3D models originally designed to be 2D cartoons was a challenge. Here, little Rocky tries valiantly to keep up.




"Rocky is low to the ground, and his knees go out, which gives him a bowlegged look, so when he has to run as fast as he can to keep up, he gets this flippy thing happening with his feet," says Andrews. "It's a very funny walk."

As for the moose: "Bullwinkle has these big pontoons for feet," Andrews says. "He can't high step with his knees because Des [McAnuff] didn't like it, so he has to shuffle a little bit. What else can you do when you're working with rotations of real joints?"

Guyette explains that McAnuff wanted the cartoon characters to be in keeping with the real world and not too cartoony, and he wanted the actors and some of the stunts to be more cartoony than the real world.

"It's ridiculous stuff, and it's all downplayed," says Andrews.

One area where the animators did cut loose and create more cartoon-style animation was with Bull winkle's eyes. "We did some stretching and squashing," Emberly says, "and goofy stuff like rolling eyes."

That bit of fun for the animators created fresh chal lenges for Ferguson's creature development crew. To avoid creating new eyelids to match each new shape for Bullwinkle's eyes, the R&D department created a UV deformer that allowed an eyelid to slide over the surface of an eye regardless of the eye's size or shape. "Otherwise, we would have had to create a zillion blink shapes," Ferguson says.

The creature developers also added secondary animation using simulation software to animate Bullwinkle's robe in a courtroom scene, for example, and the flaps on Rocky's cap when he's flying. "The simulation does a little flutter over the top of the geometry," says Emberly. "I think it really helps the look of the shots, all those little details."

These details all helped the animation and effects team strike a balance between cartoon and realism, and each required solving interesting problems. But one of the most interesting challenges of all was creating and coloring the lines that give the characters their cel animation look. For this, Mayur Patel, an R&D TD, created a proprietary, programmable application now called "Toonline." McGaugh customized it for this production. And Scott Frankel, 2D supervisor, took the result and fed it to a set of programs written in ILM's custom composition program called Comptime. "We had literally all the control we could want without having to paint the lines, which was great," says Michael Bauer, a CG supervisor.

Many nonphotorealistic rendering software tools use edge detection, which typically generates lines for cartoon rendering using a renderer's color image output. To reduce such problems as flickering, Patel wanted cleaner lines than he could get with this method. Thus, rather than starting with the TIF file that Ren derMan outputs, Patel's Toonline software interrupts the rendering process so that it can work with geometric data from RenderMan. This geometric information includes such things as the depth between the camera and the surface, surface normals-which tell which direction a surface is pointing when you look at it-and so forth. Then, using algorithms and heuristics-sets of decision-making rules-Toonline sorts through that information and decides where to put lines.

"If you do this as a 3D process, you're at the mercy of a 3D engine that's making decisions based on photorealistic rendering," Patel says. "By stopping in the middle to work with the geometric information, we can be more precise."

"Every shot needs a bit of cleanup, but it's painless," says McGaugh. That's partially because rather than creating one process for all conditions, the sets of rules can be changed on a scene-by-scene basis to give the effects crew and the director artistic control. "The way the software is written, TDs can write line detectors almost like they write shaders," he says.
For handshakes, the TDs and compositors needed just enough motion blur to sell the shot without eliminating defining 'toon lines.




At the end of the process, three "passes," or separate files, are produced. A color pass has the shaded bodies of the characters; a second pass has a black-and-white, alpha-channel image of all the lines; and a third pass isolates specific parts of the models-Rocky's cap, for example, or Bullwinkle's antlers-so that lines can be selectively thickened or thinned.

It's up to Frankel's compositing group to put the pieces together with the live-action photography. Frankel's programs can automatically tweak line colors using the character's interior color, the live-action background behind the character, and parameters entered by compositors. In addition, sliders and controls can be assigned to the isolated parts for fine-tuning. Toonline renders lines as darkened versions of interior colors, and centers lines on edges. Frankel's programs extend that interior color to the edge of the lines, and mixes into the line color small amounts of colors derived from inverting and flipping the background hue. Thus, in a top-lit scene the color added to the line around a character might be darker at the top, lighter at the bottom and hue-inverted throughout. In addition, compositing programs find dark areas based on a preselected luminance value and brighten Toonlines in that area. If Bullwinkle's white-gloved hand is partially shadowed, lines in the shadow would be automatically brightened, but lines in the light would stay darker.

"There were so many details," Frankel says. "We just had to walk down the path and find solutions to problems we encountered on a case-by-case basis. The unsung heroes, though, were the roto and paint artists. When they have done their job well, you never know they were there." Similarly, there were many invisible visual effects in the film. In one scene, for example, a dramatic camera move on Sixth Avenue in New York City looks real but could only have been done with visual effects.

"When you look at these cartoons you automatically think it should be simple and straightforward," says Ferguson. "I think this show took us all by surprise." All but Agent Sympathy, that is.

"I suppose you're wondering why I've picked you for this mission," says FBI director "Cappy" Von Trappment (Randy Quaid) to Agent Sympathy.
She answers, "Yes, Sir."
"Well, first of all, you're the star of the movie," he says.
She replies, "Thank you, sir, but the real stars are the special effects."

Barbara Robertson is West Coast senior editor for Computer Graphics World.
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