Issue: Volume: 24 Issue: 4 (April 2001)

Jungle Fever




When things get too hot for Sheena star Gena Lee Nolin, a digital stunt double swings into action

By Karen Moltenbrey

At one time or another, most of us have thought of our work environment as a "jungle." For Gena Lee Nolin, that description couldn't be truer. A former Baywatch star, she has traded in her surf surroundings for new roots as Sheena, a modern protector of the jungle. In the hour-long live-action television drama named for the character-who was raised in the jungle-Sheena uses an ancient tribal secret to morph into a hawk, leopard, elephant, and various other animals in her quest to keep the wilds safe and free.

Sheena's shape-shifting isn't the only transformation that occurs during the show. In situations that are especially dangerous or impossible to accomplish otherwise, Nolin is replaced with a stand-in-a 3D digital double. "We've created a 3D version of Sheena to act in complicated situations, like running through a herd of wildebeests, jumping across a river, or scaling a cliff," says Art David, visual effects supervisor at Victory FX Animation in Orlando, Florida. "There's a lot of interaction between Sheena and wild animals, and many scenes would put [Nolin] or even a stuntperson too close to the animals for comfort," adds Douglas Schwartz, co-executive producer at Corsica Productions, the show's production company.

Set elements and backgrounds also are digitally replaced or composited. Although the program's geographical focus is a lush African jungle, the episodes are filmed on sound stages and locations at Disney MGM Studios in Orlando. Photorealistic computer-generated images and some stock film footage are often added to the scenes. "We're trying to build a specific universe for this show, which encompasses a lot of fantasy aspects, and it's difficult to do many of the effects practically without having the budget or time schedule of a feature film," explains Steven Sears, co-executive producer at Corsica. "So we decided early on to do as much as we could with CGI."
Victory FX Animation created a realistic digital double of Gena Lee Nolin, the star of the live-action television series Sheena. The 3D model is used in scenes in which the action is too dangerous or the feats too difficult for Nolin to perform. (Images c




Based on the 1930s comic book "Sheena the Jungle Queen," the Columbia TriStar syndicated production began airing this past fall. Of all the digital effects in Sheena, the most stunning by far are those involving the 3D character. First hired by production facility Disney i.d.e.a.s. to do the morphs only, Victory FX expanded its role after broaching the idea of a digital Sheena. Sears notes that the digital Sheena was so convincing that it appears in the show's opening title sequence.

For the computer-generated Sheena, a team led by David used a Cyberware scanner to create a digital reference model of the actress. Next, Joe Spadaro, modeling supervisor, built a NURBS framework around the scanned data using Alias|Wavefront's Maya, then converted it into subdivision surfaces to make the model seamless-from the head to the toes. For further accuracy while building its model, the group used reference photos taken of Nolin from all angles as well as precise physical measurements.

The photos and measurements were especially valuable when the group constructed the character's body, which was done in Maya running on a variety of SGI Octanes. "We tried to get a complete cyberscan of her entire body, but the scanning hardware was not readily available on the East Coast, and time was an issue," says David. "Because we had to act quickly, we decided to use a cyberscan of her face only and then hand-model her body."
Animators at Victory FX also create the shape-shifting effects that appear in Sheena when the star morphs into an animal such as an elephant.




The character model is a work in progress. "Our ultimate goal is to have it undetectable from the live-action character in waist up, medium shots," says Spadaro. Currently the digital character is used only in long shots, where the model may take up half the screen at most.

While the accuracy of the model was paramount, animating it in a realistic way was also important, since the digital character had to perform stunts that required a great deal of agility. "The model had to match the character in the scene as well as what was happening in the scene," notes David. "Digital Sheena couldn't look plastic or act in a plastic-like manner; she had to move like a mystical jungle queen." To accomplish this, character setup supervisor Heather Thomson established a complex skeletal structure for the model that closely mimics that of an actual human. She then set up controls for manipulating the character's movement more easily.

For textures, the group scanned reference photos of Nolin taken at high resolution, then applied them to every surface on the model using Alias|Wavefront's Studio Paint. With Studio Paint and Adobe Systems' Photoshop, the artists touched up the textures so they looked even more photoreal. "With Maya, we can then impose any position-running or climbing-on the model, and the textures will look photographic," says Jerry Brown, texture artist.

When the model was completed, it was passed to lead animator Steve Cady, who, along with Thomson, gave Sheena her extraordinary physical abilities. In one instance, the digital Sheena was to run up a tree, jump, swing to another tree, then run across rows of treetops. To get the timing right, Cady studied film footage of Nolin running and jumping. "Sheena moves differently from humans-she has an animal-like gait," says Cady. "So in addition to reviewing tapes of humans climbing ropes, for instance, we also looked at footage of various animal movements, like monkeys climbing trees.
The digital Sheena's movements are a hybrid between human and animal motion, which reflects the heritage of the fictional character on the show.




"There's a scene where Sheena is climbing a mountain and has to cling to rocks. But she couldn't look like a trained mountain climber, because as part of the show's lore, she learned how to climb from animals," Thomson explains. "We had to make the action look different from human movement, yet it had to be believable."

According to David, another challenge was ensuring that the digital movement blended well with the live action in both the preceding and following scenes. To accomplish this, animator Jamie DeRuyter received a photographic plate with the filmed background images and the camera movements, into which the character model was to be composited. He then set up a camera in Maya that simulated the set lighting and camera motion as closely as possible. This was done by going onto the set and measuring the lens angle, focal distances, camera height, and so on.

"The animators use that camera to animate the character, so when the model is rendered and composited back into the photographic plate, it looks natural in the shot," says David.

Besides creating a character double, the animators also used computer graphics to replicate live-action scenery and backgrounds. According to compositor Amber Larkin, individuals from Victory FX and Corsica review the film footage for each episode, from which they break out all the shots needing effects and morphs. To simulate a realistic jungle environment, the artists gather reference material depicting images from African jungles, then use Paint Effects and Photoshop to create dirt, bushes, branches, trees, and leaves. For compositing the CGI into the live action, Larkin uses Avid's Illusion. "Using CG effects has enabled us to do a lot of things in the show that just would never have been possible any other way," says Corsica's Sears. "This is especially true for the environments, which look like they are shot in Africa."

The degree to which the 3D set elements are used varies-from an all-CG background to one that includes a few digital objects-depending on what's needed in a scene. Using 3D elements in the background is occurring more frequently, according to DeRuyter. "We have found that more often than not, with Maya Paint Effects, we can get a better look than by using stock footage for our heavy CG shots," says artist Phil DeLaCruz. "We can also keep the interactivity in the 3D environment because it moves with our 3D cameras and is affected by other geometry and forces generated in the computer."

In another episode, the group modeled and animated a Jeep falling from a ravine. "There aren't many cliffs in Florida, so the producers had a difficult time coming up with the shot," explains David. "At one point, they attempted to use a miniature vehicle against a bluescreen. But we looked at it and agreed that we could do a much better job." After downloading a Viewpoint model of the Jeep, the animators "adapted" it to what was used in the live action by applying textures they had shot of an actual vehicle. Next, they modeled the cliff and landscape around it. "We delivered a seven-shot scene that's totally digital to the production group. We even inserted a photographic image of the driver into the CG model in the first shot."
To create an African jungle in Florida, artists used Paint Effects and Photoshop to turn a flat area (top) into a gorge (middle). The finished shot (bottom) shows live actors composited into the scene.




Larkin also performs the numerous morphs for Sheena shape-shifting into an animal. After receiving film footage of Nolin and separate footage of the animal, she removes the animal trainer from the shot, then creates the in-between images in 2D using Avid's Elastic Reality. "Right now they're filming live animals, but we had a general question from the producers concerning what it would take to create digital animals once the morph occurs in the scene," Larkin notes. "We're intrigued by the possibility of modeling a dangerous animal and having it look convincing, which I think is in our future."

According to Boris Malden, producer/production manager at Corsica, each episode must be completed in six days, which could not be done without using computer graphics effects. "I can also tell you that the show would be nowhere as exciting as it is now without these effects," he says.

Adds Sears: "The show would be impossible without CGI-you'd have talking heads and very little, very rudimentary action and no morphing. Even if we had a $2 million budget, we couldn't accomplish everything we do now. Though we're limited by time and budget in what we can do, we're not limited in creativity."

Karen Moltenbrey is a senior associate editor for Computer Graphics World.

Adobe Systems * www.adobe.com
Alias|Wavefront * www.aliaswavefront.com
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