Computer Graphics World

October 2008 18 n n n n CG I artists. e animators got involved. We did 60 percent of the film in this high-school play type of video. In the first movie, we locked off the camera to reduce rendering time. It felt a lot like postcard shots. With this one, we had more processors." And that gave the directors more flexibility. For example, when they were planning the plane-crash sequence, the directors turned a couch in the art department on its back, put a lion's mane wig on an artist playing Alex, and had Mireille Soria, the producer, play Gloria. McGrath took the role of Melman. As Navarro filmed, the crew acted out the scene. e footage he shot then moved to an editor, who cut the video into a story reel. "Normally, we'd use storyboards and then do a first pass in 3D," Meyer says. "It would take a week. But with live ac- tion, it takes a couple of hours. And like live action, we got a lot of coverage. Unlike traditional animation, where we'd have a story and an alternate, we had eight, 12, 15 takes. Reverse, side, wide angle. e edi- tor would ask, 'Did you shoot a close-up of Marty?' We'd have close, tight, wide, fast, and a high angle." Some of the shots in the final film look like a camera operator filmed them with a handheld camera. Others have smoother camera moves. "e first time we see the watering hole, the camera starts over the shoulder," Meyer says. "en we boom up to see the huge landscape. Later, when Alex finds his par- ents, we have a tight, long lens and a static camera. But, when the animals are escap- ing from the tourists, the camera is hand- held. I think the cinematography pushes the envelope for 3D animation." Fields of Grass Also pushing the envelope in this film are the effects. In Madagascar, the effects crew concentrated on the jungle and on giving natural phenomena cartoony twists by cre- ating curlicue clouds and funny dust that spiraled into artful shapes. Madagascar 2's spacious landscapes focused the effects ef- fort in broader directions. "e first film was all about the jungle and how hard that was," Gluckman says. "Little did we know the savannah would be harder. Now when we have a jungle shot, the lighters breathe a sigh of relief." For the dense jungle in Madagascar, the effects crew baked background trees onto cards, a technique that didn't work for the grass in Madagascar 2's vast savannah. "e grass was extremely painful," Gluckman says. "ere was no silver bullet." To create the grass, the effects crew devel- oped a new set-dressing tool that gave the layout and surfacing artists an efficient way to plant the grass on a 3D ground plane. "Lay- out artists have a library of curves that they select, place into a scene, and loft to create patches," Peterson explains. "en, they pass those curves to the surfacing department." Artists in the surfacing department place geo- metric stand-ins that look like little boxes of various sizes and heights on the curves. e stand-ins conform to the undulating ground and extend far into the distance. e new tool then converts the little boxes into dis- placement maps that the effects artists plug into the fur shader. And, the fur shader fills the boxes with grass. "e fur shader talks to a shader in- stancer," Peterson explains, "and instances geometry along the curves." e shader also randomly adds accents, such as seed- pods and flowers created in the modeling department. When characters walk through the grass, the grass bends and moves aside because of a tool called Smoosh, written to manage the interaction between Puss In Boots' fur and his costume in Shrek the ird (see "Merry Tales," April 2007) and updated for Mada- gascar 2. e tool uses collision detection to determine how the grass should move; that is, in which direction, how much, how fast, and whether it oscillates. "We also kick in wind from the characters," Peterson says. "We have simple animations that provide the collision response based on the length of the grass." As the grass recedes into the distance, the blades become wider and farther apart to shorten rendering time. To render the fields, the crew used a technique by the studio's researchers, Feng Xie, Eric Tabel- lion, and Andrew Pearce, titled "Soft Shad- ows by Ray Tracing Multilayer Transparent Shadow Maps" that they published for the Eurographics Symposium on Rendering (2007). As the title implies, the technique uses transparency to achieve anti-aliasing for the grass blades and eliminate buzz- ing. By using shadow maps, the technique keeps the rendering cost lower than with stochastic raytracing. To fill the big skies over the capacious The wild African animals in Madagascar 2 have more rounded shapes than their zooster cousins. Animators at PDI/DreamWorks could pluck any character from a crowd and treat it like a hero.

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