Computer Graphics World


Issue link:

Contents of this Issue


Page 35 of 51

n n n n CG Characters A nimal experts will tell you that, despite the age-old adage that cats and dogs do not get along, a positive relationship be- tween the two is indeed possible, depending on the animals’ personalities. Tat said, it’s clear why the sourpuss Kitty Ga- lore is at war with, well, just about everyone—dogs, humans, and even fellow felines—in the live-action feature film Cats & Dogs 2: Te Revenge of Kitty Galore. What’s this rogue agent’s beef? She lost her beautiful coat at the paws of a dog, and soon after became ridiculed by her cat comrades and kicked out of her human home. Kitty Galore struggles with her baldness, which is at the root of her vindictive behavior. It also was a challenge of sorts for the artists at Tippett Studio who created her as well as approximately 10 other CG animals for the film. Tese computer-generated characters act alongside humans and animal actors, some of which have digital face replacements. “We had all the Kitty Galore shots, and she was a main character for us in about 100 shots,” says Scott Liedtka, Tippett’s co-VFX supervisor on the film. Te Tippett group used the studio’s brand-new hair system, Furator, to create the computer-generated animals’ coats (see “Here Kitty, Kitty” in the Web Exclusives section on Tat even holds true for the “hairless” Kitty Galore, who does not have a thick pelt but is covered in a fine layer of peach fuzz. “We had a few big challenges [on the film], but the one that you see on the screen is Kitty Galore herself,” says Liedt- ka. “Trying to match a hairless Sphynx cat, with all those creepy wrinkles and no fur to hide her skin and muscles, was a big job. We tried many techniques and ended up mixing a few to get her to work [well].” Te tale of Kitty Galore’s accident is recalled in a flashback with just a couple of shots, so luckily Tippett didn’t have to create a fully furred Kitty, too. Nevertheless, she still has some longish hair strands on her face, ears, feet, and tail that was a bit thick in some areas, while over the rest of her body, she has a short coat of peach fuzz that made her skin look velvety. Te group initially tested a faux fur shader on her, but Liedtka did not believe it would have held up well in the close-ups. In the end, Kitty ended up with a couple million hairs. Hairy Situation Crafting realistic animal fur is quite challenging, but creating this so- called hairless cat was even more difficult. “Te wrinkles, muscles, and skin shading all had to be pretty sophisticated to be convincing,” says Liedtka. “As hard as fur is, it also can simplify things. As long as the fur looks good, the character looks good.” 34 October 2010 Creating furry CG animals can be tricky, but creating one that is hairless proved to be even more challenging, as the artists at Tippett discovered while creating the evil character Kitty Galore for Cats & Dogs 2. To make Kitty Galore look good required the team to improve on a number of techniques that Tippett had been developing over a number of shows: tangent space vector displacement, pose space data to drive the displacement shader, pose space corrective blendshapes, shallow and deep subsurface scattering using blocking objects for skin shading, and Tippett’s own “eyemagic” technique to help compositors fine-tune the eyes with more shadow and depth. “Te individual ideas that were de- veloped for Kitty Galore were not especially difficult, but the combina- tion of all the techniques ended up being a hard task to accomplish,” Liedtka says.

Articles in this issue

Links on this page

Archives of this issue

view archives of Computer Graphics World - OCTOBER 2010