Bringing Sony Pictures Animation's first computer-generated movie "Open Season" to life in "Warner Bros. style" wasn't easy, said Animation Mentor artist Chris Williams. It meant making characters like the domesticated grizzly bear Boog, the mule-deer Elliot and the rabbits move, squat and stretch in cartoon-ish "Warner Bros. style."

One of the more challenging shots for Williams focused on a scene where Elliot stands outside Boog's home and throws rabbits, instead of rocks to get his attention, at the bear's bedroom window. The rabbits needed to squash up against the glass, rather than break it.

Williams said anchor points in the animation software let him flatten and reshape the rabbits to make them look believable. Sony plans to release the animated feature, also in 3D, in September.

"Boog was fun to create because we got to play around with his volume and control surfaces to exaggerate his features," Williams said, who also is a lead animator on Spider-Man 3. "I worked on all three Spider-Man movies doing realisms, and the CG-movie was a nice break to tackle other challenges."

Animators who have worked on major comic adaptations like "Spider-Man 3," "Superman Returns," "Hellboy" and "Blade" were on hand Thursday at Comic-Con International 2006 in San Diego. They participated in a panel discussion of their work, and they spoke of the challenges of bringing comics to movie screens.

For "Spider-Man 3," scheduled for release next year, software developers at Sony Pictures Imageworks Inc., Sony's visual and special effects house, created a software tool to calculate the effects that physics has on an object to make the scene more believable.

Software developers scripted software code into the visual effects tool Autodesk Maya that animators use. The "physics tool" calculates the effects of gravity on objects. It takes velocity into account, measuring the size of the object and speed required to leave the ground. Then it calculates the trajectory required based on physics and what that parabolic curve would look like, said Andy Jones, animation director at Sony Pictures Imageworks.

"In a movie like 'Spider-Man' there's a lot of jumping and swinging, things that happen in the real world, but it is movie physics, and in some cases it's very different than real-world physics," Jones said. "If Spider-Man had to jump from here to there, the physics tool would give us an idea on how the curve would look in real world gravity. We use that as a guide."