BackDrop July06
Interview by Chief editor Karen Moltenbrey
Issue: Volume: 29 Issue: 7 (July 2006)

BackDrop July06

Fur Fun
Rhythm & Hues places an improved CG Garfield into ‘hairy’ situations in the fat cat’s live-action sequel
Rhythm & Hues has a long history of character animation, going back to the early ’90s with the Coca-Cola Polar Bears. In 1995, with the Academy Award for Achievement in Visual Effects awarded to R&H VFX supervisor and co-founder Charles Gibson for Babe, the studio established itself as the leader in the talking-animal niche, with Stuart Little (cats), followed by Cats & Dogs (felines and canines). Rhythm & Hues leveraged the talking-animal reputation with its strong character animation pipeline, and started doing fully CG-animated characters for live-action films and commercials. Some of those included Mr. Tinkles in Cats & Dogs, Scooby-Doo (1 and 2), Cat in the Hat (fish), and the first Garfield release in 2004. That run culminated with the recent box-office smash and Academy Award nominee The Chronicles of Narnia: The Lion, the Witch and the Wardrobe, which featured the photoreal CG Aslan lion and 40 mythical character types, under the supervision of one of R&H’s in-house VFX supes, Bill Westenhofer.    

Betsy Paterson
is Rhythm & Hues’ VFX supervisor for Garfield: A Tale of Two Kitties, overseeing a crew of 300 digital artists to bring the feline back to the big screen. Her supervisor credits include The Ring 2, both Scooby-Doo films, and others.

What was the extent of the work you did for Garfield 2?
Rhythm & Hues’ scope of work for Garfield 2 consisted of 390 shots featuring a 3D animated Garfield and/or his alter ego, Prince. We created, animated, lit, and composited Garfield and Prince, his almost identical counterpart, and all the things that they interact with.
During how long of a period?
We had about four months of development and about six months to do the actual shots.
How many people worked on it?
At our peak, we had more than 250 people on our crew from the US and India.
Did other studios work on the film?
Rainmaker in Vancouver also did a significant amount of work, particularly the ‘talking animal’ portion. They are liveaction animals with CG faces.
You also did the hair and compositing for the original Garfield movie?
Yes. We did the animation, as well, for the film.
How did the work this time differ?
Garfield got an upgrade to take advantage of advances in our software and pipeline. He also got some slight modeling tweaks. He’s actually fatter this time around. Our animation rigging has improved, so it was a bit easier to get more iterations of animation, and to get more believable fat, skeleton, and muscle interaction. As with any film that depicts an animated character, that character is an actor; it must evoke emotion and be totally believable. To that end, we made improvements to the original Garfield rig so that he moved more naturally than in the first movie.
Did you create any new hair and fur technologies or techniques for the film?
We’re constantly tweaking our software, so in a sense, we create new technology on every job. Most of the recent advances have to do with better application of environmental lighting to the fur itself, better sheen, and better self-shadowing.
Would you describe your fur process?
The fur is groomed and controlled using various levels of guide hairs. Maps are used for color and opacity. Several different lighting layers are rendered so that details like sheen and shadows can be controlled in the composite.
Which tools did you use for the hair/fur?
We use our own proprietary software for just about everything we do. Our main package is called Voodoo.
Did any of this technology evolve from the work you did in Narnia?
Absolutely. Every show is built on the things we learned from previous shows.  
Compared to the other cat you crafted recently, Aslan, how does Garfield’s fur differ?
Garfield’s fur is longer and messier. It’s probably more like Aslan’s mane than his body fur.
How many hairs does Garfield have?
There are 3.3 million hairs on him. The pelt hairs were grown off of Garfield’s polygon surface using hand-painted pelt maps that determined the length, density, clump, scruff, etc. The guide hairs were also created using the same techniques, but they controlled the direction, flatness, scruff, and other parameters to give the overall flow and directionality to the fur.
How did you animate the hairs?
The hairs are not animated by hand except in special cases. Most of the time they move according to physical rules, similar to a particle system. When other objects touch Garfield, the guide hairs are animated to move the fur appropriately.
What about the lighting?
The fur is lit the same way any other CG object would be lit, using a combination of environmental lighting obtained from HDRI taken on the set and hero CG lights. The orange color is very sensitive to different colored lights, so we generally toned down the contribution of the environmental lighting. Every shot needed individual attention to maintain the balance between realistic lighting and keeping the orange color as bright and saturated as the director wanted.
What did you use for rendering?
We render using our in-house renderer, Wren. The improved light/comp pipeline enabled us to make adjustments to color and lighting without having to go through a time-consuming rerender each time. In addition, we created 2D motion blur that significantly reduced rendering time. In the past, motion blur would have been applied prior to rendering, but using 2D motion blur allowed the crew to apply it in the comp stage.
What was the biggest fur challenge?
We had a number of shots where substances had to get stuck in the fur. CG lasagna sauce in one scene, and mud and dirt in another, all had to stick to and fall out of the fur.
How did you accomplish that?
First, special grooming and textures were created that made the fur look wet and dirty. Then, individually modeled pieces of mud or sauce were attached to the hairs. These were also controlled with a rules-based system that allowed them to interact with the fur, and react to gravity and fall out where necessary.
Did the fact that you had two cats in the film this time impact your process and rendering times?
Not really, except that the shots in which they were together took twice as long to render. Now, onto the compositing.
How did you naturally blend a CG cartoon character into the live action and make it look rather seamless, as if the characters belonged?
The HDRI and other data that we collect on set is very important for making sure that the lighting blends seamlessly. Once the character is rendered, quite a bit of work goes into the integration. Contrast levels, color, and film grain need to match the plate. Contact shadows and reflections are rendered and need to be composited convincingly. Pieces of the plate are roto’d and comped back on top of the character.
What were the biggest challenges you faced in putting the CG characters into the live action?
Both cats spend quite a bit of time on soft surfaces, like beds and couches. They needed to be able to push into these surfaces so that we believe that they have real weight. Getting the shadows right in these situations is tough. We also had several shots where people pick up and carry Garfield. These are always challenging and require quite a bit of frame-by-frame work for both the trackers and the compositors. To do this work, they used our in-house compositing software called Icy.
Is there anything else you want to point out about the work in this film?
The best part about working on sequels is that you’re getting a second chance. The work we did on the first Garfield was fantastic, but there are always things you would do differently if you had it to do over. A sequel gives you that chance. All the work—animation, lighting, compositing—was some of the best CG character work we’ve done…’til the next one, of course!