G-Force: The Men Behind The Guinea Pigs
Disney Enterprises, Inc.
A young boy told his father that he thought his classroom’s pet guinea pig had a secret life as a special agent. His father, visual effects master Hoyt Yeatman, became inspired by the concept and fleshed out a story. He told a friend about this creation. The friend, master producer Jerry Bruckheimer, saw the potential for a clever action film, and “G-Force” was born.
What came next was the development of teams whose unified mission was to breathe life into the guinea pigs of "G-Force." Animation Supervisor Troy Saliba and Visual Effects Supervisor Scott Stokdyk began working on the concepts immediately.
”My role starts when a client comes to me with some designs showing what they want," said Saliba. "Hoyt was very specific about the film’s visual style. He wanted to create a hybrid of live action and animation, and he wanted photo-realistic guinea pigs."
Saliba’s first step was to realize the designs digitally. Knowing that the guinea pigs were also special agents performing tasks that defy their anatomy, Saliba and his team made slight anatomical readjustments to provide greater flexibility for the guinea pigs.
"The production office had about six different guinea pigs, and we’d constantly be referring to them," said Stokdyk. "They also had what we called a skinny pig, which is basically a hairless guinea pig. Because so much of a guinea pig is the fur, the hairless guinea pig showed us a lot of the anatomy and what’s going on at the base skin level."
While developing the animated characters, Saliba and his team also prepped the actors for their vocal roles. They provide rudimentary animated scenes so the actors could become familiar with how their voices matched the guinea pigs.
"This helps the vocal talent come on board and get used to what they should focus on," said Saliba. "It also helps the production executives see the direction we’re moving towards."
While the animators developed the skeletal rigging and basic geometry of the movement and background, the visual effects team was building additional layers upon the animation. Using programs like Maya, Arnold, Houdini and Renderman, the textural reality of the movement and lighting of the many layers of fur on the guinea pigs was developed.
"We were always trying to make sure that the lighting touches and integration work and effects work all pulled together to be convincing, and provide you with a very realistic looking experience," said Stokdyk.
In order to accurately integrate the guinea pigs into the live action setting, Stokdyk and Saliba closely followed the work of production designer Deborah Evans and director of photography Bojan Bazelli.
"The production designer comes up with the foundations of the environments," said Saliba. "We take those designs, and say, ‘O.K., what do we need to be doing in this scene?’ We used proprietary tools to survey the data and measure the distance between the camera and the object so we could match them perfectly. "
Adds Stokdyk, "As basic environments got set up on stage and filmed, we were constantly referring back to that plate photography. We used Hoyt’s HTR camera, which is a system that captures High Dynamic Range footage that enables us to record light positions and intensity. Back at Imageworks, we extract all that data and put it into our lighting pipeline."
Close attention had to be paid to scale and vantage point when blending the live action footage with the scenes taking place from the guinea pig level.
"The film is a hybrid; it’s part live, part digital. The great scope of the movie is viewed from eight inches off the ground," said Saliba. "But, you’re also seeing a view of the world from Mooch, a house fly. And, there’s also an 85 foot tall robot, so you have to blend the scope of all these perspectives." Adds Stokydk, "That robot is animated, it’s a creature, and it’s also an environment. For the G-Force to get in there and interact with it, we had to come down to their scale. Everything’s constantly moving and that becomes a whole virtual environment. We enhanced it with atmospheric smoke and sparks and effects elements to really create that world."
Although many of the environments were completely fabricated, there were others that blend live action and the animated critters. For a scene that takes place in a pet shop, a sophisticated camera set-up allowed the CG characters to interact directly with a photo plate background.
"A tessilator was used," said Saliba. "The camera is mounted on a stand that rotated around a three dimensional dome where the live action footage was shown. The animation becomes perfectly tailored to the camera work." "It’s kind of the opposite of a movie like ‘300’ were there’s a blue screen foreground and a CG background,” added Stokydk. "Here it’s a CG foreground and a live action background."
While the movie blends animation, visual effects and live action, Rob Engle and his 3D visual effects team elevate the film one more step, taking the film and applying a stereoscopic 3D process.
"Troy breaths life into the characters, Scott oversees the plate technology, negatives and designs. My team takes the aspects they were working on in 2D, and turns them into a 3D film," said Engle. "In the 3D version of a film, every shot is a visual effect. Every shot has to be treated."
"We tend to look at what is closest to us," explained Engle. "It’s about the instincts of personal space. The 3D story is a new way to connect with the audience. In 2D you are very aware that you are watching a movie. With 3D, you feel like you are part of the action. You feel like you are in the guinea pigs world, down on their level."
In a stereoscopic film, there are essentially two movies. The 3D VFX supervisor has to ensure that the left and right eyes are seeing the subtle perspective differences in each film. Although there is a process where film can be shot simultaneously on two cameras, Engle and his crew manipulated the 2D frames to create the stereoscopic effect, eliminating the double camera setup and creating a separate 3D film from the 2D master.
"On ‘Beowulf’ we developed tools that allowed viewing of the virtual world in 3D. From there we create depth parameters," said Engle. "The chief challenge is to take the plate technology from the traditional film, create the 3D effect and integrate our guinea pig costars back in. It’s adding an extra step."
Even though Engle was converting the film to 3D, both Saliba and Stokdyk’s teams had to make conscious choices in how they developed the animated and CG scenes.
"Working in 3D, you have different staging considerations that you need to keep in mind,” said Saliba. “They are subtle things. Breaking the framework, timing considerations, over the shoulder shots. The composition principles remain the same, but the 3D changes the depths of field, and gives you another world to be concerned with."
"We had more freedom and less restrictions than on a typical stereoscopic movie," said Stokdyk. "We were able to work with a limited set of restrictions on the normal movie and pass things over to Rob, and he would occasionally tell us things that might work better in 3D. We extended some shots to be a little longer and slower so they wouldn’t be jarring in 3D. And, we paid extra special attention to our effects elements: sparks, fire, bubbles. There are a lot of subtle adjustments in a 3D movie that I don’t think affect the overall story telling, but affect the visual storytelling. It becomes more about being immersed in the environment"
The 3D element allowed Saliba and Stokdyk to become really creative with the animation effects with scenes such as an underwater mission the G-Force engage in.
“First and foremost, it was an animation challenge to get a nice, smooth underwater feel to the elements in relation to the camera, the camera movements, and the many layers of depth that would read well once we went to a stereoscopic release, “ said Stokdyk. “We wanted to do some very specific things with the guinea pigs in relation to the water, the camera, and the sense of light, so we created those shots synthetically; referencing underwater footage we shot on set. We created a lot of tiny particulate matter floating through the water that would help us read the camera moves. We also did a lot of bubble work, where the bubbles were catching highlights and giving depth and dimension.”
In addition to applying the 3D VFX to the movie, Yeatman wanted to take it one step further. He requested that the 3D elements break through the masking, allowing the viewer to get a sense of how far objects were extending beyond the confines of the scene.
“The biggest challenge of using this technique was in deciding exactly which objects should break the frame,” said Engle. “Often, when taking one element over the mask, a snowball effect would occur. We’d find it desirable to add more and more layers usually because the compositing logic or depth layout of the shot dictated it. In the end, we found that the technique was most effective when used sparingly.”
On his first venture as a director, Yeatman was excited to break standard film conventions, but never strayed far from the concerns of his animators. Having worked on effects movies ranging from “The Fly,” “Mighty Joe Young” and “The Abyss” and receiving a special Technical Achievement Oscar in 2000 for his advancements in matte compositing photography, Yeatman worked closely with the animation and VFX teams to ensure their jobs ran smoothly.
“Hoyt is a giant in the industry, and it was exciting to have him at the helm,” said Saliba. “He always gave plenty of of set-up time for the visual effects and never rushed us when the crew had to wait for marks. Hoyt really looked out for us, knowing what it’s like working with animation and CG.”
“He was constantly working with the grips and the camera crews to come up with really innovative ways to get background plates and photography that was really amazing,” said Stokdyk. “From the very start, we shared a visual mind set about what the movie was going to be about and how it was going to look.”
“Troy and I always thought the cool thing about his movie was that if you really believe that there can be these cute little furry guinea pigs that could be your pet and then you see them in the context of doing extraordinary things, that’s what’s going to be fun,” said Stokdyk. “That’s what’s going to give this movie an edge.”