John Carter and the Creatures of Mars

The artists created nearly all the movie’s creatures plus a selection of environments, all of which needed to coordinate with the work of Cinesite, the facility responsible for the majority of the project’s CG sets, and the live action. The Utah desert, wide open, barren country under dazzling bright sunlight, was the shoot location chosen to represent the Martian landscape.

The team’s detailed on-set data capture would not only be required for accurate tracking and placement of their creatures into the live action. They were also asked to create some of the especially creature-heavy environments in the film - the White Ape arena, internal views of the Thark’s city and exteriors for the Temple of Iss.

Finished Image
“We also worked very closely with DP Dan Mindel on the whole show. We would talk at length about lighting and atmosphere so we could extract the most information from each set-up during the shoot. We were always conscious of the finished image allowing space and composition so that when all the elements had been added it still retained his photographic style.”

In the pipeline, Maya was used as the foundation for all modelling, and for rigging and animating the creatures, with numerous proprietary plug-ins and pipeline tools built around it. All the costume and fur dynamics were handled through a combination of Maya and Houdini.

Martian Tribe
“Andrew Stanton always described the Tharks as a nomadic, Masai warrior type tribe, but with the raw aggressive nature of Vikings,” said Peter Chiang. “The dry, arid, sun-bleached atmosphere affected their look. We made several refinements to the design once we started, based on look development and animation studies. Andrew wanted them to feel more human to help translate the actors’ performances captured on set. He also wanted to direct the performance closely, so we developed a facial capture system and also made minor alterations to the eyes and muscle structure. The eyes originally had black sclera but we made them white like humans’ eyes for a better expressive read.”

Although similar to people, the Tharks are very tall, have two sets of arms, no nose and external bones curving around their faces. Nevertheless, they were always regarded as characters that needed to deliver a specific performance. The animation team, led by Steve and his co-animation supervisor Eamonn Butler, worked hard with Andrew to convey this feeling. Early studies established a lot of the character traits and this led the requirements for the look development.

Skin Deep
Once animation tests began, the Tharks’ key muscle groups were brought back closer to the moves of their human counterparts for the natural mechanics to work convincingly. It was important for the principle Thark characters to stand out from the crowds of other Tharks. All the females had face paint and wider hips, for example, and older Tharks tended to be more blue-green, but a tonal approach was always used to create more depth in the skin. The heroes’ costumes received more work, but any Thark moving close to camera needed high detail.

Eye to Eye
Tracking and compositing the CG Tharks into the shots and making them look convincing standing next to the real actors was one of the biggest challenges in the film. Most of the tracking was handled using Double Negative's proprietary PhotoFit software, and all compositing in Nuke. “We always started with the actors who played the part of the Tharks in shot, rehearsing the action until Andrew was happy,” Peter said. “We tried to use the take with Carter, without the Thark actors, as the chosen plate so we could minimise clean up. This meant adding all the shadows and light interaction back onto Carter once we had an approved animation.

“The Thark actors were always shot with the correct eye line either on stilts, on boxes or decking or walking around with a backpack with a Thark head at the correct height for the character. We also had to prevent the very tall Tharks from overwhelming the hero John Carter and reducing his impact in scenes. Fortunately, Andrew’s eye for composition and staging helped with effective layouts for the shots.”

Performance Ready
The body motion of the principal Tharks was primarily keyframe animated, with the facial performance consisting of a combination of motion capture with keyframe enhancement layered on top. Steve said, “Due to the sheer volume of animation cycles required, we relied more on motion capture to flesh out our crowd system. The capture was done both at Centroid on their optical system and by using an inertia Moven suit. The creatures Woola and the Thoats were keyframed. We explored using motion captured camel data as the base for the Thoats’ movement, but it turned out to be too erratic to cover all the necessary actions.

“Andrew was very clear from the get-go that the Tharks had to stand next to the live action actors and be inseparable in their level of realism - they had to be able to hold their own. He also wanted a very tangible connection between the digital and live action worlds, which is why he was keen to have the Thark actors on set, acting with the live action actors with their eyes at the same height as their digital replacements.”

The final, third layer covers all distant Tharks and involved the greatest numbers, under the banner of Crowd Simulation supervised by Eugénie von Tunzelmann, FX Supervisor and crowd specialist. “She and her team used the animation library to populate vast areas of the background via a proprietary particle instancing tool through Houdini,” Steve explained. “They could digitally airbrush an area with particles, replaced with animation at render time, and blended different pre-animated sections of motion together to maintain richness and complexity in the backgrounds.”

Facial Performance
Motion capture was also the basis of the facial animation in most shots, producing a very natural looking performance to build on. Eye motion was entirely keyframed, using either the Thark performers' footage or additional animator shot footage as reference. A lot of attention was paid to the eyes because they had to hold numerous subtle, complex emotions in some extreme close-ups. The animators could layer on top of raw motion capture to accentuate, clean up or rework a performance, as needed.

“In addition, the nostrils on the Tharks were actually on top of their heads, so we ensured that they performed in conjunction with the rest of the face to reflect what regular nostrils would do. It's a small detail that most people won't even notice, but it would take away from the performance if they weren't there. Finally, we layered facial skin simulations on top of everything to tie all the relative areas of the face together, and give the skin additional secondary jiggle that really paid off in those extreme close ups.”

New Creature FX Team
Because the Martian creatures are not hairy or furry, skin and muscle were important to get looking right. “The muscle system gave us the generic bulges in the right place but a further layer of displacements added the shape detail. Skin sliding, tendons, folding skin and bone pressure changing the skin colour were all part of the tool set developed for the film in ‘Creature FX’”, Peter said.

Creature FX at Double Negative is a relatively new discipline within the realm of creature work. It was developed during John Carter to bridge the gap between the mesh centric world of rigging, and lighting and rendering. Creature FX supervisor Richard Clark explained that traditionally, creature TDs and riggers focus on making the mesh represent as much of the anatomical detail as possible and can animate, deform and drive the mesh in many ways. “While this approach has benefits, the artists can never use a mesh matching the level of detail seen in a ZBrush sculpt,” he said.

Flexing Muscles
As the Tharks are lean and muscular, every muscle had to be animated to support the whole performance. This involved developing a new tool for Maya called dnBeouf that communicates with rigs and renders and provides an animation interface giving feedback in hardware. They dissected every ZBrush anatomy sculpt to provide ‘areas’ to drive on the displacement map.

dnBeouf also drove mesh deformations such as muscle flexing on the rig, tendon deformation, dynamic wrinkles, skin sliding and compression data for skin colour changes. Richard said, “This gave us near real-time feedback for key framing to the performance. The result was viewed in the render to asses it with impact of lighting. Once approved a mesh cache was delivered to the lighting team to render for the final.”

Steve agreed that he doesn’t have the most instantly appealing face. “We started out by making his movement pretty cartoony and extreme, but in one of the first sequences we animated we found that by having Woola do less and appear more vacant and attentive to Carter’s every move, he became far more lovable. The lead animator for Woola, Craig Bardsley, focused his team on reference of bull dogs, pugs and boxers for locomotion and character traits. They spent a lot of time exploring how a creature of 400lbs could move at speeds up to 200mph, yet stop on a dime. By displacing his weight in number of creative ways they managed to avoid letting him feel like a Tex Avery cartoon.

Desert Transport
The Tharks ride massive, eight-legged beasts over the vast distances across their desert environment, calling for such reference as elephants, rhinos, horses and even camels at one point, as mentioned earlier. The heavy design of the Thoats' eight legs and their close proximity presented the animators with some difficult pose massaging and the need to play with the timing of the motion to avoid heavy intersections, especially when galloping. Due to its incredible size, the tail of the Thoats was played as if it had strong cartilage running through it to support its weight, but with minimal flex.

Because no motion capture was recorded on set, the Tharks were actually more forgiving because we could adjust their motion more easily to fit them to the Thoats.

Ape Interaction
At a high point in the action, John Carter is thrown into an arena with one of Mars’ most vicious creatures, the gigantic White Apes. They also posed a keen challenge for the creature and animation teams. According to Steve Aplin, “The White Apes had to be insanely physical and interact seamlessly with the environment, John Carter and the chains he wielded.”

Andrew's concept department had already heavily designed the Apes before production began, which needed only slight alteration during the animation test phase to accommodate a more expressive range of motion. Their lead animator Ben Forster had his team looking at silverback gorillas in particular for natural motion to key from. As they were at least ten times bigger than the average real ape, additional weight passes were added and their ferocity was cranked up to the next level.

Steve said, “We struck a careful balance between the speed the Apes had to move about the arena and maintaining the sense of extreme weight. They are also blind and seek Carter out by their sense of smell, so this had to be worked into their performance as well, in a way that the viewer would immediately understand.”
Words: Adriene Hurst
Images: Courtesy of Walt Disney Studios