Canine Companionship

Buck the dog is always CG in the film. Images ©2019 Twentieth Century Fox Film Corp.

Jack London's "Call of the Wild" is a classic read for many middle schoolers. It is a story of adventure and hardship in the wilds of the Canadian Yukon during the Gold Rush of the 1890s. It is also a tale of survival and eventual friendship between man and dog. In this story, "man" is John Thornton (played by Harrison Ford), who rescues the canine from a harsh master. "Dog" is Buck (a photorealistic CG creation), a large but gentle St. Bernard/Scotch Collie mix that is snatched from his happy domestic life and forced to become a sled dog in the northern wilderness before he finds happiness once again with John. Until he hears the wild beckoning to him.

Based on the American classic novel, Call of the Wild is from 20 ^th Century Fox. It is directed by Chris Sanders, with Erik Nash (Iron Man 3) as visual effects supervisor and Ryan Stafford as visual effects producer. MPC Montreal handled the CGI, including the star, Buck.

Adapting the story from book to film was an adventure in itself. Consider a large part of the cast: Buck and the other dogs on the sled team, as well the wild animals including a grizzly bear, a herd of caribou, rabbits, birds, and a wolf pack, among others. All are photoreal and crafted in CGI by Moving Picture Company. And they are always CGI in the film. Then there were the extensive outdoor environments. Certain sets were constructed for the film, but many others were built or extended in CGI, too.  In all, the film contains approximately 1,250 visual effects shots, most of which are animation shots.

Initially, filmmakers considered making the film mostly CGI-driven but opted for the hybrid approach, incorporating more photography with the computer-generated animals. Still, Nash estimates that as much as a third of the film is computer-generated.

Here, Buck as well as the background are computer-generated.

Casting Buck

Buck carries the emotional arc of the entire movie. And from the amazing work, it is nearly impossible to tell that the dog is not real. To keep him planted in reality, the dog does not speak. And he is never anthropomorphic.

"Buck is the star of the movie, and the audience has to connect with him and feel his emotions and understand what's going through his head. And I believe Buck delivered in that regard," says Nash.

The reason for always using a CG dog was twofold, according to Nash. It gave the filmmakers full control over Buck's performance throughout the film, especially since there was a lot of acting required of him. The animals, particularly Buck, needed to be fun and playful, as well as empathetic and emotional - and at times extend beyond the limitations of real-world animals.

"We wanted to have the flexibility and freedom to art direct Buck because he was our star," he says.

Also, the filmmakers wanted to have full control over Buck's look, down to the finest detail, and not be bound by matching a real--life dog to the description from the book.

According to Giles Davies, MPC Film Character Lab asset supervisor, Buck underwent two design phases, with two distinct directions for his look. The initial intention was that Buck's look would be based on key art from the studio, with supporting references of a practical dog close in breed and built to the art. No actual dog was cast as the CG dog, he emphasizes, resulting in a process of translating and validating the 2D key art references in 3D. "At this time, Buck was intended to be black and white, and more closely resembling a Bernese mountain dog," Davies adds.

However, while shooting night scenes, the filmmakers realized that having a dog with so much black fur was less than ideal, so they went back to the drawing board - or more accurately, to the kennel. Scrolling through an animal rescue website, Sanders' wife found a St. Bernard/Farm Collie that would be a good companion to their aging dog, Brody. She then drove from LA to Kansas and adopted the dog, whose name, ironically, was Buckley.

Buckley was light brown in color, which worked better in terms of the lighting and visibility in the night scenes. So Buckley then became the new model on which Buck was loosely based. The artists received new scans and photography to inform the new direction, adapting the existing model, including a complete re-texture and groom. While Buckley proved to be a good reference model, he was not a trained movie dog and thus was unable to be used as a stand-in for lighting reference. (Buckley, did, however, get to walk the red carpet with his new owners at the movie's premiere.)

The 3D artists then used variations of the digital asset as Buck's physical condition - more/less body mass, coat condition - changes from sequence to sequence based on the story line.

"Unlike the other 12 or 13 dogs in the movie, Buck was the only one we 'designed,'" Nash says. Those other canine characters were based on real dogs that the filmmakers had cast - not for their performance, but rather for their appearances, which were replicated in 3D.

A Model Dog

MPC is well known in the industry for creating photorealistic animals of all kinds (see "Lions and Tigers and Bears, Oh My!" page 18), and has an equally impressive reference library in terms of the material breadth, including a wide range of animal behaviors and actions to reference.

To build Buck, MPC artists used Pixologic's ZBrush and Autodesk's Maya: ZBrush to translate the key art to 3D, and Maya for topology UVs and so forth. A combination of Maya and ZBrush was used for the facial shapes.

For the fur, MPC used the latest incarnation of its in-house grooming tool, Furtility. To get an idea of how much fur was involved, Buck has about seven million hairs, and a percentage of those were used by the tech-anim department for simulation.

Indeed, Buck's fur was a big undertaking, particularly since he is put through so many situations and conditions. He gets wet, he gets muddy, he rolls around in the snow. And all those scenarios were reflected in the condition of his fur. The same goes for the other dogs. To this end, Buck had several groom variations - for instance, "healthy," "on the trail," "icy,' "wet," "soaking." Tech--anim was able to use those varying looks and even mix between them, depending on the needs of the sequences, says Davies.

Another challenge for the artists was creating the dog's facial features, which had to hold up in a number of close-up shots, especially those that were tight on the character's eyes. "We were always reflecting the environment in the surface of the eye, or an actor if Buck was face-to-face with someone," says Nash. "The asset and lighting teams did some incredible work with the eyes."

In essence, the artists received an in-depth biology lesson, as a veterinarian surgeon provided the group with information about the physiology of the eye and how the various surfaces react to light, as well as how skin color and age inform the eye color and retina reflections. "As a result, we remodeled the geometry of the eye and updated the textures and shading," Davies explains. The group took their investigation even further, arranging for a dissection session with video and photography capture to reinforce the asset team's understanding of eyes in general - knowledge they were able to transfer to the task at hand when modeling the character.

In Motion

Nash emphasizes that no motion capture was used to animate Buck or the other animals; they were 100 percent keyframed. However, in some instances, Buck's performance was informed by Terry Notary (Planet of the Apes), particularly for instances during principal photography in which Buck is interacting with and around humans. Nevertheless, there was always an animator interpreting Notary's performance and then using that as inspiration for the keyframed performance in the film.

"As talented as Notary is, it's important to note how Buck's performance came about - it's really the artistry of Omar Morsy [MPC Film animation director] and his team at MPC in Montreal, because they really were the artists who created Buck's performance," says Nash.

As Nash explains, Notary did not wear a head camera rig, nor did he have facial markers, as dogs and humans have totally different facial structures, thus negating any procedural one-to-one transposition of facial performance. That said, Sanders would direct Notary on set to get a desired performance. That performance served two purposes: It gave the human actors something to react to and play against, and it provided a broad foundation for the animation teams in terms of general attitude.

"We often used Terry's acting performance and even our own animators' performances to get all the acting across," says Morsy. "We wanted to make sure that everyone from a child to an adult could pick up on all of Buck's most subtle thoughts and feelings."

Yet, Buck's facial movements are subtle, and thus, more natural. "The tricky part was finding that fine line where we could get across what Buck was thinking or feeling, yet have it remain within a real-world range of expression that the audience would accept as being something a dog could, and would, actually do," says Nash.

Because the animators had to hit all the nuances of Buck's acting as well as physical actions, they used references of real dogs of the same size and weight as Buck for all the body mechanics and locomotion. So the animators built a quadruped rig that would enable them to properly hit four main points.

First, there was an IK and FK controller on the head. "Most of the time we used FK to get proper curves from spine to head; however, on a few key shots where Buck would have to hold onto something with his teeth or if he wanted to caress someone with his cheek, we would need an IK system to get the desired result," Morsy explains.

Second, they needed a proper controller on the spine that allowed them to adjust the silhouette. While not a proper spine controller, it enabled the animators to sculpt the dog's torso and give them the shapes they needed.

Third, a robust foot roll system was required that gave the artists multiple pivot points around the paws for the many different ways Buck would use his paws.

Lastly, the group needed a thorough FACS-based facial system that helped them remain true to real dog facial expressions and gave them full control over Buck's face using both real muscles and points of control that would help show excess skin folding while being manipulated from outside forces. "For example, if a dog opens his jaw to eat something, you would see a level of crinkle on his snout as he lifts his lips to bite it. However, if he is just holding on to a bone, the lips would be up without the crinkle, so we needed to be able to do both," explains Morsy. "That, along with a gravity tool that was hand adjusted and also had an auto setting to compute velocity and weight in the face, gave us a version that was then sent to our tech-anim department where they adjusted and sculpted the finishing touches that gave us the final result we see today."

Despite these advances, finding a balance between realism and performance was hardly a simple task. "We all know that dogs can emote and that the range of emotion a real dog can show is quite vast; however, there are just some feelings and thoughts that are far too subtle, if there at all, in a real dog," Morsy points out. "So to aid us, we used Terry Notary and our own acting to tell every little beat of the story. The objective was that everyone would understand all the emotional nuances of Buck and his growth throughout the movie, turning every audience member watching the movie into a dog whisperer."

Northern Exposure

Nash estimates that about 60 percent of the film is plate-based photography, and the rest is CGI. Principal photography took place in Southern California - during the summer. And other than the opening of the movie, the vast majority of the film is set in the Yukon, mostly during the winter. So, it was up to MPC to build this setting of mountains and forests and so forth, with all manner of snow cover that comprised FX and VFX. Indeed, there are some practical sets, such as a partial physical build of the mining town; but, it was then significantly extended digitally. However, when Buck is in the wilderness and not around humans, everything in the scene is CGI, including the environments.

"Those portions of the film were produced using a virtual production paradigm - akin to that used for The Lion King." says Nash. One critical scene called for a very specific type of high-energy camera work - the nighttime fight between Buck and Spitz, the lead sled dog. "We wanted a really dynamic and reactive camera. So for that sequence, we did rough animation in Montreal, transmitted the files to the Fox Lab in downtown LA, and used their virtual camera system to 'shoot' the scene." Using the Lab allowed Sanders to be present and to direct the shoot interactively.

The remainder of the all-CG scenes utilized MPC Montreal's in-house virtual camera system. This live camera allowed the team of artists to impart the CG camera work with very much the same character as Janusz Kaminiski's live-action cinematography. "Avoiding the traditional keyframe approach for creating camera moves, and instead using virtual camera tools, gave us a consistent camera language across the real and digital," Nash notes.

Whether it was a CG or plate-based environment, the lighting pipeline relied on global illumination - whether from high-dynamic range photography taken on set or using the digital environment and the lighting condition selected for it. Nash credits Richard Clegg, in-house VFX supervisor, and his lighting team for always having Buck seated nicely within the environment, right out of the first comp.

Buck’s facial movements are natural and subtle, adding to his believability.

Animal Actors

"Call of the Wild is a story about an innocent, pampered pup who is forced to grow and evolve through all the dangerous realities of this world, slowing transforming him into a mature, hardened, almost feral animal. And just like the human actors in this movie, Buck had to hit all the acting notes required to tell his story. This depth of acting would have been impossible with a real dog," says Davies.

Moreover, Buck had to physically transform in the film, as he faced those harsh conditions. Not to mention, all the physical action that would have been potentially harmful to an actual dog. So, for this film, there was no choice, really, in whether to cast a real dog or a CG one.

Of course, there are always humane concerns when live animals are used in film production. But with the proven technology today, photorealistic animals of all kinds are answering the casting call - not just as background characters, but also as leads.

"I think what Call of the Wild does, among other things, is open filmmakers' eyes to the possibilities they're now afforded by advances in technology, where things you couldn't do in the past with digital animals are now possible," says Nash. "Up to this point, digital animals for the most part were either animals that talked or animals that weren't truly realistic. Clearly, with that a possibility now, albeit not an inexpensive one, productions have the opportunity and responsibility to assess on a project-by-project basis, whether to use live animals or go the CG route."

And as the artists and animators have proven with the exceptional work on this film, such a call is now easy to make.