'Fred Claus': Putting Christmas in Jeopardy With VFX

When holiday season comes, Santa Claus is always a crowd pleaser in multiplexes, and every time, visual effects seem to reach new levels of realism when bringing his enchanted world to life. This is definitely the case with Fred Claus, a David Dobkin movie opening Nov. 9 from Warner Bros. Pictures. This comedy tells the story of Fred Claus, a bitter man who happens to be the exact opposite of his brother Santa. When Fred is obliged to enter the family business, his actions end up putting Christmas in jeopardy...

To coordinate the visual effects effort, Warner Bros. enlisted Visual Effects Supervisor Alex Bicknell and VFX Producer Arthur Windus. The movie was originally budgeted at around 450 vfx shots. After the first assembly, the shot count swelled to 1,200 before settling down to around 650 by the final cut. Seven vendors contributed to the project: The Moving Picture Co. (236 shots), Cinesite (150), Peerless Camera (110), Rainmaker UK (45), Richard Bain (50), Base Black (35) and Machine (25).

When CGI Goes North

As with most Santa Claus movies, the visual approach required a delicate balance between realism and fantasy. "David wanted the look of the effects to fit into the overall design of the film, which was fantastical yet set in the real world," Bicknell recounts. "This was particularly relevant with the North Pole, which had to appear like a real place that existed somewhere in the Arctic, yet was warm, inviting and magical. The main challenges turned out to be the creation of the North Pole, its population of elves and the sleigh rides. The North Pole was a huge CG build, and getting the look that the director wanted, both day and night, took an enormous amount of time and effort."

That effort was undertaken by Visual Effects Supervisor Uel Hormann and his team at MPC, including VFX Producers Merrin Jensen and Sally Spencer, CG Supervisor Matt Hicks and 2D Supervisor Mark Curtis. The general look of the city was first developed by Production Designer Allan Cameron, and then further augmented by MPC's Art Director Nelson Lowry. Once the designs had been approved, modelers used Maya to build a toolkit of houses based on a LIDAR scan of the practical set. These were textured using photographs taken from the same set to create 18 houses and five large town hall/church buildings, which were then placed into the approved street layout. The huge workshop was modeled, and textures were created using the on-set photography and a lot of reference shot in London. The highly complex building turned out to a bigger and more complicated piece than the whole of the rest of the 7,000-building city!

The key challenge was then to make sure that all the textures and shaders worked at night, at sunrise and in cloudy and sunlit daytime lighting environments... To address the tricky lighting issue, MPC used a custom lighting interface for Maya that essentially replaced all the lights, slim and MTOR. This simplified and standardized many of the render passes, allowing the lighter and compositor to have a lot of control on the final image without having to resort to a re-render in RenderMan when lighting changes were needed.

A Company of Elves

Once the city and its environment had been completed, the team needed to populate it with hundreds of diminutive elves. The production was lucky enough to come across a Russian circus troupe called the Lilliputians, all of whom were little people with a great range of circus skills, an ideal combination to portray the elves. Although there were 32 in the troupe, they were multiplied on screen using motion control repeat passes (with costume changes for variety). To increase diversity, the team also shot 75 full sized extras on blue screen stages. They were then reduced and composited in the scenes.

Due to many dynamic camera moves, the sequences often required the creation of CG elves to fill in the backgrounds. Inevitably, some of these digital characters ended up being almost full screen height in a handful of shots. MPC started with a cyberscan of 10 of the little people. Three different LOD (level of detail) models were made. The highest resolution was used to a maximum of 1/3 screen height, then two resolutions for the midground and background elves. Whenever an elf had to appear at full screen height, extra detail was added in the specific areas required.

"Each elf was built so that it could have its jacket on or off, wear ice skates or shoes and wear one of three pairs of glasses or not," Hormann notes. "To expedite the processing of the motion capture data, we came up with a way of using our proprietary crowd tools to target all the data to a single skeleton, and have the software and rigs work together so the animation could be used on the other nine elves. Textures all came from photographs taken of the various costumes and props. To help make 10 elves into 1,000 without getting too many repeats, texturing made many variations to the design of the waistcoats and shirts for the male and female elves. Shading then added another layer of variation by making the shader randomly select a color for the jacket, trousers and hat of each elf from a swatch sampled from all the fabrics of the live action costumes. For the actions, we established with Alex Bicknell a list of what we needed to capture, built the props required, and spent time at Audio Motion in Oxford capturing each scene.

"There was only one shot that used the crowd software in the traditional, simulation way; all the other shots used the captured clips that were positioned and timed using our proprietary crowd engine ALICE in non-simulation mode. This flexibility over simulation packages like Massive made it possible to treat each shot as if it was a hand-animated piece, whilst still managing to get first passes on shots with 1,000 elves in a matter of days. Then, clothing animation was simulated in Syflex. We rendered the shots using sub-surface scattering for our foreground and midground elves. Final composites were assembled in Shake."

For lead elf Willy, another approach was required. The character provided the team with an interesting challenge as 6'1" actor John Michael Higgins had been cast as 4' Willy. Having recently supervised 1,000 head replacement shots on a little person for Little Man, Bicknell certainly had some experience in the field. "Due to the comedic script and frequent improvisation, David wanted Willy to be able to interact directly with Fred in situ, which excluded the use of split screen techniques for the majority of the shots," Bicknell recalls. "Armed with my experience on Little Man, I suggested going down the head replacement route. We first played all the scenes with a little person named Jorgé standing in for Willy and miming his body to match John Michael's dialog. Then, we waited for a first cut of the scenes, and embarked on four weeks of secondary photography against a bluescreen. We lined-up JM with the Jorgé plates, and set up eye-line markers to represent any characters or relevant objects that were represented on the 'A' plate. JM was seated on a swivel chair that allowed him to rotate his body to match any perspective moves that Jorgé's body made -- any travel through the set would be created as part of the digital composite. Whenever the camera move on the A plate affected a change of perspective, I mimicked it by eye using a dolly on the blue screen set." More than half of the head replacement composites were created by Peerless Camera under the supervision of VFX Supervisor John Paul Docherty. These involved very complex paint work, motion matching and CG clothing/skin replacement, completed by a five artist "high speed compositing" unit centered on Autodesk Inferno systems. The rest was shared out among other facilities, including MPC, where half of the head replacements for Little Man had been completed.

Making Santa Fly

The final challenge of the movie was one that plagues most Christmas movies featuring the iconographic Santa and his unique method of transport; namely, the sleigh and flying reindeers. Early in pre-production, the team decided on a practical sleigh and real reindeers for scenes featuring the static sleigh. The two sleigh ride sequences were made up from a combination of the sleigh mounted on a mechanized gimbal shot against a bluescreen, and a fully CG incarnation, including the passengers, sleigh and reindeer. The backgrounds were sourced from helicopter footage shot on location in Chicago, stock footage sourced from round the globe, 2D matte paintings and fully CG environments.

"David wanted to make the rides straddle the real and fantastical worlds," Bicknell says. "To explain how Santa could deliver the presents in one night, we developed a kind of warp speed that required moving the sleigh so fast through the environments that it ends up being just a streak in the sky. I initially found the visual hard to grasp as the sleigh was so un-aerodynamic and the wind interaction on the characters a relative breeze compared to the 1,000 miles plus an hour speeds. Eventually, the juxtaposition of these two elements created a sort of cocoon inside the sleigh that actually helped sell the concept that they were traveling in our world, but somehow within the fabric of it."

Cinesite created most of the sleigh ride scenes, with in-house Visual Effects Supervisor Simon Stanley-Clamp overseeing the effort with VFX Producers Angie Wills and Catherine Duncan. "The extreme speed of the sleigh implied that a lot of physical ground was being covered," Stanley-Clamp notes. "3D Supervisor Jon Neill, with Zoran Arizanovic, constructed a huge 3D environment in Houdini for the underlying cityscapes. For the cloud work, we modeled a series of organic cloud shapes in Houdini. From this, we set up an automated grid, which could cover an area from as little as a foreground element to a vast panorama.

We were able to paint clouds and gaps where we wanted. Then, from the resultant geometry, points were derived from the surface and from the interior of the shapes using our proprietary software to create a volumetric point cloud. Then, again, using in-house tools, a sprite was assigned to each point. We attached a shader that had subsurface scatter and lighting direction attributes, which was rendered out as RGBA passes for integration and regarding in compositing. All this enabled us to create huge layers of 3D clouds to pass through at high speed and place them to match the angle and direction of the gimbal sleigh. For wider shots featuring the actors and practical sleigh, a 3D track was generated from the live-action plate and our reindeers added into the shot. This involved attaching the hitching gear of our CG to the practical sleigh at the linkage, and hand animating our CG reins from the reindeers to line up with the actors' hands."

During principal photography, each live reindeer was shot and extensively photographed under flat controlled lighting conditions to provide the backbone for the fur textures and details of the antlers. Modeler Erik Ellefsen took precise measurements and notes before embarking on the 3D model build in Maya. Meanwhile, Head of Animation Quentin Miles filmed the reindeers to capture reference for walk, trot and run cycles, jumps, leaps, etc. A lot of thought went into the design of the hitching gear, the mechanism by which reindeers are attached to a sleigh for the actual pulling.

"David Dobkin's main concern was that the sleigh in flight should not look like it was on a roller coaster -- i.e., too controlled and predetermined," Stanley-Clamp observes. "Peter Clayton and Jason Ivimey blocked out initial animation flight paths, building in secondary animation once trajectories were signed off -- to "rough up" the flight paths for air pockets, etc. Peter also modified the sleigh animation rig so that the leaf springs of the sleigh runners would squash-and- squeeze and move independently from the main body of the sleigh. It was subtle, but added a lot to the landing shots." The shots were then composited with Shake or Inferno.

The Delivery Ride When the initial ride becomes actual gift delivery, Rainmaker UK was called in to create the shots. VFX Supervisor Adam Gascoyne oversaw the project, with VFX Producer Laurel Schneider and Head of CG Sean Lewkiw. The team used a wide variety of packages, including Houdini, Maya, LightWave, modo and ZBrush for modeling, Houdini for volume lighting, RenderMan, Mantra and LightWave for rendering, and Photoshop, Shake and Stitcher for compositing.

The Delivery montage was shot entirely on bluescreen and no background plates were shot. "We were given creative carte blanche to create a montage of background for the sequence, which suggested that Fred was traveling all around the world," Gascoyne explains. "We spent two weeks acquiring a library of stills and moving footage and stitching it all together, adding steam, snow elements and Christmas lights as we went. It turned out to be quite a task to add Christmas decorations and a winter look to the backgrounds as the stills had been shot in August... For the Paris sequence, we built a very detailed model of the Eiffel Tower, which required a massive effort amount of hand modeling. We also built a basic model of Paris in LightWave, referencing aerial photos from Google Earth. This allowed us to get the correct scale for the area. We then went to Paris and shot thousands of high-resolution photographs to use both as projections and reference. These included 360-degree panoramas of the city taken every half-hour from the tower, which gave us flexibility with sky textures and light conditions."

Fighting Suspension of Disbelief

It only takes one night for Santa to deliver his presents to children all over the world, but it took more than a year-and-a-half for Bicknell and his team to visualize it. "Christmas movies that feature Santa, elves, flying reindeers, etc., are difficult beasts as they are fantastical to start with, and therefore, the audience's suspension of disbelief is challenged from the get go. However, I feel that David and Allan Cameron created a world that was so warm and cheerful that we had the template to extend it beyond the cast and sound stages. I feel that all the visual effects worked in tandem with the look and experience of the movie, and really helped make it one of the biggest live-action Christmas movies every made."

Alain Bielik is the founder and editor of renowned effects magazine S.F.X, published in France since 1991. He also contributes to various French publications, both print and online, and occasionally to Cinefex. In 2004, he organized a major special effects exhibition at the Musee International de la Miniature in Lyon, France.