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Furious FX Races to 'Witch Mountain'

Burbank-based Furious FX took on their largest project to date with Disney's re-imagined Race to Witch Mountain, creating UFOs, SUV collisions and eerie blue alien lights along the way.

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Furious FX took on their largest project to date with Race to Witch Mountain, with an eventual shot count of 860. All images © 2008 Disney Enterprises Inc. All rights reserved. 

In 1975, Walt Disney Studios used clever in-camera tricks, wire effects and optical composites to achieve the magic of Escape to Witch Mountain, a family film in which two teenage extraterrestrials desperately try to go back to their spaceship. The movie was so popular that it spawned two sequels and a remake. So it comes as no surprise that Disney has rebooted the franchise with Race to Witch Mountain, taking full advantage of CG.

That task was awarded to Furious FX -- it was to become the largest project ever undertaken by the Burbank-based company. "This project was greenlit at 353 shots, with a majority of the visual effects elements shot on second unit," Executive Visual Effects Supervisor David Lingenfelser says. "During filming, we all had a sense of it growing, mainly due to the amount of camera coverage, and so many successful takes between the stunt and action sequences. Once the first edit was assembled, and everyone loved the excitement level in these scenes, we found ourselves nearing 960 shots, though these eventually tightened to around 860."

Lingenfelser adds that the biggest challenge was adapting to the growth of the project, and ramping up their smaller facility with the highly skilled artists, hardware and software needed to create all of the vfx. "We had prepared for the initial shot count, though my business partner/Executive Producer Scott Dougherty and I soon found ourselves posting job listings, then setting up phone interviews and negotiations while working on location! In the end, we had six months of post-production, which was a good amount of time, though quite solidly packed and fast-paced for our 40-person crew. In addition to the work itself, we also had to accommodate a variety of studio needs such as temp versions for trailers, marketing presentations, and audience preview screenings. These are all key ingredients for a successful film release, and we have grown accustomed to allowing for these deliveries in our schedule."

Overall VFX Producer David Yrisarri brought Proof on the lot during pre-production to previse the three major sequences that had the most complex effects. These approved animatics provided the reference for the plates that were shot on location. "We are fans of capturing everything that can be got in camera, as is [director] Andy Fickman," Lingenfelser notes. "When the need arises to look beyond live-action solutions, that's when we discuss how a CG approach can help. In the past, we have worked on movies where there seemed to be a desire to use CG for no particular reason, though it is always better to complement with a digital approach due to limitations of the set, location, actor safety, time constraints, etc. The two work much better hand-in-hand."

Frontal Impact

Furious FX faced one of its more challenging shots with what later became the most memorable image from the film's marketing campaign: a slow motion shot where alien teen Seth (played by Alexander Ludwig) takes on the full impact of a speeding SUV. "The success of that image depended greatly on the photorealism of the vehicle and its animation. In addition, the actor was shot fairly close-up using a wrap-around camera move, and the decision was later made to slow the action down to a crawl at the moment of impact... So, there was no relying on a quick cut or motion blur to make things easier. Every piece of debris required the same level of detail, right down to the last lug nut!"

This particular shot, and the rest of the project, was entirely created on Mac platforms. The primary 2D pipeline consisted of Nuke for compositing and Silhouette for rotoscoping. 3D work was based on Maya and mental ray, with some tasks being completed in LightWave.

The first step was the creation of a 3D mesh of the SUV, which utilized the on-set cyber-scanning services provided by Eyetronics. The practical SUV was photographed using a high-resolution camera and two flash units. One of these was used to project a grid on top of the SUV from multiple angles, while the other captured texture information. The data was then used to generate a highly detailed and accurate computer-based model of the vehicle.

"The next step involved setup and rigging of the model to allow for animation," explains CG Supervisor Mark Shoaf. "A combination of high resolution blend shapes and IK rigging was used in order to properly affect the SUV in relation to its collision with Seth. The entire crash was then hand animated by a character artist utilizing this setup. This approach turned out to be more efficient and less problematic than trying to simulate the collision using rigid body dynamics. The final step was setting up the full-detail render. High resolution texture maps were painted and applied to the individual surfaces of the SUV, an HDRI environment was built using photos taken on location, and the final images were then rendered using mental ray."

A sequence where the alien kids escape in a spaceship used a CG ship, based on the original 1970s craft, with a digitally-created tunnel.

UFO Chase

Similar digital SUVs and military vehicles were created and animated for the later scene in which our heroes escape by flying their spaceship through a tunnel, hitting walls and oncoming vehicles in the process. The spaceship was designed by director Andy Fickman and production designer David Bomba. Their intent was to create a somewhat nostalgic ship that felt reminiscent of those in the original films.

Production built a practical spaceship set that served as a basis for the digital ship. "We started with some initial measurements along with many photographs of the practical spaceship," says Shoaf. "These were used to model the craft as a polygonal mesh using Maya software, to which texture UVs were then applied, along with additional high resolution textures we painted for the ship surfaces. Based on continuity, the intention was to match the practical ship already captured on set, though we were able to experiment with a CG electrical vortex as its energy source. Everyone was so pleased with the blue plasma nature of this effect that it was requested in many other sequences whenever there was a need to convey alien energy."

Since there was no actual set reference built, the tunnel itself was created from scratch in CG using Maya software. "The design cues for the tunnel came from both the practical underground hangar set, and additional research based on military installations such as NORAD," Shoaf continues. "The various surfaces and elements of the tunnel were modeled first, then appropriate textures of metals, cement, and rock were created and applied. Secondary properties such as ceiling cloth simulations, swinging overhead lights and blowing dust were later added to show reaction to the spaceship as it travels through. The animation of the ship was initially blocked during previsualization, so we used this as our guide, then refined it with secondary animation as well. The cars, military vehicles, and collisions were all animated by hand."

Most of the vehicles were either built from scratch in Maya or were taken from the facility's model library. They were then re-worked and textured to meet the specific needs of the sequences. Other vehicles, such as helicopters and the hero taxi cab, were cyber-scanned using the same process as with the crashing SUV. All the hard surfaces of vehicles were set up and generated using the mental ray renderer. The renders were broken down into various layers such as diffuse, specular, reflection and ambient occlusion in order to help with more flexible integration once handed over to compositing.

Furious created the shots in about six months, with a 40-person crew.

Mars Room

Even more fantastical was the "planetarium" scene in which the alien kids utilize a giant three-dimensional spatial navigation system. "An earlier concept for the so-called Mars Room was more of a hologram projected from a map", Lingenfelser recalls. "Once we were brought on board, and Andy saw the Hall of Snow Globes we had created for The Santa Clause 3, this idea began to evolve. Andy really loved how all the snow globes floated around the actors, creating multiple layers to capture the eye. So, we worked from that basic idea and transformed it into our solar system. We added in a wide assortment of deep space elements from the alien kids' travels, and wound up with a hybrid of images both familiar and never before seen. While we were on set during principal photography, the 3D artists at our office were already busy designing and building these new planets. Andy really let us run wild with the elements in this scene, which resulted in such an exciting visual landscape through which the actors could walk around."

All of the planets in the Mars Room were created in Maya as full 3D elements. "Planets range from hard surface models, combinations of lighting effects, to full fluid dynamic simulations," Shoaf explains. "Based on individual shots, varying levels of detail could be adjusted for each planet to reflect its proximity to camera. One major challenge of this sequence was in maintaining continuity with so many angle changes and extensive dialogue. Whenever the edit would change, with shots added, cut, lengthened, or trimmed, the potential need for reworking several surrounding shots would arise. The majority of the scene's elements were rendered using mental ray, though the Maya renderer was also used in some cases."

Rising to the Challenge

Needless to say, realizing more than 800 shots in six months time with such a small crew was quite a challenge for Furious FX. But the work proved so successful that all the major effects shots were heavily featured in the film's marketing campaign. "We couldn't be happier with everything we've accomplished over the past year," Lingenfelser concludes. "Our crew has been truly amazing, as we were fortunate to find such a talented group of artists and production personnel whose skill and commitment made such a large-scale project possible at a smaller facility like ours."

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 Musée International de la Miniature in Lyon, France.

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