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A More Scientific 'Day the Earth Stood Still'

Jeff Okun tells VFXWorld how a modern technological approach informed the retelling of The Day the Earth Stood Still.


In this remake of The Day the Earth Stood Still signature effects such as the spaceship from outer space, Gort the robot and Klaatu’s eerie sphere were updated. Photo credit: Weta. All images ™ & © 2008 Twentieth Century Fox Film Corp. 

Since its release in 1951, Robert Wise's The Day the Earth Stood Still has remained one of the most admired science-fiction movies of all time. So it wasn't an easy task for director Scott Derrickson (The Exorcism of Emily Rose) and his team to revisit this classic story for modern audiences. It was even more so for Overall Visual Effects Supervisor Jeff Okun, who had to revamp such signature effects as the spaceship from outer space, and Gort the robot. The Twentieth Century Fox remake (which opened Friday) re-imagines the original storyline in which an extra-terrestrial named Klaatu arrives on Earth aboard a giant and eerie sphere. The character has come to deliver a message, but with 21st century, environmental twist...

When Okun started work on the project, the initial vfx shot count estimation was 750. It then went down to 480 shots by the time the team was ready to shoot -- a result of resource streamlining and various in-camera approaches agreed upon. In post-production, the final shot count rose to 507, as all parties agreed that a few more tweaks were needed to help tell the story with more impact. Surprisingly for a project of this complexity, there were very few "fix-it-in-post" additional shots.

The team had the opportunity to benefit from a generous six-month preparation time. "The film looks as good as it does because we had that time to prep, explore and test in pre-production, and were able to stick with our plan during production," Okun insists. "Post lasted about five months -- including element shoots, shooting new sequences (which Jim Rygiel, a friend of mine, supervised while I was in New Zealand) and the like.

"We used 10 vendors on this show. Weta was our primary vendor, accomplishing 221 shots of stunning reality and beauty, and incredibly adhering to the budget and the schedule. Cinesite ended up with 42 really dynamic shots of the Drone attack, the interrogation sequence, as well as the opening shot and a few snow matte paintings. Flash Film Works did 95 shots featuring some great CG helicopters, driving comps, matte paintings and rain additions. CosFX created 74 shots mostly dealing with rising spheres, still life in New York City and many composites. Hydraulx did 13 shots of the amazing looking attack on the missile silo, while Hammerhead did three very difficult shots dealing with a helicopter landing, and a still life interior and the Trooper healing shot. Screaming Monkey created 3D birds for the "Super Sphere" shot that Weta did. We also used Digital Dimension and Digital Domain, as well as nTropic, for several matte paintings, life coming to a stop and the like."

A New Approach

Early on, the team decided to update the technical approach of the original movie and take it to the next generation of vfx. That meant no man-in-a-suit for Gort, and no practical model for the spaceship. "We wanted to make sure that the visual effects would not upstage the story and we wanted to honor the spirit of the original film," Okun notes. "So, we took the point of view that we should try and make everything feel as if it were happening right now, as if it were real. And not 'movie real', but 'real life' real."

This approach led to a specific path of research: What would an alien race do to deliver their message to Earth in a manner that we, the apparent primitives by comparison, would understand and not be afraid of? Possible answers to this question were tossed around in numerous round table discussions. Team members would suggest ideas based on movies, books, articles, documentaries, images and on discussions with scientists from various fields. Nanoparticles were discussed, SETI was interviewed, Microsoft contributed concepts and prototypes.

This data was then processed to elaborate a kind of physics that could be applied to the action and intentions of the aliens in the movie. Some of the questions that had to be answered were: would a superior alien race really physically travel in spaceships? What would the alien choose to look like? Would they come out looking scary or friendly? How would they deliver their message? And finally, how would they destroy the species that was doomed and how would they save the other ones? The process of looking for the answers turned out to be extremely useful to design the film's imagery.

Anything but a Sphere

The basic concept of the spaceship had already been established by the time Okun joined the project. "I have had to deal with a sphere before, most notably for Barry Levinson's Sphere (1998), and learned a lot about them. There are so many issues with this form. They look the same from every angle; they have no scale; they reflect things in a very unexpected manner; and no one I have ever met has had a real life experience dealing with a sphere that was larger than nine feet. Our sphere was 300 feet tall! This turned out to be a huge problem."

One of the issues was that, since a sphere is perfectly round, almost its entire diameter is in the air. "Let me clarify: since our sphere is sitting 15 feet in the ground, the curve extends out from the center of the sphere almost 135 feet in every direction! That's quite an overhang! Due to the curve, you would have to be a mere five or seven feet from where it touches the ground to be able to touch it… Now, if that sphere had just landed, would you really walk underneath such an overhang? So, this had great impact on where the action of the scene was played, and had other physical impacts as well -- like, does the alien walk down a ramp? How far out does the ramp extend? How close would anyone really be to the thing? So there I was, stuck with another sphere… "

Okun tried to talk Derrickson out of the sphere concept, but the director had an organic vision. His notion was to have a sphere that looked like a small gas planet, without any hard surface anywhere: Quite a unique concept. "I really mulled all of the images and discussion over and realized that the sphere could be a portal instead of a spaceship, meaning that I was not locked into anything to do with spaceships. It became the touchstone for all sorts of exciting ideas. In the end, who knows if anyone gets our concept, but in reality, wouldn't it be easier to send a portal across the universe and then just step off your planet through it and onto your destination? This kind of future science really was needed so I could understand what we were making and why. Also, it really helped the artists at Weta get the feel of what we were going for. That was all fed, combined with the artwork, into the brains of the Weta artists and the sphere is what came out. Magnificent, amazing and very difficult to replicate! One time, it would come out perfect, and then the next time, it would look completely different. Many a sphere was rejected with the words 'Not Our Sphere,' which soon became 'N.O.S.'!"

Spheres posed many challenges: They look the same from every angle, they have no scale and they reflect unexpectedly. This sphere was 300 feet tall with almost its entire diameter extending in the 135 feet in every direction.

At Weta Digital, Senior Visual Effects Supervisor Kevin Rafferty and Visual Effects Supervisor R. Christopher White assembled a task force that included Digital FX Supervisor Matt Aitken, 2D Supervisors Areito Echevarria and Phillip Leonhardt and CG Supervisors Mike Perry, Mark Tait and Allen Hemberger. They used a variety of tools, including Maya for modeling, rigging, animation and lighting, and RenderMan for rendering. Compositing was a combination of Shake and Nuke, with Nuke playing a leading role in the creation of virtual environments.

After extensive look development on the sphere, Weta's team decided to proceed with physically-based, ray-marching RenderMan shaders that could shade a virtual volume, with density and lighting calculations derived from the properties of real gases. The sphere was basically created by taking extremely high resolution animated texture maps based on manipulated satellite imagery of weather systems, and extruding them into a spherical 3D volume. Several varying layers of this were combined with animated lights that moved in and out at of the depths of the sphere in order to create mysterious inner glows. Further treatment at the compositing stage involved sweetening these various elements and adding rays and other atmospheric effects to integrate them into their environments. Fractals were used to modulate the texture in order to provide more detail in the cloud structure, whenever the sphere was featured close to camera.

Okun was particularly impressed with a hero shot that Weta delivered: "Kevin Rafferty, compositor Cameron Smith and host of their colleagues made a fabulous shot out of the spheres in what we called our 'Super Sphere' shot: five spheres seamlessly hooked together in a single shot that travels from the swamp to Central Park to the desert to the jungle to the ocean. Amazing work!"

Re-inventing Gort

Parallel to the sphere design effort, the production team and Weta were even harder at work on Gort, the robot. While the spheres were a tough concept to visualize, Gort was the design challenge of the movie. Everybody was aware of the fact that it was an iconic character. Once again, when Okun started the project, Gort was all ready well under way. He was originally conceived as an alien creature that walked on four legs and then folded up into a kind of totem pole or idol. Quite a "re-invention" of the original beloved monolithic design…

Weta wrote custom software to simulate the swarm. One of the more unique features, was the way groups of elements would target things to

Okun acknowledges that he had been a huge fan of Gort ever since he was a kid. And that he was not really happy with the direction the character was taking. "One day, the round table team was reviewing some recent updates to this alien creature design. I finally admitted out loud to the group that this creature, while very cool, was not Gort; that the little featureless man in the corner of the drawing was more Gort to me than this… There was a very long silence in the room. Then, producer Erwin Stoff said, 'I feel the same way…' And then, one by one, everyone admitted that they too felt that way. So, we just rolled up our sleeves and started over!"

Several groups contributed designs for Gort, including Spectral Motion, Weta Digital, Cinesite and The Aaron Sims Co. "We finally arrived at a very good Gort, and Weta made him three-dimensional," Okun confirms. "But the resulting model did not look as good as we had hoped. So, we went in and refined him to take advantage of the way light reflects off him. In the end, Gort is entirely computer-generated."

At Weta, Animation Supervisor Eric Reynolds oversaw the character animation effort. The team combined traditional keyframe animation with motion capture of a live performer, similar to the way Kong was acted in King Kong. Lighting Gort made extensive use of calculating spherical harmonics to achieve a high degree of photorealism. "Spherical harmonics" is a technique for efficiently calculating the shading and shadowing of 3D objects. It takes into account the entire environment the object is in, and how that environment affects the lighting of the object.

A massive and seemingly unstoppable alien force destroys a stadium in seconds. Destructions were simulated with various in-house tools created for use within Maya, and rendered using RenderMan.

The most dramatic difference with the original Gort is the weapon that the robot uses to make a point. The 1951 Gort fired laser beams that quickly became a signature effects for all sci-fi movies that followed. In the new version, his weapon of choice is a destructive swarm that eats away anything in its path.

Swarm Behavior

Weta examined a few approaches to simulating the swarm before making the decision to write custom software for it. The new tool was based on several papers describing the distinctive motion of large flocks of birds or schools of fish. Each element had an awareness of its surrounding neighbors and some simple instructions to tell it what to do at a given moment in time: "approach this goal," "avoid obstacles," "stay near your neighbor," "try to stay aligned with them," etc.

One of the more unique features of the software was the way groups of elements would target things to "eat." A group of elements would attack an object based on its size, and, as it was eaten, it would naturally grow smaller, which would cause elements to flee and target other larger objects. This caused some remarkable cascading effects as sub-swarms would move from object to object, attacking and destroying it and moving on. Destructions were simulated with various in-house tools created for use within Maya, and rendered using RenderMan. Rendering the swarm itself required some further software development to allow rendering more than a billion particles in some instances, and to provide controls for subtle iridescent color-shifting that accentuated the darting motion inherent in large flocks.

Not surprisingly, The Day the Earth Stood Still turned out to be, by far, the most difficult project Okun have ever worked on. For that reason alone, it was also the most satisfying. "The obstacles that we faced in honoring the original while updating it for today's -- and hopefully tomorrow's -- audiences were enormous. But the work will speak for itself. All we hope for is that we provided a compelling story, told in an interesting way, that pulled the audience members in, entertained and even informed them. The visual effects work is the best I have ever done, and I owe that to the talented artists who worked with me at the various facilities involved. They should really get the credit for not only bringing my vision and that of the director's to the screen, but also for going the extra mile to give us more than we hoped for."

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.