It is, without a doubt, the most intense and spectacular sequence in Super 8: As kids film a zombie movie at a train station late at night, an Air Force train whips by. Suddenly, a pickup turns onto the tracks, derailing the train, raining fiery metal debris over the countryside and releasing something decidedly not of this world into a small Ohio town.
Though the film opened Friday, the creation of the stunning sequence started more than a year ago. Director J.J. Abrams and Paramount, the studio behind Super 8, wanted to run a teaser trailer before Iron Man 2, so they asked visual effects house Industrial Light and Magic (ILM) to create the teaser. "From initial conception to final delivery was done in four weeks," Kim Libreri, one of the visual effects supervisors on Super 8, says. "We had two weeks of preproduction, and in the middle we shot the live action pickup truck element. Then we had two weeks left to deliver."
VFX artists began by looking at photos of real-life Air Force trains from the late 1970s and using that reference to construct digital carriages in the computer. While there wasn't much video reference for trains actually crashing and derailing, there was plenty of train-crash aftermath, Libreri says. "You get that classic zigzag of the carriages. So we looked at that, and we looked at physical collisions of large-scale objects to see how they would interact with the ground. YouTube was an amazing source for us."
When the digital train was ready, animators ran it through disaster simulations—inputting how much each car weighed, its dimensions, and the speed it was traveling to see how the cars would fly apart in a real-life collision. "But even if you get something that looks absolutely real, it isn't necessarily what the audience expects to happen," Libreri says. "So there is still a fair amount of animators putting their artistry into the final results. You start with a simulation and then dress it up with keyframe [hand] animation on the top to make it more spectacular." That includes adjusting trajectory so a car flies at the camera, having a bouncing carriage kick up extra debris, or even spraying fuel in a certain direction for more impressive explosions.
Once the teaser went out the door, it was time to think about the sequence that would appear in the movie. Though approximately 80 percent of what was created for the teaser trailer made it into the final movie, filmmakers needed much more to complete the scene. Abrams knew exactly what he didn't want: gratuitous visual-effects shots. "He wanted to ground it with the kids' performance, so the audience really feels the danger that is happening to the kids," Libreri says. "A lot of movies nowadays take you to this God's-eyes view, where you get to see everything happening. And he didn't really want to do that. There were some storyboards that J.J. did, but it was a very organic process, covering the action beats. We did use some green screen, but most of it was shot wild."
At the Firestone Ranch near Los Angeles, the production team laid turf to simulate the green grasses of Ohio and built a train station and tracks. Filming was done in two stages: First, Abrams filmed the kids on the train platform with green screen behind them; visual effects artists would later replace that screen with a train whizzing by and extend the train tracks beyond what was laid out in real life.
When that was complete, it was time to stage the train crash. To destroy the station—in which a train car runs through in the film—the special effects department built a green sled on rails, rigged it with explosives and smashed it into the building. Abrams set up nine cameras around the station to film its destruction from as many angles as possible. "That was a fantastic explosion," Libreri says. "It looked great."
For the next sequence, in which the kids run through the wreckage as the train continues to derail, the production team littered the area with a dozen cut-up old carriages. Abrams again shot with multiple cameras—three this time—to follow the kids through the wreckage. "We would have explosions going off in the background, and we would shoot the cameras with relatively long lenses, which compressed the distance between the kids and the explosions—so it felt like the explosions were really close to the kids," Libreri says. "It was never dangerous, because it was a fair distance, but the kids were basically reacting to big explosions going off."
There was even some VFX ad-libbing based on the kids' reactions. "If the kids flinched, you would want to put an extra carriage flying past in the background to tie into their reactions," Libreri says. "That was the biggest challenge—making it feel like the train crash and the kids' journey through it is one thing. I think it works. You feel like these kids are running for their lives."