Stunt buses, a bluescreen stage and more. An excerpt from befores & afters magazine.
The latest issue of the magazine covers the VFX of Paul Greengrass’ The Lost Bus, starring Matthew McConaughey. This excerpt is about how they filmed the bus scenes, which involved real stunt shooting out in New Mexico, and shooting on a bluescreen stage.
Exterior sequences of The Lost Bus were filmed (by DOP Pål Ulvik Rokseth) in Ruidoso, New Mexico, standing in for northern California. A real bus was captured driving along roads and tracks as much as possible. Sometimes a pod car setup was employed, with a driver situated on the roof or in front of the bus, to enable shots of McConaughey ‘driving’ the bus (a platform positioned on the front of the bus provided the camera operator a space to film from). An array car fitted with a bank of cameras, and a gray/chrome ball, atop its roof was used to capture environments. A survey team also acquired HDRIs of every location, building and vehicle.
The starting point was always practical, but the film did rely on a large range of digital imagery, including of the bus. “We would take the live-action stunt bus footage and sometimes we might replace the bus with bus animation to give it more interactive light from flames,” explains visual effects supervisor Charlie Noble. “For close-up shots, we kept as much as we could.”
While a significant portion of the film was shot on location in New Mexico, a range of bus shots was also captured on a sound stage utilizing a practical bus. Safety was one reason for this methodology, since so many children were passengers. One of the early considerations was to build an LED volume and display footage on the LED screens for playback, interactive lighting and in-camera VFX shots, to be run by ILM StageCraft.
“The volume approach was just something that did not suit Paul’s very documentary-style approach in the end,” declares visual effects producer Gavin Round. “His method was to rehearse everything all day and then shoot in a small window of time when it was golden hour. In the story, the sun is obscured by smoke which meant there would be no shadows or anything. The volume setting did not really lend itself to Paul’s method.”
“Still,” adds Noble, “we actually generated a lot of footage to go onto those screens. ILM produced a lot of really great material to go on the screens, but then when we came to production, Paul was really keen to go out onto the backlot with the cast and the kids in the bus and drive around and just play whole scenes out on the bus, in the real bus, driving around with as much smoke and flame effects and all the rest of it that we could muster. The thinking was that once we’d done that, we could then go onto the stage to pick up pieces that we hadn’t got that we needed a little bit more control over.”
The bus on the stage was positioned on a specially designed rig, orchestrated by special effects supervisor Brandon K. McLaughlin. “Per the script,” advises McLaughlin, “I felt a traditional six-axis gimbal was going to be excessive and also put the children ten feet in the air. Loading and offloading was going to be a big problem. So what I came up with was a hydraulic ram on each wheel of the bus. We were able to raise and lower each corner of the bus a foot. It also allowed the film crew to work off the ground which made it much quicker to film. We could not operate it at full stroke because we started to make some of the children sick. Paul was able to get every shot he needed.”
For that stage work, the bus was surrounded with two rings of Mimik lights above and below the vehicle, which provided the effect of flickering, moving light. “Then,” says Noble, “we also had big flame bars on tracks either side of the bus that we would run down the bus. We were burning quite a bit of propane in there as well, which gave us great lighting and flame interaction.”
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