To create the high octane aerial “Barrel of Monkeys” sequence in Disney and Marvel's Iron Man 3, the production enlisted the Red Bull Skydiving Team to play the roles of civilians, who after an attack on Air Force One, are sent free-falling to earth as Iron Man attempts a dramatic rescue by scooping them up one by one.
Aiming to maximize the realism, visual effects supervisor Christopher Townsend and second unit director Brian Smrz choose to shoot it as an actual freefall sequence rather than using other approaches such as shooting on wires against greenscreen, explained Digital Domain’s VFX supervisor Erik Nash, who himself is an experienced skydiver with more than 1,300 jumps. “Even if you do everything right in those kind of shots, they never have that visceral, frenetic camerawork that you get from actual freefall photography.”
To do this, the production recruited the Red Bull Skydiving Team, who played the civilians. Additionally, one was a stand-in for the CG version of Iron Man -- and another was the camera operator, shooting the scene while free-falling and wearing a helmet-mounted Red camera.
Those portraying the civilians jumped wearing business attire with parachutes beneath their costumes. “You meet them on Air Force One and a couple of them even have dialog to establish the secondary characters and their faces,” explained Nash. “Then instead of stunt doubles, they are the people who you were introduced to onboard the plane.”
Smrz worked closely with the team; the sequence was prevized and rehearsed in the required formation of the rescue before filming. “They were actually flying into the formations [seen on screen],” Nash related. “They’re all professionals that have thousands of jumps."
“The other thing that really amazed me is they did this without goggles,” Nash recalled, likening free-falling to being in a 120mph windstorm. “It really dries you eyes out, and they did this, sometimes eight times a day.”
To shoot the sequence, the team -- including the proxy for Iron Man who wore a red and gold jumpsuit -- jumped from about 12,000 feet (“about as high as they can jump without oxygen”) and did seven to eight jumps per day for six days, at different times of day and in different lighting conditions in North Carolina.
Other than the jumpers, just about everything else was altered using visual effects.
Since the story takes place in Miami -- and required consistent weather -- all of the backgrounds needed to be fully or partially replaced. Also the jump plane that was used for the shoot became a CG version of Air Force One.
The toughest part for Nash involved the skydivers, who had to be rotoscoped out of the original photography. “All of the edge work -- the flapping hair and fabric of their wardrobe -- was the most daunting rotoscoping and compositing task that I have ever had involvement in," he said. "They also had wardrobe over their parachute packs, but in a lot of cases you could still tell, so there was a lot of paint work."
The CG version of Iron Man was composited into the shots and was made “to look as if he is in control and driving this process of collecting the free-falling people. … Additionally there was a lot of paint work to get rid of the Iron Man proxy when he covered up the other sky divers.”
As to the rest, Nash related, “there were only a few instances where digital doubles [other than the Iron Man character] were used, when we didn’t have enough of the Red Bull team in the frame for the given shot -- 90-95 percent of the people on screen in that sequence are the actual skydivers.”
The conclusion of the shot -- as they slow down -- was done on wires, again requiring meticulous work. “All 14 of the stunt people were hanging on wires, so the photography looked like a marionette show,” Nash said. “We had to get rid of the wires, and a lot of wires crossed over other performers. It was very time-consuming work.”
Digital Domain completed roughly 300 shots in total, of which about 250 ended up in the movie, and was one of 18 VFX vendors.
More of the visual effects work in the film will appear in an upcoming post in Behind the Screen.