How Christopher Nolan recreated a nuclear bomb explosion with no CGI

New movie Oppenheimer makes use of 'big-atures'

Nolan famously foregoes CGI, in many of his movies' key scenes, preferring to build elaborate practical effects set pieces in a bid to boost the realism factor.

In an interview with Total Film magazine last year, Nolan explained that "recreating the Trinity test without the use of computer graphics was a huge challenge to take on."

The Trinity test took place in New Mexico in July 1945, roughly a month before the U.S. dropped atomic bombs on Nagasaki and Hiroshima. It was the first-ever detonation of a nuclear weapon and it's central to Nolan's new film, which focuses on American theoretical physicist J. Robert Oppenheimer, who played a key role in the Manhattan Project and is often referred to as the "father of the atomic bomb."

More recently, Total Film spoke with longtime Nolan collaborator Scott R. Fisher about the challenge and logistics of recreating such a massive explosion. The new interview provided surprising new insights into the process by which Fisher and Nolan brought the Trinity test to the silver screen.

One factor, for example, was the use of camera trickery in the form of "big-ature" explosion shots, Fisher explained. In other words, the team created massive explosions, but the proximity of the camera made them seem even larger on screen.

"It is like an old-school technique," Fisher said. "We don't call them miniatures; we call them big-atures. We do them as big as we possibly can, but we do reduce the scale so it's manageable. It's getting it closer to camera, and doing it as big as you can in the environment."

Recreating the world's first nuclear explosion

Fisher also detailed the materials the Oppenheimer film crew gathered to produce the explosion, which was filmed at Los Alamos, New Mexico.

"It's mostly gasoline, propane, any of that kind of stuff, because you get so much bang for your buck," Fisher explained. "But then we also bring in stuff like aluminum powder and magnesium to really enhance the brightness, and give it a certain look."

"We did a bit of that on this, because we really wanted everyone to talk about that flash, that brightness. So we tried to replicate that as much as we could," he continued.

The real-life Trinity explosion had a TNT yield of roughly 25 kilotons. To put the Oppenheimer film crew's ambitious task into perspective, that explosion created a 600-foot-wide (182 meters) fireball that shattered windows 120 miles (193 km) away, decimated trees, and turned sand into chunks of glass. Watch the latest trailer below for a glimpse at Nolan's on-screen recreation of that terrifying raw power.