Did 'Oppenheimer' Bomb Scene Detonate A Real Nuclear Weapon? Nolan Says No CGI Used

"Oppenheimer," the epic biographical thriller film based on the life of the "father of the atomic bomb" J. Robert Oppenheimer, raised the stakes as it featured a nuclear explosion scene without using computer-generated imagery (CGI).

In an interview with the film website Collider, "Oppenheimer" director Christopher Nolan revealed they recreated the world's first atomic bomb test without the use of CGI, emphasizing his preference for practicality and his dislike of digitally-altered scenes.

No actual nuclear bombs were dropped for the film, but Nolan worked with his visual effects supervisor, Andrew Jackson, to physically recreate the original test using other methods.

The "Oppenheimer" production employed a traditional "Forced Perspective" technique for its nuclear blast scene.

According to Studio Binder, it is a technique "which manipulates human perception" using optical illusion "to make objects appear larger, smaller, farther, or closer than they really are."

Movie Web reported that the fire during the explosion resulted from combining gasoline and propane.

"Oppenheimer" special effects supervisor Scott Fisher said they chose to combine the two fuels due to their high energy output in terms of pyrotechnic aspect.

The film crew also used aluminum power and magnesium to simulate the blinding flash commonly associated with a nuclear explosion.

To recreate the nuclear blast's infamous mushroom cloud, the production team photographed the explosion created by TNT from a multifaceted viewpoint and combined all the shots through computers.

Nolan recalled what he felt during the filming of that particular scene, saying the sensation of hearing the noise and feeling the heat of the explosion brought him back in time alongside the scientists watching the first nuclear detonation in history.

"I mean, I've done a lot of explosions in a lot of films. But there is something very unique and particular about being out in a desert in the middle of the night with a big cast, and really just doing some enormous explosions and capturing that," the director said.

"You couldn't help but come back to this moment when they were doing this on the ultimate scale, that in the back of their minds they knew there was this possibility that they would set fire to the atmosphere. It was pretty amazing to engage in that kind of tension," he added.

The film is based on the book "American Prometheus: The Triumph and Tragedy of J. Robert Oppenheimer" by Kai Bird and the late Martin J. Sherwin. It won a Pulitzer Prize in 2006.

"Oppenheimer" had its first theatrical release at the Le Grand Rex in Paris, France, Tuesday. It is scheduled to release in U.S. theaters on July 21.