Ready Player One is set in a world that is so dreary people flock to virtual reality in an effort to escape their problems. But it turns out VR didn’t just drive Ready Player One’s plot line; it was also an essential tool for the film’s production.

On Friday, HTC VIVE shared a behind-the-scenes look at the making of the hit Sci-fi flick and how the crew used VR headsets to create the fantastical world known as the OASIS. The two-and-a-half minute featurette shows legendary director Steven Spielberg utilizing HTC Vive devices to quickly view and edit the digital landscape.

“I needed to know where to put my camera, so they created an avatar for me that you never get to see but my avatar had a virtual camera,” Spielberg says. “I could either do frame grabs or I could do actual shots by walking through the virtual sets […] I’m getting shots on a V cam in a V world. This is crazy.”

It’s an interesting look at the evolution of film technology and how VR can increase a director’s role in creating computer-generated environments.

“The cool thing about the VIVE, is that [Spielberg] could say, ‘I don’t want that. Move that out of the way’ or ‘Remove this,’” said Grady Coffer, Ready Player One’s visual effects supervisor. “And in real-time, an artist […] could just make adjustments kind of on the fly. It’s a really interesting way of designing shots and designing your sets in real-time.”

You can check out the featurette above.

Ready Player One, which was released on March 29, is now in theaters.