How Hollywood makes characters walk on walls

• Many movies, TV shows, and music videos have called for surreal sequences where the characters are able to walk on walls and ceilings.
• Movies like "Royal Wedding" and "Inception" pulled this off by building a motorized rotating set and capturing all the action with a fixed camera.
• HBO's "Euphoria" employed a new twist to this by allowing a character to walk on the walls while everyone around her remained planted to the floor, achieved using both a rotating set and visual effects.

Following is a transcript of the video.

Narrator: This scene is one of the most iconic moments in "Inception" because the brilliantly choreographed fight happens on the walls and ceiling of a hotel hallway and room.

But it's only one in a long line of these types of shots. From "Royal Wedding" to "High School Musical 3" to Ariana Grande's high-concept music videos, Hollywood has been putting actors on walls for decades. But how do they do it?

We talked to the team behind one of the most recent examples of this type of scene, Zendaya's trippy, drug-induced walk through a house party in the pilot of HBO's "Euphoria," to see how the scenes are shot and how they took things a step further.

The basic concept behind getting a character to walk on walls and ceilings is by building a motorized set and having a camera fixed in place to follow the room's 360-degree movements in sync. An actor moves on the surfaces inside the set, carefully hitting their marks so they don't injure themselves. Keep in mind that the actors are always working with gravity, so their feet will be on the ground, even if the ground happens to be the ceiling. And when the camera is fixed in one place on the rotating set, all the viewer can see is the character moving, as opposed to the entire room, which would look different if the camera were not attached.

The technique is believed to have been pioneered when Fred Astaire wanted to dance all over a room in 1951's "Royal Wedding." The set was built inside of a steel rotating circular structure. Back then, to create the effect from a camera fixed in place, cinematographer Robert Planck strapped himself and his camera to an ironing board at the base of the set, allowing Planck to capture the exact rotating actions of the room while the actor was free to dance right-side up.

Astaire's jacket over here had to be sewn down, and these curtains were actually made out of wood to ensure that everything stayed in place.

Stanley Kubrick showed this type of setup could be used to imitate life in space in 1968's "2001: A Space Odyssey." The rotating centrifuge set allowed the audience to see the world like an astronaut living in zero gravity. The filmmakers were able to show somebody eating upside down simply by gluing the food to an actor's fork. But shooting "2001" showed how difficult it is to bring lights into a set that is in motion. So, for the most part, all the lighting inside the centrifuge had to come from strip lights attached to it along the walls, some hidden and some visible if the camera angle was wide enough.

Now jump to 1986. "Royal Wedding" director Stanley Donen would repeat the trick he helped pioneer when he directed the music video for Lionel Richie's aptly named "Dancing on the Ceiling." They had a motor-powered set for Richie and a few others to dance on, and the action was captured by a remote-controlled camera, meaning the cinematographer didn't need to be harnessed into the set.

But here's where the music video took the technique a step further. For some of these shots of larger dance numbers, the dancers were actually on a stationary set where the floor was designed to look like a ceiling, and they flipped the camera upside down, creating the illusion that they were dancing on a real ceiling. Then they used something that didn't exist during Fred Astaire's time, a blue screen, to bring this together with the image of Richie and his band dancing on the floor, bringing this genre of scene to a new level by showing people standing on two parts of a room at the same time.

"Euphoria" would find another way to do just that, but we'll get there shortly.

Even with new technological innovations, the basics of this technique continued to power dream sequences and musical numbers in everything from "Poltergeist" to "A Nightmare on Elm Street" to "High School Musical 3."

Then 2010's "Inception" created a scene the audience would never forget.

Getting the illusion right now required multiple sets: a horizontal one that rotated 360 degrees, a vertical one where the actors could be lifted up by wires, and a trolley rig that moved the actors around. Despite all the CGI tools available at this time, director Christopher Nolan took a practical route, shooting a fight scene in an environment that was constantly in motion.

And it wasn't just one camera operator with one camera attached to the set. They instead employed multiple camera setups.

One of those cameras was fixed in place on the ground. According to actor Joseph Gordon-Levitt, this made it look like they were fighting on every surface of the room, but without the audience seeing the room itself spin. Another camera was attached to a technocrane, which was not locked into place but moved more independently.

In the years to come, the general illusion was always practical, but CGI allowed for new opportunities. In the "No Tears Left to Cry" music video, Ariana Grande walks through a rotating room and falls through a crumbling wall into another set. In reality, the set was turned at just the right moment so it looks like she is falling through a wall and not the floor.

She jumped out of one of the set's open ends, which was later turned into a crumbling surface.

Fast-forward to 2019's "Euphoria," which added even more twists to the technique.

A few factors made the shoot a big challenge. The camera couldn't just stay in one place, as it had to follow Rue, who is played by Zendaya, down the hallway. Think back to "Royal Wedding," where the shot was always based on the fact that there's one camera that doesn't ever move rotating with the set. There are multiple people in this sequence, and most importantly, while Rue defies the laws of gravity, the people around her do not. Basically, this scene follows two centers of gravity as opposed to just one.

To pull this off, the show's visual effects supervisor, David Van Dyke, worked with Pixomondo's Nhat Phong Tran.

David: You know, it was literally a science project that we had to figure out.

Narrator: 3D models created by the VFX team helped the crew adjust the size of the set before building it. This set was actually a recreation of a hallway from a real house where they filmed the entire house-party scene, meaning it needed to match the actual location, ending with a staircase and starting with this bathroom.

Because the room doesn't start spinning until Rue exits the bathroom, they had to attach a motionless set to the revolving one. On top of that, the doorway between the two sets was too small for the Alexa 65 camera and crane to fit and follow Rue down the hallway. Their solution was to build the bathroom on a platform. This platform would split and move out of the way once Rue stepped off of it and into the revolving area, allowing the large camera and prime lens to push through.

And like with "2001," lighting a scene like this is difficult. So the shot was primarily lit up with these ceiling lights that were naturally a part of the set. To maintain the two separate gravitational pulls, some of the background partygoers were strapped into the floor of the set.

Now, no decision on a rotating hallway can be spontaneous or random. Because the actors were locked into place, the crew had to think specifically about where they were placed in the revolving room. Look at the background, and you will see two people on the left wall, two people on the right wall, and two people in the back. That is no coincidence. According to Van Dyke, that's because weight had to be evenly distributed as much as possible.

David: You have to kind of balance people on both sides. OK? So that it has a nice even rotation.

Narrator: And when shooting one of these scenes, it's crucial to watch out for any element that could potentially give away the whole trick. For instance, for extras that had longer hair, there was the risk that their hair would fall up when they were completely upside down. According to Van Dyke, the crew actually put extra hairspray in their hair to keep it in place.

David: Antigravity hair is not gonna look good.

Narrator: There were a lot of other possible tells that had to be accounted for. This table over here with beer bottles on top of it had to be bolted down tight. Recall that same thing was done for all the furniture Astaire danced around. In addition to the extras who were strapped down, the show wanted to have a few people walking behind Rue. But they couldn't just have them on set walking in a straight line.

Nhat: It was just impossible to have them roped in with the rotating set. Those would need to be shot as a separate pass so that they can walk on the actual normal floor within normal gravity.

Narrator: To do this, they built a new version of the hallway that didn't rotate and filmed a few extras walking down it. This new shot needed to imitate the exact same movements as the revolving room so the extras could be seamlessly added into the primary shot.

Nhat: We have to recreate that same exact camera motion, so we cannot have, like, another take that has a completely different camera performance.

Narrator: It was much more advanced than just holding a camera upside down. For the non-spinning set, they used a motion-control camera, which was programmed to run alongside the extras and imitate the first camera's moves to a T.

And while this set didn't move, it still needed to appear as if it was spinning. To achieve that effect, they had to inverse the hallway's rotation and incorporate that into the motion-control camera's movements. This was helpful because they were hard moves to imitate manually and they needed to be precise. The first couple you see here is moving on an angle, and this extra was completely upside down. Each plate had proper blank spaces taped off for where extras would stand and sit, allowing for these other extras to then be composited seamlessly into the shot.

It's all quite a long way from the blue-screen effect in "Dancing on the Ceiling." Put all these elements together, and you have the convincing effect of Zendaya walking on walls as the surroundings around her remain normal.

Sometimes, creating an amazing sequence for the screen means borrowing from Hollywood history. And that's when those techniques evolve into something fresh. Each iteration might become more and more ambitious, but nothing would be possible without what came before it.

Fred Astaire danced on walls so Zendaya could stumble on them.

Ian Phillips: Thanks for watching. If you enjoyed this episode of "Movies Insider," don't forget to hit the subscribe button. Did we leave off any of your favorite scenes of characters walking on walls? Let us know in the comments.