Brainstorming Hot-Air-Balloon High Jinks in THE AERONAUTS

By IAN FAILES

**Pilot Amelia Wren (Felicity Jones) with weather scientist James Glaisher (Eddie Redmayne) in The Aeronauts. (Images courtesy of Amazon Studios.)**

When The Aeronauts Visual Effects Supervisor Louis Morin met with the film’s producers two years ago to brainstorm how they were going to make a hot-air balloon adventure that pairs pilot Amelia Wren (Felicity Jones) with weather scientist James Glaisher (Eddie Redmayne), he recalls that he was nervous.

“Almost all the movie is an effect,” Morin told VFX Voice, about the Amazon Studios film. “We had to find a way to achieve that. What we created were different set pieces. We had the basket and ropes that we could move around on a rig. We also had a vertical set for a scene in which Amelia could climb up and move around on when she’s on top of the balloon. The director, Tom Harper, was adamant he wanted to shoot as much live as possible with real actors in the shot.”

Scenes in the balloon basket were generally filmed on a bluescreen set.

“Almost all the movie is an effect. We had to find a way to achieve that. What we created were different set pieces. We had the basket and ropes that we could move around on a rig. We also had a vertical set for a scene in which Amelia could climb up and move around on when she’s on top of the balloon. The director, Tom Harper, was adamant he wanted to shoot as much live as possible with real actors in the shot.”

—Louis Morin, Visual Effects Supervisor

Morin knew during that brainstorming session, of course, that his team would ultimately provide a mass of visual effects for sky and ground backgrounds for the inflated balloon, and then fully-CG shots as well, especially for a storm sequence and a scene in which the balloon crashes.

For moments when the characters are in the basket and aloft, the general approach was to shoot them in a practical basket on bluescreen. For the bluescreen shoot, Morin considered utilizing LED panels that would have sky and sun imagery on them, but found that a powerful stage light would suffice.

The balloon travels high above the earth.

“We basically rented the biggest, most powerful light there is on Earth and we had that on set. We also used LED lights to try to create this ambient light you get from clouds. It’s always a challenge trying to match a sun on set.”

—Louis Morin, Visual Effects Supervisor

“We basically rented the biggest, most powerful light there is on Earth and we had that on set,” he says. “We also used LED lights to try to create this ambient light you get from clouds. It’s always a challenge trying to match a sun on set.”

The bluescreen photography formed a major part of the approach to the aloft shots, but there was also helicopter and drone photography. Virtual backgrounds also began practically. They were crafted starting with plates shot using a multi-camera setup. This involved six 8K cameras arranged in an array that were filmed as aerial plates over Louisiana and then stitched together by Framestore, which also crafted many of the CG assets and environments in the film (other vendors included Rodeo FX and Alchemy 24).

At one point, Amelia must venture up the side of the balloon in the freezing cold.

“If you’re a DP, a director or an actor, you want to feel this stuff, you want the rain to be coming at you, you want the basket to shake like crazy. All this was done through special effects to a certain extent. But then I also had to find ways to get clean plates. The prep work on this movie was insane – ropes, bluescreen, rain – so I needed to make sure I could deal with that.”

—Louis Morin, Visual Effects Supervisor

On set we had this application called Farsight, which was an AR app,” describes Morin. “We could look at different skies, then press the button, move around, and then you could see what the final scene might look like. That was key for the actors and the DP to know exactly what kind of light source and what direction to aim for. Of course, everything was perfected in post-production.”

The film’s signature storm sequence made use of extensive on-set lighting. Morin admits he wanted to tone down any pulsing lights or practical effects on set so he could handle it in post, but he also appreciated how it helped the cast and crew be immersed in the sequence.

“If you’re a DP, a director or an actor, you want to feel this stuff, you want the rain to be coming at you, you want the basket to shake like crazy. All this was done through special effects to a certain extent. But then I also had to find ways to get clean plates. The prep work on this movie was insane – ropes, bluescreen, rain – so I needed to make sure I could deal with that.”

Cinematographer George Steel with Director Tom Harper filming on the bluescreen stage.

Continuing the practical approach to the VFX, a cold-box set was implemented to portray how freezing it was high in the sky. “Every shot of the actors was also replicated in a cold fridge,” says Morin. “I had my daughter and another person match the face position and camera position and we shot maybe 400 versions of breath that were composited into the scenes. So it was all about getting these pieces and elements, and the more you have live, the less time you need to spend on CG for that.”

Morin says that the whole movie is “one crazy shot,” but he calls out a highlight scene where the adventurers come out of the clouds at one point after the storm.

On location for the balloon’s launch.

“You look at the cumulonimbus and all this is 100% CG. I thought something like a wet bear jumping into a fire might be the most difficult thing in CG, but clouds are really difficult to achieve and are really heavy renders. So, to nail down something 100% CG that looks real, which is very subjective – what is a real as far as clouds go? – was quite the challenge. What the director wanted was for the audience to go, ‘Oh wow, this is beautiful.’ Hopefully everybody feels that way.”