How Ex Machina built a better, beautiful, and utterly believable android

By Posted on February 23, 2016 1:30 pm

Every year, five films are nominated for an Academy Award in the “Visual Effects” category. This year, each and every nominee offers its own unique inside look at the amazing tricks filmmakers and their effects teams must use to pull off the visual spectacles that make for a big-screen blockbuster. In recognition of these five films -- and one of our favorite Oscar categories -- we’re putting the spotlight on one “Visual Effects” nominee each day leading up to Sunday’s broadcast, and taking a closer look at what made them stand out.

First up is the sci-fi thriller Ex Machina, which featured an artificially intelligent robot that challenged our perception of what it means to be human, both philosophically and visually.

Director Alex Garland's cerebral science-fiction thriller, Ex Machina, made more than a few critics' lists of the year's best films due to its potent mix of philosophical themes, fantastic performances by its small cast, and visual effects that blurred the line between actress and digital effects. The tense story of a man tasked with determining whether an artificially intelligent robot could pass as human, the sleeper hit made the most of a relatively low visual-effects budget in turning actress Alicia Vikander into Ava, an android with a hyper-detailed body composed of synthetic flesh and high-tech machinery.

The task of bringing Ava to life was a duty shared by Vikander and visual-effects studio Double Negative, the VFX team that took home an Academy Award in 2010 for Inception and another for last year's winner, Interstellar. Where those films required large-scale digital effects that shaped the world around each film's cast, Ex Machina presented a decidedly different challenge for the VFX team in focusing their efforts on a single character's visual aesthetic.

The first step in building a better robot was in deciding which parts of Vikander's body would appear on screen and which parts would be digitally created by Double Negative and the film's other VFX teams.

"We made the decision to try and keep the shoulders and armpits ... for the simple reason that rigging shoulder blades is not that much fun," explained Double Negative's Andrew Whitehurst, the visual-effects supervisor for Ex Machina, in a 2015 interview with FXGuide. "Similarly, we wanted to keep the hands and feet and face because that was the main method of interacting with the environment and the main method of expression. The arms and legs are full CG because we see through them, and the same with the back of the head and neck."

Once the team had decided where Vikander's body would end and Ava's robotic body would begin, the process became quite a bit more complicated than the typical green-screen sequences used in many films.

With so much of the drama in Ex Machina developing through conversations between Ava and Caleb, the computer programmer played by Domhnall Gleeson who's tasked with testing her humanity, the film's creative team wanted to avoid using green screens, motion-capture gear, or anything else that could distract the actors or otherwise affect the authenticity of those scenes. Without the use of those techniques, the VFX team resorted to a painstaking process of re-shooting and recreating every scene featuring Ava and digitally "painting" over Vikander's body with hyper-detailed, animated effects, complete with see-through elements copied from a second, actor-less shot filmed after every scene.

“Ultimately, she’s a machine who is supposed to move and behave exactly as a human would.”

"When [Garland was] finished doing a set-up, we asked the actors to step out, and then we shot a clean pass where we asked the camera operator to mimic as closely as she could the movement that she’d done when the actors were actually there, and that gave us a clean plate," Whitehurst told The Verge in the lead-up to the film's theatrical release last May. "And then when we got into post-production we could track both versions of the shot — the one where she’s in there, and the one where she isn’t — and then paint her out and restore the background behind her.

"Then we could begin to body-track her performance, so we could capture as closely as we possibly could exactly what she was doing on set," he added. "We used that animation data to drive our robot. So the physical movement of her is all Alicia, and the face, the hands, the feet are photographic in 99 percent of the shots."

Although there was never intended to be any doubt as to whether Ava was an android, Garland and Whitehurst avoided the usual visual cues from sci-fi media and real-world robotics, and instead chose to model Ava's internal workings on a blend of high-performance machinery and human anatomy. According to Whitehurst, the VFX team was barred from using robots of any kind as visual reference for Ava's arms, legs, and other body parts created through digital effects. Instead, the team found inspiration in the suspension systems for Formula One racing cars, high-end bicycles, and the frames of lightweight aircraft, among other sources.

All of those technological cues were then blended with structural elements of human anatomy to form the sleek servos and fabricated skeletal frame beneath Ava's mesh-covered skin.

"Ultimately, she’s a machine who is supposed to move and behave exactly as a human would," explained Whitehurst. "All of the muscles we have in there are simplified versions of human ones."

The end result was over 800 VFX shots that serve to make the team's vision for Ava a reality (or a big-screen version of reality, in this case). While that might seem like a relatively low number of shots compared to the typical superhero movie or sci-fi fare, Garland's affinity for long takes that linger on his subjects -- particularly Vikander's Ava -- made most VFX shots less of a sprint and more of a visual-effects marathon.

According to Whitehurst, the average shot in Ex Machina is almost eight seconds long, which is seven seconds longer than the average shot in most films his Double Negative team has worked on. So, while the number of shots they work on for Ex Machina might be low, the total number of frames the team worked their magic on is right on par with some of the larger films in recent years.

The final product of all that work speaks for itself, though ... literally. Vikander's Ava is more than just the most compelling character in a film featuring two other actors at the top of their games (Gleeson and Oscar Isaac), but her android alter ego may be one of the most fascinating representations of artificial intelligence ever brought to the screen.

And if Whitehurst and his team are lucky, Ava just might earn them another Academy Award, too.

The 88th Academy Awards ceremony will air Sunday, February 28, at 7pm ET on ABC.

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