When Alex Garland’s Ex Machina was released earlier last year, fxguide spoke to visual effects supervisor Andrew Whitehurst from Double Negative about the making of Ava - the A.I. robot played in the film by Alicia Vikander. The live action performance was augmented to add in, via VFX, robotic elements to various body parts of the actress. Now, Ex Machina is in the Visual Effects Bake-off for the Academy Awards, and we have a special breakdown from Dneg of the work, plus some more insight from Whitehurst.
fxg: A hallmark of Ava's rig was that it had to be incredibly flexible and adaptable for different shots - can you talk about how that approached changed over time and how Dneg adapted to it?
Whitehurst: We had three main issues with tracking Alicia. First, the the shots were very long which allows extra audience scrutiny of the work. Second, Alicia's movements are very subtle and graceful, which requires a much higher level of precision in the track than a more action-centric performance. Third, the anamorphic lenses used on the show had considerable optical quirks in the way they distorted space in areas in front and behind the focal plane which meant for parts of Ava that were out of focus we needed to warp the rig in the same way that the lens was distorting the space in the plate. We added more and more controls to allow artists greater freedom to move, warp and distort the rig as the show went on. This was combined with continually revising the working practices for the tracking artists to ensure that the correct tracking approaches were applied to every shot. It was a huge learning experience for all involved and Mark Ardington and Alex Macieira deserve full credit for what they achieved.
fxg: What might be some of the little details Dneg added/removed/augmented with Ava that people could look out for, such as costume tweaks or fixes, but also things that made Ava's effects even more seamless?
Whitehurst: The costume Alicia wore was carefully tailored by Sammy Sheldon-Differ so that areas we knew would remain in camera had the most work done to hide the seams and get a perfect fit. Areas such as the torso, which would always be CG, had more flexibility to not be so perfect. That said we did a fair amount of work in taking out large wrinkles in the costume, especially around the armpits in some shots. It was a similar story with the prosthetics on Alicia's face. They looked great but at the extremes of movement, head turns etc, we would get unsightly creases that required paint clean up in post.
fxg: This wasn't a huge budget film, but it clearly required an advanced approach to the visual effects for Ava - is there anything you would have done differently, looking back?
Whitehurst: I think the area I was expecting to be toughest before we started was in the lighting, look-development of the CG, and the integration of the CG into the plates. Paul Norris's 2D team did great work in this regard. Ultimately though, I think the toughest challenge ended up being the body tracking. Knowing that now, I would probably have gone to town a little more with more tracking markers on the costume, in this instance more probably is better. I actually think we could have added more and not created distractions for the actors, which was a concern for us. If there's ever a sequel we'll be ready!
fxg: What would you say was it that made the visual effects for Ava so convincing?
Whitehurst: I think that because VFX were part of the whole production process from very early on meant we were able to work with all the other departments on the show to get what we required to do our job to the best of our abilities. From the make-up, costume to lighting and camera we ended up with a full range of HDR lighting for every set up, a costume that had appropriate tracking markers built into it, and a costume was constructed to minimize seams in areas that would remain in-camera (the shoulders for example). Team work and deep collaboration were key. If I as a supervisor can't give the VFX artists the best material to work with, you can't expect to get great VFX out of them.
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