Matt Aitken on Infinity War and Endgame
Matt Aitken, Weta Digital Visual Effects Supervisor for Infinity War and Endgame, worked on four MCU films and was “an avid audience member” for the others. He talks with VFX Voice about Weta’s work on the final two Avengers movies, which took the franchise’s advancements in visual effects to a new level.
VFX Voice: What was Weta’s main work on Infinity War?
Matt Aitken: Weta Digital was responsible for the 3rd-act battle sequences on Planet Titan — the Q-Ship crash, Iron Man, Doctor Strange, Spidey, Star-Lord and company planning the attack on Thanos as well as the extended fight with Thanos on Titan and the deaths of most of the heroes on Titan once Thanos gets the last Infinity Stone.
VFX Voice: How did you build Thanos to deliver such an emotionally and physically compelling performance in Infinity War?
Aitken: We made significant refinements to our digital character pipeline for Thanos. A lot of this work focused on making sure we could accurately re-create Josh Brolin’s performance on Thanos. We built two facial puppets, one of Josh Brolin and one of Thanos, each with a complete facial animation system. Our process involved solving the captured performance motion onto the Josh Brolin actor puppet first, which allowed us to check that we were matching the live-action performance accurately. Once we were happy with the facial animation on the actor puppet, we migrated it across to the Thanos puppet. We carefully calibrated the two puppets to allow for seamless migration of the actor’s performance onto the character. Getting this calibration right was challenging technically and involved the use of forensic data to accurately capture the density of facial tissue between the skin and the skull at various points across the head. Once that calibration was complete, the process of migrating the performance onto the character puppet was straightforward.
VFX Voice: You were also called on to do large-scale destruction events for Infinity War.
Aitken: [This included] the Q-Ship crash and Thanos pulling a moon down onto Iron Man, a sequence that became iconic. The challenge in creating this sequence was the huge scale of the event. The Russos referred to this as a ‘global destruction’ event, and the atmosphere on Titan is filled with dust and debris for the rest of the movie. Our destruction pipeline is set up to facilitate animation-driven timing and overall shape of events like this, so our animators can define things like the speed and scale of the meteors and the speed of the shockwave that propagates when the largest meteor hits the ground. Then the FX team takes over to add simulations for the heat shield effects, fire, smoke and destruction, using the distributed sparse volumetric solver within our in-house simulation framework called Synapse. Synapse is ideal because it allows us to distribute our sims over multiple machines, which means we can preserve a very high level of local detail across this large-scale event while still adhering to a tight production schedule.
VFX Voice: What else did Weta work on in Infinity War?
Aitken: We developed the look of Iron Man’s new Mark 50 Bleeding Edge suit with its nano-tech particles, which we generated with procedural geometry. We also designed the look of the blip effect when Thanos uses the Infinity Stones to turn half of all life in the Universe to dust.
VFX Voice: What were some of the challenges of Endgame?
Aitken: Our first shots in the film are of Thanos’ H-Ship attacking and destroying the compound, and our work goes through to Tony’s snap and his death from the effects of the gauntlet. The end battle sequence posed several unique challenges, not least of which was the large cast of digital characters.
VFX Voice: For the final battle in Endgame, you had to deal with many heroes and villains.
Aitken: On our heroes’ side, we have pretty much everybody who has ever appeared in an MCU movie join the battle. In total, there were 47 hero digital characters in the end battle. All of them had to be available as hero digital assets, including high-level digital doubles of the live-action characters. Thanos’ army is entirely digital, including the Black Order, whom we had to prep for dialogue. Thanos needed to have a compelling level of presence, and we had to be able to identify with his decisions at an emotional level for the narrative to work.
VFX Voice: What was the single most complex shot in Endgame?
Aitken: It appears in the sequence where the two armies charge one another and clash for the first time. It’s 45 seconds long, primarily CG, and takes place in a fully CG environment, but also incorporates three separate plate elements at various moments throughout the shot. The shot includes many complex VFX simulations.
VFX Voice: What were the challenges of creating the bombed-out environment?
Aitken: At the studio’s request, we replaced the set with a CG environment that included building rubble, wrecked cars and chunks of concrete. The extra work also had the benefit of allowing us to take over lighting the environment, so we could replace the set key lights, which are necessarily somewhat overhead, with a low, raking, distant sun bleeding through the smoke left by the attack. It also freed us up to modulate the environment lighting in support of the emotional dynamic of the sequence – sunny before the attack, and then after the compound is destroyed, it’s overcast with a pall of smoke and dust hanging over the area. When the portals open up the battlefield becomes brighter again.
VFX Voice: How was Thanos different for Endgame?
Aitken: Thanos on Titan, in Infinity War, was somewhat of a philosopher, meditating on past actions. This Thanos is dressed in armor and ready to do battle, and his motion had to reflect that. Motion capture from Josh Brolin and the stunt team gave us a great starting point for his body motion. We heavily augmented these performances using keyframe animation to make sure he always felt believably heavy and, at the same time, agile.
VFX Voice: What about the work on his face?
Aitken: We added refinements to his facial rig to get around some shortcomings that we had experienced on Infinity War but didn’t get the chance to fix during production on that show. In particular, we added more control to the corners of his mouth. That was an area that we had to develop a work-around for in order to get the detail correct on Infinity War, so we took the opportunity to apply that fix between the two shows.
VFX Voice: How did Deep Shapes help you?
Aitken: We used some new facial tech that has been developed recently at Weta Digital – a tool called Deep Shapes to add further complexity to Thanos’s facial performance. Deep Shapes adds another octave of detail to the facial performance without requiring any extra effort from the facial models team or the animator. These additional shapes are derived analytically and applied procedurally. They are not a simulation. Deep Shapes adds complexity to the way one expression migrates into the next, but the start and end of the transition aren’t affected, so the animator still retains control over the shape of the face and the facial performance can’t go off-model.
VFX Voice: What improvements were made to the blip effect from the end of Infinity War?
Aitken: We redesigned the techniques we had designed to generate the blip effect, both to add support for the vast number of blip events that occur when Thanos’ whole armor disappears, and to add much greater visual complexity to the look of the effect in the long, lingering shot of Thanos blipping away.
We dealt with the large number of blip events in the shots where Thanos’ whole army disappears – a part of the movie we called the mega blip – by coming up with a couple of different level-of-detail solutions. For background blip events, we created a version of the blip that ran in Eddy, a volumetric simulation and rendering tool that runs in Nuke. The Eddy blip solution allowed us to turn around many blip events very quickly.
VFX Voice: Were there visual effects you were able to achieve in Endgame that weren’t possible in Infinity War, even with one film production following right after the other?
Aitken: There were improvements to our tools and techniques, which resulted in a lift in the quality of the visual effects we delivered on Endgame compared to Infinity War.
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