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ILM ‘Captain America: Civil War’ VFX Part 1: Digital Doubles and CG Characters

Animation supervisor Steve Rawlins discusses Spider-Man, Ant-Man, Black Panther and other CG super hero characters ILM produced for Marvel’s action-adventure hit.

With the recent release of Marvel’s Captain America: Civil War on Blu-ray and DVD, we look back at some of the tremendous visual effects work done on the show by ILM - Part 2 of this 2-part feature can be found here...

Making digital doubles and CG characters for Captain America: Civil War was nothing new for ILM animation supervisor Steve Rawlins. “At the time of Phantom Menace, there was push to figure out new ways to rig characters so that they would be easier to animate or manipulate, as well as try to figure out a motion-capture pipeline.  The biggest leap since then is with things like skin and fat layers simulations, and putting in muscle rigs.  All of these extra touches increase the level of reality,” he notes. To create complex digital doubles and fully CG characters, ILM’s pipeline employs a combination of software. “Our Zeno package is great for all of the simulation work, modelling and sculpting. We have Houdini as well that gets used. Maya has a great well-tested animation interface. We’ve also developed over the years a toolset on top of the package that we can use.  Rendering was done in V-Ray through Katana,” Rawlins added.

“There was some motion-capture done on set that we used directly,” Rawlins continued.  “There were cases where we weren’t able to get capture but were able to match animate, and there were times where we’d go to the stage in here and capture visual elements we could use, like runs or jumps.  Having good motion-capture can help when you’re trying to problem-solve your characters.”  In addition to newly captured live-action images from a production, ILM has an extensive collection of digital assets they can reference. Says Rawlins, “We had a massive library of reference images, photographs and scans that came through the production which we hung on to for textures and skin.  You want to try to make digital doubles that will intercut with the real characters so they all look as seamless as possible.” 

A key, but sometimes limited part of the digital character production process involves the use of previs. “It’s mostly about story beats, camera angles and screen directions, like a character comes in here and exits there,” Rawlins explains. “One area that the previs generally doesn’t go into is fleshing out performance and motion.  Often the timing isn’t quite there and there’s no real reality because that’s not what it’s trying to achieve. That’s something we have to pickup and try to figure out.”

Scaling Ant-Man big or small presents many obvious challenges. “When Ant-Man was one-to-one, straight live-action shots were used, though clearly we’d be dealing with him anytime he was scaled,” states Rawlins. “There’s a brief action beat in the sequence when Ant-Man shrinks small and is inside Tony Stark’s armour.  That was a big challenge as we had to figure out a design for this interior.  Effectively it was building a model per shot depending on where you were looking in this interior and trying to create visual cues so you could recognize that you’re inside between Tony Stark and the outer plating with all of these internal mechanisms. You have Ant-Man running through trying to sabotage Stark’s suit.  Even though we’re trying to stick to the shot design the whole interior is going to change so we have to reverse engineer the shot to look like the initial previs.”

Ant-Man transforming into Giant-Man presented some unique challenges.  “One of the directions that came from the Russo brothers was the idea of a drunken baby,” Rawlins remarks. “It’s a struggle and painful for him to deal with that size.  Because of the scale it’s hard to capture something like that directly one-to-one and know that it’s going to work.  On our motion-capture stage we did various sessions breaking down the previs.”  Time frame captures that formed the basis of the ‘Disco Shrink’ for Ant-Man were engineered into ‘Disco Grow’ for Giant-Man. “In many ways going from the size of an ant up to a human is much like going from a human to a giant,” Rawlins notes. “The costume grows with Giant-Man, thereby, avoiding the impression that it is stretching. When he was large we had to treat the costume differently in terms of the simulation pass and the level of detail would have to hold up because you would be in way closer.”

The digital Black Panther character offered its own challenges for Rawlins and his team. “There was a lot of work in refining the textures and shaders just to get the look right for Black Panther’s costume,” he describes. “It’s a tricky balance when you are trying to create a suit that doesn’t exist, dialling in that fabric and getting the lighting to play off it the way you want and from the environment it has been shot in. We found if too much light got in it started to look like he was grey, or the way the light kicked off it looked like he had a white T-shirt underneath something black, like chainmail.  One of the things that helped is all of the physically-based lighting that we had such as global illumination.  You’re not in the old days of CG when you were doing everything by hand, adding in lots of light to try to cheat reality. Now you get something where the light behaves in a much more naturalistic manner.”

“Both the actor and the stuntman were on set doing all of the fights on-location,” says Rawlins. “In a lot of cases we were taking those performances and converting them into CG because there was a difference between the proportions of the stuntman and Chadwick Boseman. Often there would be bits of interpretation of trying to get that form to look good.  He had his Vibranium claws that come out from time to time during the course of the fight.  They’re a mechanical device built into his gloves.  The directors wanted to make sure it was clear that when Black Panther was using those, he meant business; that was when he was going after a character to seek revenge. If he was trying to stop Cap from escaping, then the claws would be in.  It was a way to play up the intensity of certain moments and play it back down again in other areas.”

Creating a digital Spider-Man began when the role was cast. Says Rawlins, “Once they cast Tom Holland it became clear as to whom Spider-Man was going to be. We wanted to avoid imitating previous movie incarnations where the Wall Crawler is hitting all of the comic book poses. It was about making him feel more real and awkward, like a teenager. Just simply having Spider-Man not pointing in the direction he was going but being twisted or travelling sideways or going backwards for a moment helped to give you that sense he’s not quite in control but is still skilled and able to get where he needs to go.” 

Capturing the nuances of key Spider-Man details helped the directors get the most out of his appearance in the film. “One interesting Spider-Man detail is his eyes emulate an adjusting camera lens,” Rawlins describes. “It was a way to relay a sense of his internal focus but it wouldn’t be moving with every single eye dart and eyebrow flinch.”  A combination of comic book and real life references served as a guide for the iconic webbing.  “There was a certain type of webbing, with a particular way it curls around, which they liked and wanted to get,” he adds. “We had a simple animation tool that allowed us to fire out a simple looking web so we could control timing and direction.  From there it went over to our effects team, who would use that curve to drive all of their effects passes.” 

“It’s a skin tight costume, which means that you’re seeing the complete form and anatomy of Spider-Man,” Rawlins continues. “You have the choice of colour.  How saturated is the red?  How shiny is the sheen in the costume versus matte?  The design of the webbing and things like that come into play.  Then there’s also the form underneath, the musculature that defines the costume.  There was a lot of work in terms of taking Tom Holland’s performance, then applying artistic decisions to subtly pull his design towards the comic book artwork, like a minor adjustment to the size of the head or limb length.  There would be a big pass of muscle simulations which were a combination of jiggle, wobble, holding the correct volume, flexing and tensing, and then a cloth simulation pass to try to get some sliding and control the amount of wrinkling.”

Like Ant-Man, Black Panther and Spider-Man, Vision presented his own set of unique challenges. “With Vision there’s Paul Bettany playing the role; he’s in a certain amount of prosthetics and gets a facial pass afterwards that was handled by Lola VFX,” explains Rawlins.  “But then there would be a bunch of shots where he would be a digital double, especially for shots where he is moving around and flying. There was a phasing effect where Vision would go semi-transparent, as if pushing his molecules further apart when he wants to pass through someone.  Or there was an opposite way where Vision would effectively become denser so that he could ram into someone, like they’re being hit by a cannon. There was a visual language in there to figure out. He doesn’t create this huge comic book flying pose.  Vision drifts and glides.  He is more elegant and stoic.”    

Scarlet Witch required a blending of her live-action performance and digital double to effectively capture the visual impact of her powers. “The idea came up that Scarlet Witch could use her powers to do a super jump,” Rawlins notes.  “She has this ability to manipulate things.  Scarlet Witch could direct that force downwards and effectively propel herself up into the air, then take a huge jump, and use the same force to soften the landing at the other end.  In cases like that we would often blend from the real performance of the actress running in the plate into the CG double as she flies up and lands.”  The Russo brothers wanted a slightly different look for the red magic. Rawlins adds, “Most of it came down to trying to figure out the dynamics of how it would move as well as the colourization.  How intense was the red, the brightness of the core and how that would light her up?  We had a few different moments of size when she is manipulating large versus doing something small.  We had a great effects team that would pull together many iterations of the look.”

ILM’s work on Iron Man took advantage of extensive live-action shots of Robert Downey Jr. suspended by wires. “Iron Man had an evolution at the beginning of the production,” observes Rawlins, who was also involved with producing the Mark 46 edition of the armour suit.  “There were plans to make his character move elegantly but we realized that it didn’t look as cool as something with a bit of weight as he lands with a bit of impact and moves his arms to change directions.  It’s a credit to the Russo brothers because they are keyed in to live-action sensibilities.  We were looking mostly at the stuff where it was Robert Downey Jr. suspended on wires moving through the garage - that was one of the first times he was wearing rocket boots and gloves. Robert was out-of-control moving his body around as if he was trying to correct for balance.  That was our reference to get back that sense any direction change Robert had was coming from something he did.  We tried to get a bit of that real world physicality back into him.”

“Each character had its own unique problems,” explains Rawlins.  “With Winter Soldier it was tracking in the metallic arm.  The arm’s proportions for the CG model didn’t always line-up with the prosthetic stunt arm.  Getting it to line-up was a time consuming task.  We have a great layout team here on this show run by Tim Dobbert - they did some amazing tracking work on Black Panther, Spider-Man and Winter Soldier’s arm.  Sometimes we had shots where Winter Soldier’s arm is around Panther’s throat and Panther is grabbing onto Winter Soldier’s arm. You have to account for subtle proportion changes.  You have to keep those fingers grasped tightly around his neck, you have to keep Panther’s hand firmly attached to Winter Soldier’s arm and Winter Soldier’s arm has to be perfectly tracked in to the actors.”

“There were only a couple digital double shots of Black Widow,” Rawlins notes.  “For Hawkeye there would be a lot of work adding in CG arrows as he’s fires at such a prolific rate. Captain America was shot against green screen in daylight. There was a lot of work done by compositors to put him into the airport environment and keep him looking real.  There were a lot of times where we would be adding CG shields and some moments where he’s throwing them or you want to get some extra hits and impacts.  There would be times where he is a digital double for some big stunt or in more distant shots.”

One of the biggest challenges for Rawlins was the creation of an entire CG airport. Explains Rawlins, “Our environment team did an amazing job. It’s not just a tarmac and a building.  There are hundreds of different props.  Then there was tracking the damage through this extensive action sequence.   Things would move around and sometimes new beats would be added.  When we were about a third the way through we got some new previs beats. One involved ripping a wing off of a plane which means suddenly that plane would have to be missing a wing for every other shot after that.  You would have to track all of that. It’s a big huge sequence maybe 20 minutes long and it’s got so many cool little beats in there with different characters facing off of each other.  Giant Man is going to be a big moment as well as a couple of Spider-Man scenes.  Black Panther is a cool character and people are going to dig him.” 

Trevor Hogg's picture

Trevor Hogg is a freelance video editor and writer best known for composing in-depth filmmaker and movie profiles for VFX Voice, Animation Magazine, and British Cinematographer.