Weta Digital VFX Supervisor talks about polygons and eyeballs on Alita: Battle Angel.
Words by Paul Hellard
VFX studios Weta Digital, DNEG, Framestore, Rising Sun Pictures and Lola Visual Effects worked their VFX magic on the sets, environments and characters of Alita: Battle Angel. Gentle Giant Studios and Captured Dimensions provided a lot of the 3D scanning technology required on the production.
I spoke with Eric Saindon, the VFX Supervisor at Weta Digital, for this Alita: Battle Angel story last month in Wellington, New Zealand. Saindon began work at Weta Digital in 1999 as a creature/character supervisor where he was pivotal in the creation of Gollum for The Lord of the Rings: The Two Towers. Eric was a Digital FX Supervisor on King Kong and then became a Visual Effects Supervisor for X-Men: The Last Stand and Avatar. He oversaw the pipeline development for Avatar and supervised 745 shots. For The Hobbit trilogy, he handled pre-production and on set duties as well as serving as VFX Supervisor for the entire trilogy.
Saindon tells me he had an initial meeting with James Cameron and Jon Landau in LA around 2005. He knew it would be for either project in their future. Avatar or Alita: Battle Angel. In the late nineties, Guillermo Del Toro had recommended to Cameron a short anime film based on the nine-volume, cyberpunk Manga series Gunnm by Yukito Kishiro.
“Jim had spoken about Battle Angel and had a lot of artwork, the script for the manga concepts. He’d really kicked it into gear,” said Saindon. “It came around again, back in 2015 and Robert Rodriguez was directing. James Cameron gave Rob Rodriguez the Alita: Battle Angel movie to direct, so he could have room to continue the direction and production of the upcoming Avatar sequels. And for the longest time, there were only three or four others on a set with actors doing scenes in the capture stage. The bulk of the crew came on maybe two years ago.”
Using a performance capture system that has evolved significantly in the decade since Avatar, Rosa Salazar’s on set performance as Alita was captured with extraordinary detail. The setup included a dual camera facial capture setup and a suit that Weta Digital designed to capture Rosa’s breathing so they could incorporate that into their Alita. Robert Rodriguez directed Rosa onset interacting with the other actors, ensuring a performance that was rich and full of emotion.
The film was shot at Robert Rodriguez’s Troublemaker Studios in Austin, Texas. The studio features a 96,000 square foot backlot which was set up to be ‘Iron City’, one of the key locations of the Battle Angel story, about the size of four city blocks and full of Iron City landmarks.
“We would move our performance capture volume around every day, setting up to capture enormous exterior performances,” explains Saindon, “And we also had a performance capture soundstage similar to what Weta has here [in Wellington] where we’d do more straight up performance capture for the various sequences which were wholly CG.”
POLYGONS AND EYEBALLS
The size of Alita’s eyes has been a main point of curiosity in the lead up to the film’s release and are certainly a defining feature of her face. The filmmakers wanted to stay faithful to the way Alita’s eyes are depicted in the original manga, so great detail was put into their design and construction. Alita’s eyes were nine million polygons each – by comparison, Gollum had only 150,000 polygons to make up his entire character!
Alita’s hair and grooming also required high levels of detail. In total, there were 47 complete hair grooms created for Alita, including the styling of her eyebrows and eyelashes. There were over 132,000 hairs on her head, 2,000 eyebrow hairs, 480 eyelashes and almost half a million fine ‘peach fuzz’ hairs on her face and ears. Her wardrobe consists of 71 different pieces of digital clothing which she wears in 125 unique ways. And the detail went well below the surface, Alita’s Cyberdoll body early in the film is made up of over 8,000 digitally handcrafted pieces.
In prepping for this story, I read a lot of reports saying it’s all about the eyes but Eric tells me there’s a lot more to the film than Alita’s eyes. There is the environments, the battles and all of the other complex CG characters that were created using a combination of performance capture and keyframe animation techniques.
“Alita is completely CG,” confirms Saindon. “There are so many tiny twitches in Alita’s face for instance, that make the performance ring so true. We’re so used to seeing mannerisms in people’s faces, we don’t notice these are there, but when they aren’t there, we can sense something is missing and the performance suffers for it.”
To ensure the fidelity of Rosa’s onset performance was preserved, Weta first transferred Rosa’s live action performance onto a digital model of Rosa Salazar. This way, they were able to ensure the performance was played out faithfully before transferring it to the CG Alita character. Weta’s animation team uses Autodesk’s Maya as the base software when creating these performances in combination with a large array of proprietary software and tools. In total, it took 432 million hours of render time to complete the film.
Another challenge in Alita: Battle Angel was to build all of the amazing environments. To create Iron City, green screen elements from the onset shoot in Texas were integrated with digital assets and extensive set extensions. The digital areas of Iron City were built using OSM data from cities such as Panama and Grenada. The artists laid the pieces out to depict the way Iron City appears in the original manga while adhering to the OSM data of industrial areas, high-rise, and administrative areas of real cities.
There were thirty or forty basic building blocks and these were dressed out immeasurably with pipes, aircon units and coloured in different ways. A technique called instancing allowed it to only have to rendered out once. However, some of these city scenes took a week, per frame, to render.
Driven by some of the best environment and matte painters in the business, like Lead Production Designer Dylan Cole, his trademark landscapes are all over this movie’s amazing vistas.
A movie gains a sense of dimension and true depth when it is rendered out in native stereo. “If anyone gets the chance, please go see Alita: Battle Angel in its full 3D version,” says Saindon. “A native 3D production is pure immersive cinema, and not many people are doing it anymore. Watching a post-converted 3D movie is just not worth the effort. This is a shame and I think this is what is ruining 3D for cinema-goers.”
Gunnm (pronounced ‘Gun Mu’) was the name of the concept behind Alita: Battle Angel, a mix of two kanji words, which basically mean ‘gun dream’ .
The Alita character began as an ‘extra’ in Yukito Kishiro’s “Rainmaker” manga comic which was aimed at office workers. All the elements of the story were nods to the cyberpunk craze of the day. “It was the optimum way to depict the inner psyche while pursuing my own brand of sci-fi Cyborgs,” explains Kishiro. “The Scrapyard and Tiphares are all metaphors for modern society, but I’m not drawing them to criticise anything specific. The Scrapyard is a world where every value system has broken down. There are no legends, myths or ideologies. We are living in that kind of world right now. And the important thing is to not criticise the rights and wrongs of it, but merely to see it for what it is: the contrast between inner naivety and harsh reality. Once aware of that, the struggle is to not be nihilistic or cynical, but to live on. That’s not a flight of whimsy, but the force of will, and the true meaning of the battle to maintain individuality. That’s what I wanted to depict in Alita.” — Yukito Kishiro
© Paul Hellard – VFXScience – 2019