“We had to blow away a large portion of his face, and we were worried about ratings."

Guardians of the Galaxy Vol. 2 opened to a whopping $145 million at the North American box office over the weekend, and as the film debuted, VFX conference FMX concluded with a sneak peek at the extensive work, which was shared by roughly a dozen VFX houses around the world, including Weta Digital (headquartered in Wellington, New Zealand); Framestore (London); Trixter (Munich); and Animal Logic (Sydney).

Among Weta’s mandates was to create Ego, Star Lord/Peter Quill’s father, played by Kurt Russell. “He can create an avatar of himself so that people can relate to him, and that avatar can change into different people, at one point David Hasselhoff,” Weta’s VFX supervisor Guy Williams explained, noting that to achieve this effect, Weta had to create a digital double of Russell as well as of Hasselhoff.

“At one point, we had to blow away a large portion of his face, and we were worried about ratings,” he continued. “We needed a solution that was visually compelling but not too gory. We relied heavily on fractals [and used math to create the look] to make the destruction areas not look very biological, because we could get away with it as long as it doesn’t look like a human. We removed parts of him and then had them grow back.”

Another issue, which now faces all VFX houses, is the sharing of work on VFX-heavy tentpoles. Weta didn’t work on the first film in the series, and it was VFX house Framestore that created Rocket, as well as Groot, and for this film, Baby Groot. But Rocket still needed to appear in many of Weta’s shots, and so the VFX artists had to get up to speed on animating the creature.

“We could do a talking raccoon, but it wasn’t Rocket,” explained Williams, adding that Framestore supplied their Rocket asset for this work. “What’s happening, more and more, is how much of the facilities are working together, even though we’re competitive. Our Rocket fur is hair-to-hair accurate [with Framestore’s Rocket]."

Then Weta hand-animated Rocket, based on the voice performance of Bradley Cooper and the movement of Sean Gunn (who played Rocket on set, and also played Kraglin). "Rocket's performance is based heavily on his breathe, he scowls all the time, and he has a hunch," said Williams.

But according to the two-time Oscar nominee, the biggest challenge for Weta was the Planet Hollow, a spider web-like environment with a look that was heavily influenced by artist Hal Tenny, who collaborated with the filmmakers.

“[Director] James Gunn preferred an environment based on Hal Tenny’s work, and Tenny is a fractal artist,” explained Williams, meaning that Tenny uses math to create patterns. “The problem is you can’t control fractals, and filmmaking requires control. We had to figure out how to use the foundation of fractal math but bend it for what was needed for motion picture production."

About 80 percent of Weta's work in the film appears in this "mechanical yet organic" environment, the VFX supervisor said, "and we don't sit in one place. We had to move around, and it's eight kilometers [five miles] across. So we had to build a high-res CG environment.

“Even after all this effort, there still wasn’t enough detail, because we couldn’t get too close to those surfaces," Williams continued. "For the same reason fractals are hard to model, they are hard to texture. We came up with a methodology of using what we call ‘plague,’ meaning we were growing coral-like structures all over Hollow.”