Weta Digital vs. Kong vs. a giant flying serpent vs. an upside down world

OK, how the heck do you make an Earth within the Earth?

At one point in Adam Wingard’s Godzilla vs. Kong, the gorilla-like ape leads several humans starting in Antartica down into ‘Hollow Earth’. This subterranean ecosystem near the Earth’s core—filled with giant creatures and an unusual sense of gravity—is revealed to be Kong’s original homeland.

Weta Digital was behind the visual effects for Hollow Earth. Here, VFX supervisor Kevin Smith and CG supervisor Stephen Tong tell befores & afters how they conquered the unique environments and brought the creatures, including giant flying serpents, to life.

Serpent-time

One of Kong’s first adversaries in Hollow Earth is a group of giant flying snake-like creatures, known as Warbats (referred to as ‘Nozuki’ during production). Kong tackles the beasts in a dramatic wrestling match, which ends with him ultimately snapping off a serpent head and devouring the entrails.

Weta Digital’s Kong model started with a shared asset from Scanline VFX, tailored to suit the New Zealand studio’s pipeline, hair simulation tools and proprietary Manuka renderer. One of the biggest challenges for the team involved significant hair and membrane interaction for when a Warbat wraps around Kong, as well as just dealing with the sheer size of the creatures.

“Kong is a 100 metres tall and the Nozuki is even longer than that,” notes Kevin Smith. “The simulations tend to get a little wacky when stuff gets that big.”

Smith notes that animation supervisor Dave Clayton and his group of animators accounted for the massive sizes in this fight scene, and other shots of Kong in Hollow Earth, in a particular way. “Dave and I made a decision early and sold it to Adam Wingard and [production visual effects supervisor] John ‘D.J.’ Des Jardin that we wanted to bring the cameras up and frame him like an actor and let him act and light him like an actor. I think really helps humanize him to some extent and let you get his performance.”

“But,” continues Smith, “the problem with that is that as soon as you start treating him like a six foot tall actor, you suddenly get unbelievable camera moves because the camera’s needing to move hundreds of kilometres an hour. Keeping everything at a believable scale and making you feel his bulk and the scale to the world around him was often tricky.”

Sim-time

There were several simulation requirements on the show for Weta Digital. Early on, we see Kong take a ‘shower’ in a waterfall in what turns out to be a containment facility on Skull Island. For shots of the water running off his fur, effects artists generated per-frame point caches off of a primary water simulation when it interacted with Kong.

“Those point caches would then drive some of the properties of the groom as well as the shader parameters of the skin and fur,” outlines Stephen Tong. “You could see how Kong’s fur and skin changed as the water ran down on him—the groom became clumpier and the fur and skin had more shine and pings on them.”

Later, during Nozuki fight, Weta Digital had to tackle tree destruction, on a huge scale. “The effects department did an amazing job of pre-simulating a lot of tree destruction where Kong would swing the Nozuki around,” says Smith. “As soon as any part of that monster, which weighs hundreds and hundreds of tonnes would hit a tree, it was like hitting a home run. The tree would just be gone or they would just explode into toothpicks. It’s always about balancing the reality against getting a visual result that you want.”

“Tree destruction is really hard to do,” offers Tong. “Especially with the sheer scale of the creature. Visually, when he knocked down some trees, it might look like 20 trees, but when you look at it from a diagnostic angle, it actually meant hundreds of trees.”

Smith recalls one such tree shot, which sees Kong entering Hollow Earth and slide down a mountainside, catching himself by one had at the end. “We called that one, ‘The Big Kahuna’ because that was one at the very beginning where we were like, ‘Ooh, that’s going to be hard.’ There were 600 simulated trees in that shot and it doesn’t seem like it. It seems like only a few trees, but he’s so big and he’s sliding down a kilometre of hillside. To populate it enough to make it feel dense like a jungle, it needed to be hundreds and hundreds of trees.”

There is no sun in Hollow Earth

An enormous amount of terrain-building was necessary for Hollow Earth, which also had to be lit having regard to there being no sun in that environment. Instead, volcanoes and volcanic clouds became a light source, although Weta Digital admits that significant creative license was taken here.

“We mostly kept the ‘sun’ quite low, basically in the middle of the two worlds,” says Tong. And then we’d just find an angle that looks cool in the shot.”

Part of the lighting challenge, too, was the fact that creatures could inhabit both the floors and ceilings of Hollow Earth, as Smith explains. “There were so many times where we’d be looking at stuff in dailies and you go to turn yourself upside down—‘Does the ceiling look right? I can’t tell.’ We always ended up using the flip switch in our review software to check.”