The action-packed third act of
Thor: Ragnarok
brings all of the characters together for a huge final battle in Asgard. The complex showdown was prevised by The Third Floor, and live action for the battle was shot on a set representing Asgard’s Stone Arch Bridge. During post, script changes relocated the action to the more familiar Rainbow Bridge, a colorful, reflective surface on which to place the action.
(See the November.December 2017 issue of CGW for a staff-written feature overview of all the VFX in the film. Also, see the web exclusives section for additional stories detailing the work by Rising Sun Pictures, Method, The Third Floor, and more.)
Building Asgard
Upgrading assets built for Thor: The Dark World, the team constructed an entirely CG Asgard environment containing over 9,000 buildings, mostly laid out by hand. “Our environment artists pretty much built up Asgard from concept,” says Ben Loch, CG supervisor. “We used our Shambles layout tool, in parallel with our proprietary instancing tool, frInstancer.” The team sculpted mountains based on references of the Norwegian Lofoten Islands, and refined the most distant panoramas as digital matte paintings.
The Incredible Hulk
Framestore was granted the incredible opportunity to work with the Hulk for the first time. “The whole team was incredibly motivated to get to the best possible Hulk,” says Alexis Wajsbrot, VFX supervisor. The team used its proprietary Flex and Flesh muscle and skin sliding tools for the task.
“The behavior of the muscles was physically based,” adds Harry Bardak, CG supervisor. “We had a collision system between muscles, then the skin colliding with the muscles, which created small wrinkles.” Built into Framestore’s Hulk rig was a new multi-subsurface system that scattered light through skin, muscle and bones.
Animators brought Hulk to life through keyframe animation. For Hulk’s facial performance, the artists used the blend shapes supplied from past films, enhanced by dynamic simulations. A collaboration with Marvel’s Hulk specialist, concept artist Ryan Meinerding, helped to inform the subtleties of his facial expressions. “We actually redesigned our shot-sculpt pipeline in order to have maximum control and to be able to be very reactive to this feedback,” adds Wajsbrot.
Korg
Taika Waititi’s comedic turn as Korg required the team to devise a CG rock-monster, capable of witty dialogue and performance. Made up of thousands of individual rocks, a complex collision and deformation rig that supported a constantly-moving rock mosaic was constructed.
“We could push the asset to deliver different types of performance, and still get a realistic feel in how the rocks fit together,” says Kyle McCulloch, VFX supervisor. “After the rig did its work, a team of artists went in and really polished how the rocks moved.” Nowhere was the rig’s articulation more critical than in the face. Smaller stones were arranged around Korg’s eyes and mouth, allowing the character to speak and express subtle emotion.
Hulk vs. Fenris
At 23 feet tall, Fenris, Hela’s giant wolf sidekick, dwarfs even Hulk. The animation team used low camera angles and tight framing to communicate the wolf’s immense size. Groomers covered Fenris with around 12 million hairs, which become wet when the two characters crash into the water at the edge of Asgard, in a battle of the giants. “Some of our best animators focused on the posing of both Hulk and Fenris to get the strongest positioning, and we put forward a lot of different options to Taika,” says Wajsbrot. “We even proposed some new shots – one close up of Hulk fighting Fenris in the water made the cut!”
Having close-up shots of the rapid water, and giant CG creatures splashing around in it, made it difficult to maintain clarity for audiences to follow the action but still feel like natural water simulation.
“The first simulations were obscuring our heroes, so it was all about finding the right balance between making the water sim big but still showing the performances,” adds Wajsbrot. “We did push the limit of both our internal water solver flush and our rendering engine Arnold to get the best water sim. We completely rethought how we were mixing spray and foam with the meshed water, using some aeration passes to create white water for better integration.”
Underwater shots included drops of the injured Hulk’s blood; a special consultation with Marvel determined that this should be green.
Mega Surtur
Towards the end of the sequence, a super-sized Surtur, the Titan of Fire, appears to add even more chaos to the epic finale. Heavily augmented with fire and lava effects simulations, Surtur’s prodigious growth spurt elevates him to a height thousands of feet over Asgard. “From the start, Taika felt quite strongly that even though Surtur was planet-sized, he shouldn’t appear to move slowly,” explains McCulloch.
The animation team worked on different variations of performances, working to find exactly the right balance of threat, speed, and scale. They looked at sword fighters, wrestlers, and bodybuilders for inspiration on the shapes and poses to use on Surtur, always keeping in mind his new-found strength and power.
“The brief for Surtur included references to the surface of the sun, plasma, lava, and fire,” adds McCulloch. “The LookDev team spent months partnering with our shader writers, experimenting with a myriad of ways to have something feel huge, somewhat transparent and refractive, while still seeing a visual complexity and surface.” The FX team then built a fire simulation system that could wrap and define Surtur’s body, perform within the space around him, and have the visual scale of detail required to sell how big they were.
Digital Doubles
As Hela gains the upper hand over Thor, the God of Thunder fights back with newly awakened powers that allow him to shoot bolts of lightning from his body. The team modeled, groomed and shaded a very high-res version of Chris Hemsworth that could work both close-up and far away; also working on a muscle rig specially for the arms, and a Creature FX rig for cape and costume.
“For most of the shots, we received plates of Thor fighting in a mocap suit on a blue screen,” says Wajsbrot. “We body-tracked Chris, even though it was going to be mainly CG, as we wanted to keep his face and facial expressions. Regarding the lighting bolts themselves, we used Tesla coil references for the motion, and a Houdini setup in which we were able to art-direct the density and the speed of the bolts on him.”
The team also created a high-res digi double for Cate Blanchett’s Hela, the Goddess of Death, who wore a mocap suit; this had to replaced with a digital version of her costume and a CG headdress. “Her suit had to have impact, and show her as ‘otherworldly’,” says McCulloch. “We used a lot of reference from the original comics for its look development, and it was a process of discovery with the client to work out how to give the headdress a pose and level of performance that complemented her motivation.”
Alongside these larger-than-life characters, Framestore also modeled the Commodore and Statesman spaceships; conjured hundreds of enemy D-Guards to battle our heroes; and if that wasn’t enough, finished with a fire-fuelled destruction of the Asgard environment, in all contributing to 459 shots.