Trevor Hogg chats to Iloura VFX Supervisor Glenn Melenhorst about creating digital rhinos and terrain for "Jumanji: Welcome to the Jungle”...
Whereas Robin Williams had to contend with wild animals being unleashed into the real world by a mysterious board game in the original movie, "Jumanji: Welcome to the Jungle” reverse engineers the concept with players getting transported inside of a video game. The action comedy sequel directed by Jake Kasdan ("Bad Teacher”) stars Dwayne Johnson, Kevin Hart, Jack Black, and Karen Gillan plus some digital effects work contributed by Iloura which involved transitions inside and out of the video game, a CG waterfall, jungle set extensions, a digital matte painting for the reveal of Berber City, a CG vulture, and a stampede of albino rhinos.
Before collaborating with Production VFX Supervisor Jerome Chen ("Suicide Squad”) on "Jumanji: Welcome to the Jungle”, Iloura VFX Supervisor Glenn Melenhorst worked on "Ted, The Wolverine” and "Game of Thrones.” "This film differed in that it's not often we are asked to generate full CG sequences. Mostly we integrate our animals into live environments. The scale of the shots was bigger in terms of asset count than any of our previous work.” CineSync sessions took place between Iloura and Chen. "Jerome was great at providing visual feedback, draw-overs and concise notes. During the layout pass of the albino rhino stampede, we started developing look frames for the feel of the environment and the lighting, bouncing between Jake, Jerome and Iloura feeling out the nature of the environment.”
"For the albino rhino stampede we were provided previz which was needed not only for us to understand Jake's vision, but for production to cover the on-stage live action portions correctly,” states Melenhorst. "We not only scoured the web for reference [both animation and form/texture] we visited a live rhino and filmed it walking, and trotting. This was useful to a point in that our rhinos were mostly running at speeds impossible for a real rhino, so it was mostly useful for assessing how the skin and musculature worked. This proved useful for the rigging team. We also photographed it in detail for later texture mapping.”
There was no crowd simulation for the stampede. "It was all keyframed and staged carefully to show the rhinos advancing and growing in numbers. We had an approved gallop which was revised to match individual scales of the rhinos and then, once their paths were blocked in, we added all the idiosyncratic behavior needed to not make the rhinos' action look ‘samey'. Each shot told a new part of the story.”
Boulders & trees
There was no plate reference for the ravine which was entirely CG and required assets such as millions and millions of pebbles, boulders, trees and leaf litter. "We took a field trip to some cliff locations here in Victoria and photographed them to be reconstructed with photogrammetry later,” remarks Melenhorst. "As well, we built assets from scratch in ZBrush
and used library pebbles and tree trunks from Megascans. The assets were passed to our FX team who built a tool in Houdini
to scatter dust, pebbles, rocks and leaf litter based on the feet of the rhinos interacting with the ground environment. We had to make sure in animation that every foot touched the ground which was challenging given the undulating terrain.”
Handling the environment was a challenge because of the scale and detail. "We blocked the entire sequence logically but as is the way of modern filmmaking, shots were moved around, cut and added constantly so our ‘plan' went out the window. We had to be nimble and make sure that what was foreground of one shot appeared in the background of the next so rapid changes to a set that was made of many millions of pebbles, rocks, trees, and cliffs was a real challenge. Creatively, selling a damaged chopper flying at speed being gained upon by slow rhinos was a challenge for the animators.”
Updated canyon workflow
Software and workflow are always being updated by Iloura from project to project. "This was a big step forward in us implementing USD in our pipeline,” states Melenhorst. "That said, we do leverage off tech developed for other movies and TV shows. Some of our rigging tech and our FX tech was definitely adapted from work completed for "Game of Thrones”.” Filmmaker Jake Kasdan had a special request in regards to the lighting. "Even though the canyon is a long, wide unobstructed space, Jake wanted shafts of light and dappled light to play across the canyon floor. We hung vines and the like across to aid in the effect, but they were systematically removed until there were almost none left. This left us with broad sunlight at the top of the canyon and spotty shafts of light below which on paper made no geographical sense; it was a challenge for our lighting team (led by Drew Wood Davies) to nut out.”
Numerous digital doubles were incorporated for the cast members throughout the movie. "Iloura only took on a few: notably the crew inside the chopper for many of the full CG shots, a shot where Ruby Roundhouse (Karen Gillan) kicks a grunt off his motorcycle and a shot where Bravestone (Dwayne Johnson) knocks another off his bike with a lump of wood. While we had models good enough for the distance inside the chopper, we needed to revisit the Ruby and Bravestone models extensively for the closeup work.”
"The albino rhino sequence was the most challenging technically and artistically,” notes Glenn Melenhorst who did not have extensive assets and shots to share with other visual effects vendor. "Not really many in terms of shots, a handful at most with MPC, assets were passed between vendors only on those shared shots and then it was mostly Alembic files and texture maps, or Nuke scripts and rendered frames for later compositing.” Selecting a favorite moment is not possible for Melenhorst. "No, they are all my babies and I can't choose, apart from the still shot of the rhino sizing up Fridge (Kevin Hart) which was very cool! It was a real pleasure to work with Jake, Jerome and the whole VFX crew. It was one of those fun experiences you hope for in VFX.”