Trevor Hogg chats with production visual effects supervisor Janek Sirrs, visual effects producer Mitchell Ferm, and visual effects supervisors Adrian de Wet, Stéphane Nazé, Paul Butterworth, and Guy Williams about bringing to the big screen a spinning island, raging monkeys and a futuristic society that stages lethal survival games…
“I’d worked with Francis Lawrence a few years ago on I Am Legend [2007] and we had a productive, and entertaining relationship on that picture,” explains Janek Sirrs who won an Oscar for being a member of the visual effects team responsible for The Matrix (1999). “Francis likes shooting photo storyboards and seems to enjoy [perhaps a little too much] having me embarrassingly play the part of the zombie, the monkey, and the frightened girl for him. Our schedules didn’t really sync up immediately after Legend and so I ended up drifting off into the Marvel universe for a couple of shows before our stars could align again.” The duo was reunited for the cinematic adaptation of the futurist young adult series created by Suzanne Collins about survival games and a civilian revolt. “My teenage girl years are a little bit behind at this point in my life so I can’t really claim to have been an avid reader of the books! Obviously, the first Hunger Games [2012] movie was such a box office hit that it was impossible to not know something of the source material though. When I started on the project, the script was still a work in progress, as is often the case these days. However, the book was always going to be the template for the film so we could refer to that while we waited the screenplay to be polished, and made fit for general consumption.”
Janek Sirrs |
“There are only two major digital environments in the movie which are The Avenue of the Tributes, and the centre portion of the Arena that contains the Cornucopia island,” reveals Sirrs. “The chariots in the Avenue scene were all shot in a big empty parking lot at the Atlanta Speedway, and the only pieces of physical set construction were a partial archway [and immediately adjacent bleachers] that the chariots emerge frame, and the Presidential seating area. Everything else – the other archways, bleachers, crowds, and surrounding buildings were all added digitally. Additionally, we only had six practical chariots so you’re often looking at digital Tribute doubles and horses/chariots in the wider shots. All the water-based action scenes at the centre of the Arena were shot almost entirely at a waterpark outside Atlanta, where we constructed a full-size island, two spoke-like rocky paths leading from it, and a couple of the pedestals that the Tributes emerge up into the Arena on. In the final shots, the entire surrounding ocean water, beaches, and jungle blowing in the breeze have all been added digitally. In general, we were able to get away without using digital doubles for the action sequence as we weren’t asking for the actors to do anything ‘superhero’, or impossible, which would have been out of keeping with style of the picture.”
“The water-based action scenes in the centre of the Arena required a great deal of brute-force rotoscoping,” states Janek Sirrs. “More often than not there were no sensible spots to erect any useful blue screens. 2D artists were compositing in things like fake strands of hair blowing in the breeze to eliminate the low-detail, rounded look that often comes with roto work. In terms of the fully digital elements, the Arena jungle was probably the trickiest. The ridiculous polygon count of all the various individual trees, leaves, and plants meant that there wasn’t enough storage on the planet to keep them all as proper geometry. Instead, all the foliage had to be instanced at render time, which could be time-consuming to say the least. One big aerial orbiting shot over the Arena was so dense that it proved impossible to render at 4K. Frames simply wouldn’t finish!” Less complicated were the desktop graphics and central hologram in the control room which were established by the original movie. “For the Tribute training centre the virtual target technology was inspired some real-world hologram technology that exists today, albeit in a primitive form. By firing three high-powered lasers at the same point in space, it’s possible to ionize a dot of air at the intersection point, and create glowing plasma. Then by synchronizing the movement of those lasers beams, the illuminated intersection point can be moved anywhere in 3D space. Move them fast enough, and you can effectively draw things in thin air. We extrapolated where that sort of tech might get to several years from now. As for the blocky look of the targets themselves, they were inspired by some art exhibits. We saw the potential for the blocks to convey impact wounds without running foul of any ratings issues.”
“Early in preproduction there were conversations about trying to achieve some of the fog shots practically, but the idea was quickly dismissed once we realized how art directed the fog would have to be,” remarks Sirrs. “On location in Hawaii, ever-changing wind conditions would have played havoc with any SPFX smoke/fog machines. In terms of the look and motion of the digital fog, we didn’t want it to feel anthropomorphic, or ‘evil’, as it might in a fantasy picture. It was really supposed to be roiling fog, moving downhill under its own weight. We still had to art direct the leading edge to have tendrils that projected out from the main bank, otherwise, the Tributes would be immediately engulfed the moment it reached them. Integrating the fog into the [real] jungle required masses of brute-force roto work. LiDAR scanning is less than useless in a constantly moving environment of leaves and plants blowing in the wind, so we had to resort to manually isolating the foliage into many layers for every shot, and create a pseudo z-depth map that the volumetric fog could push through.”
Jo Willems |
“The hardest part about the dome destruction was probably deciding how the dome itself was constructed [so that we could subsequently destroy it],” notes Janek Sirrs. “It obviously had to have some sort of superstructure, but then also must be lined on interior with a hi-tech projection system that creates the Arena skies, mountains, and perimeter jungle seen during the games. The outer superstructure was based upon the type of girder roofs you might see at a modern Olympic station, while the projection panels were influenced by the look of a 9-light lighting unit with their Fresnel lenses. Once built it was just (!) a question of running some simulations to get some convincing break-apart action. But then any falling debris from the dome also had interaction with trees and bushes on its way down which of course meant building more digital foliage, and simulating their interaction as well.”
A unique addition to The Hunger Games: Catching Fire is the spinning island. “There’s really no way that one can realistically simulate harsh daylight, especially over a large area, on a stage, states Janek Sirrs. “From the get-go, we knew we wanted to somehow shoot the Tributes outdoors, really turning with respect to the sunlight [so that shadows played across them in cyclical manner]. Steve Cremin and his SPFX team constructed huge lazy Susan rig on which was mounted a generic piece of dressed island rock surface, big enough for the camera crew and the cast to roll around on and perform stunts, and then this whole setup located within a 4-wall blue screen. In the final shots, the interactive rock surface was replaced with a digital version of the island, and the whole thing surrounded with the digital jungle environment, and multiple water simulations for the spray kicked up by the spinning motion. We had initially worried about whether we could spin the rig fast enough to convey a scary enough sense of speed [without the cast and crew throwing up in the process]. Luckily, the chaos inherent in the action meant that we could cheat and do things like spin the surrounding digital world faster than we actually span the lazy Susan.”
Francis Lawrence |
“Francis is a director with the perfect combination of specific vision and collaboration,” observes Mitchell Ferm. “He and Janek had worked together on I Am Legend so there was a level of trust to their relationship that goes back several years. We did animatics for most of our major action sequences and he shot and cut a movie that matched pretty closely without being too restrictive and limiting spontaneity. It’s important to be responsible, but not eliminate the possibility of a happy accident.” Janek Sirrs also impressed Ferm. “Janek brings a level of professionalism that’s hard to match; he’s a meticulous artist with incredible technical knowledge and a great eye, but knows how far you can stretch a dollar, when you get diminishing returns, and how to balance the overall workload. Tough but fair and genuinely interested in creative input from the people with whom Janek works; I never felt like I had to keep him honest and think I made a pretty good sounding board now and then.” Production Designer Phil Messina and Cinematographer Jo Willems were key creative partners on the project. “The Art Department drives so much of the look of the picture and Janek believes in grounding everything in some sort of reality, even if it’s just a reference. There’s little in the movie that’s all CG, so we relied on Phil and the Art Department to establish the look of the world with concept art and partial sets, if not more. Jo was accommodating to our special VFX needs, like establishing a colour bible early in post-production so we could pre-time all of our plates, and incredibly supportive of the work we did, even though we sometimes changed what was captured in camera pretty significantly. Jo was always available to look at an image and push us in one direction or another throughout the process.”
Adrian de Wet |
“I’m not sure what the biggest challenge was, to be honest,” reflects Adrian de Wet. “Perhaps it was the Fog Sequence, which was one of the film’s showcase IMAX sequences. The extra resolution meant that what was already a challenging FX simulation became an extremely detailed and demanding effect, where we really were testing the capabilities of our simulation software. But, again, it was also a challenge story wise, because the scene was shot with the actors running through the jungle without any fog, and then a scene was cut together, into which we had to place the fog. It soon became apparent that the placement of the fog was something that you couldn’t easily change in one shot without affecting lots of others, and it was quite difficult to create a sense of consistency in the speed of travel of the fog. For instance the, actors slow down halfway through the chase and are seen talking to each other, and Mags walks away to her death. We had to hold the fog back but make it appear to be travelling at the same speed throughout the sequence, without having it overtake the actors. We ended up going around a few times blocking out the sequence with a checkerboard plane to represent the leading edge of the fog, until we got something that felt consistent and was in the right place; that was before we’d even simulated or rendered anything at IMAX resolution.” Generally, the sequences were handle separately by the different visual effects vendors. “The only shared shot was a jungle environment shot in the Monkey Attack Sequence. We put in the cornucopia, lagoon and environment, and Weta did the Monkeys. Other than that, we did share assets; we created digital doubles and weapons which went out to other facilities.” A particular cinematic moment was memorable. The Avenue of the Tributes, featuring the fire costume, was the sequence that surprised me. It was the sequence that I was most worried about, at first, because it featured in the first movie and those shots are really hard. They’re full on digital environments, harshly lit, and need to look real. I love showing people the befores and afters of that sequence. I was pleasantly surprised at how quickly those shots came to life, and how early on in the process they began to look great. This is all down to our great team in Singapore.”
Stéphane Nazé |
“For the mansion we extended the building itself so it’s purely a matte painting,” states Stéphane Nazé. “The building was too small for them and the idea was to have something huge. We extended the building on each side. It’s at the beginning where the characters are following the AV to the mansion. It’s a 3D DMP [Digital Matte Painting] and we put in place some CG fountains in three shots and you have one shot of big fireworks in full CG because the idea was to add some more chorography. For the big fountain they came with a reference. It’s a big fountain.” Nazé explains, “You get more of a feeling of parallax on a 3D matte painting than a basic matte painting.” The most complicated effect was the fountain. You have a shot with the fireworks and afterwards you have three shots with the fountains. It’s always the same problem. It’s to be efficient when you have a complicated asset to do only in two or three shots. You have to be clever. It’s not like you build an asset in full CG and can put the camera where you want. You have to find a lot of ideas to have something work within the framing. We put in place some development to build the fountains and to have control in terms of dynamics, speed, and design. For the object itself we did it in a 3D DMP so we projected some texture on it. The water is a mix of a fluid simulation and particles in Houdini.”
Janek wanted the targets to be stylized humanoids that would be animated with real human physics, and when hit by an arrow, would break apart in a spectacular way,” explains Butterworth. “The first challenge was to design them. Janek was interested in the look of Antony Gormley’s sculptures, some of which involve human figures portrayed with cubic and rectangular shapes, and how they would look as holographic projections. Once we had a look there was quite a bit of R&D by the FX team to determine how the cubes would handle the compression and stretching of the humanoid volume as the character animates and also how the characters might be made to shatter. This was complicated by the need to have the holographic characters made out of laser beams that sweep across the arena from different angles and converge to create the holographic volume. The look development needed to include the lasers, as well as the caustic patterns that they leave on the floor where any point of light not being used to form the hologram would be hitting the floor. This made for really interesting lighting interaction with the set.”
Paul Butterworth |
“We probably spent the most time on working out the look of the shattering effect when an arrow hits a hologram,” remarks Paul Butterworth. “This was more about exploring options than overcoming any technical difficulties. We explored whether the cubes break up into smaller cubes or not; how long they exist for once released from the character; whether they bounce against other objects or not.” Butterworth notes, “An interesting continuity task involved keeping track of the arrows in Katniss’ quiver. Whilst Jennifer sometimes had a number of real arrows in her quiver on set she could never actually fire a real arrow for safety reasons, so all of the arrow firing was mimed and CG arrows added. We always needed to make sure she had the right number of arrows in her quiver at any point in time, always accounting for ones that she had fired along the way. You’d be surprised at how long it took to lock the arrow counts down!”
“The monkeys weren’t seen in the first movie,” states Guy Williams. “They’re described in the book so there was design we had to head towards and excellent artwork that had been done before we came on to the project to define what the monkeys looked like. At the same time if we wanted to make it more believable or fierce or the right size in relationship with the kids there was always room for discussion and collaboration.” Under the instructions of Francis Lawrence, two different species of monkeys served as the basis for the creatures which are a lethal threat to the Tributes in the Arena environment. “We had a good visual target and a limited scope of research we needed to do between mandrills and drills. We looked at faces, the way the fur sits, the colouration of the fur, and the length of the hair.” Williams believes, “The Internet is finally the repository of all the knowledge of man. The hardest part of using the Internet is trying to sift through all of the ignorance of it at the same time. You type in mandrill, set the search for a large image, and you’ll find hundreds of pictures of mandrills. As good as the quality of YouTube the majority of videos are captured on cellphones and not all of them are created equal as they have a lower resolution. Anytime we saw someone dealing with a mandrill we looked at that footage. There are surprisingly few long documentaries on mandrills. We ended up using some documentaries on baboons because mandrills are part of the baboon family. One of the things they were keen on was not to have it feel we’re on a stage floor which was flat. It had to feel like we were in a jungle so everybody had to move unevenly. The research was relatively straightforward.”
“We have done a lot of water work in the last couple of years so we have some excellent tools for that,” remarks Guy Williams. “The hair solver would take the hair which was below the water and would let it drift. The hair that would be on the surface of the water would stick to the surface. Adding to the believability was the reflection and refraction of the light in the water. “As they’re thrashing around in the water the water will start to change value based on the aeration of the water, the amount of small bubbles that are too small to simulate but large enough to affect the light contribution so the water starts to go white instead of brown. That stuff helps in getting the water to look right. We raytraced everything so as the monkeys went down into the water you could see them defusing down into the murk of the water.” Hardly any motion-capture was utilized for the project. “We didn’t use any crowd solvers so each monkey was key frame animated by hand. There were no cycles used extensively. We had a cycle for running and jumping but for the most part they had to be changed. The thing that helped the monkeys to be unique was the terrain. The monkeys are not all sitting on a flat surface looking at the kids; they’re on tree branches or climbing down the side of a trunk or jumping off of a tree branch to the ground or running along the ground or jumping into or back out of the water. The difference in action made it so you would never see a monkey doing a similar thing as another monkey. That helped us to keep it fresh and alive. Since each one of those monkeys were key framed they were naturally treated as if they were a hero character.”
Guy Williams |
“They shot most of this on-location in Hawaii,” explains Guy Williams. “A lot of the times they mimed the actions so the kids would learn the fight choreography and do it. We would have to put the monkeys in such a way that it felt like they were interacting with the kids. The plates were shot well. If a monkey jumped into the water they would throw a sandbag into the water so the kid would have a splash to react to even though we would end up replacing the splash with a digital one. For the most part the kids do a successful job of keeping the monkeys at arm’s length. The monkeys have teeth that are very large so if they get close to you you’re in trouble. One time Katniss gets pushed under the water by a mandrill and it tries to bite her while she is under the water. For those shots someone grabbed Katniss’ bow and pushed her underwater. Another time is when one of the kids tackled by a monkey he mimed it. Small performers wearing grey suits would wrestle with the kids so you got good physicality and interaction with person being attacked.” The jungle got digitally enhanced. “The thing I took away from Avatar [2009] in regards to this project is not to be afraid to put down digital jungle to make it better,” states Williams. “If it is a CG monkey going through a practical forest we would put in CG forest within two plants in every direction of where the monkey is going. As the monkey is going through he is brushing against plants and the plants are moving out of the way. Those plants are also brushing against the plants which are next to them. You get this ripple effect in the forest. We ended up building some unique plants and using some from our library to flesh out the rest of it. When the monkeys get into the more open areas you can do things like sand, dirt and leaves simulations.”
“Some of the close-ups were the hardest shots we had to do because they bare no fault,” remarks Guy Williams. “When you’re working on a project like this there is always going to be a shot that ends up being cool. We have these backlit monkeys walking along branches in the foreground looking down on the kids which made for a beautiful shot.” The biggest challenge was the beach scene. “It should have been the water against the fur but it ended up being sand. The problem was it never looked like there was enough so we kept adding more layers of sand simulations to get it to look right. There’s a lot of sand on a beach. We had all of the stuff that was in the sand like twigs and leaves; that stuff worked out well but the real challenge was trying to get the sand to do the right thing. Sand is specific when you put your hand in it and push forward it doesn’t move like a mound. It moves, dissolves and erodes away in front of your eyes. The grains of sand are all sliding together and revealing more sand. To do it right you have to put all of those layers of sand in there.” Williams notes, “Janek has an excellent sense of humour and a dry British wit; he’s fun to talk to just on a social level. To actually get to work with Janek was a blast. The whole team had a fun time.”
“We opted to shoot in IMAX for select portions of the Arena to create a more immersive experience, and to heighten the difference between the artificial game construct vs. the reality of Panem,” states Janek Sirrs. “The [relative] lack of grain in the IMAX material added a hyper clarity to the imagery that tied in thematically with the story. Unfortunately, there wasn’t enough money to film the entire Arena Sequence in IMAX. Or days in the schedule to shoot with those huge, unwieldy cameras! We had to be selective about which scenes would be benefit from IMAX the most, and intermix with a more standard 35mm format that could also match the IMAX 1.43 aspect ratio. IMAX material was scanned at 4K [compared to 2K for the rest of movie], and once it had been digitized there was really no difference between it and 4K 35mm material in terms of workload, and VFX pipelines, merely grain size. We just had to get the Arena vendors used to composing shots for a squarer than normal aspect ratio. As Katniss rises up her tube into the Arena for the first time the picture opens up top and bottom to a much taller aspect ratio, going from 2.39 to 1.43. Unfortunately, the only place moviegoers will see this to full effect will be in the IMAX film theatres, of which there are now fewer and fewer. They’ll still see a reduced version of the same effect in the digital IMAX theatres though. Folks might be intrigued to hear that many movies shoot IMAX sequences often for financial, rather than creative reasons. If a production shoots a specified minimum number of minutes in IMAX, then the IMAX Corporation will guarantee a longer run in their theatres. The higher ticket prices then outweigh the increased production costs but not necessarily the pain and suffering of shooting in that format.”