How do you make a film about terrorists taking over the White House when filming in the capital can be very difficult, if not impossible? Overall co-visual effects supervisor Volker Engel on Roland Emmerich's White House Down answers: "Well, you're very enthusiastic at the beginning and you think you're going to get a lot from aerial photography, and then you do your research and you find out about the no-fly zone which pretty much includes everything that you need for the movie!"
Despite that initial barrier, the film's visual effects team rallied and sought to gain as many real plates of Washington D.C. as possible, with the knowledge that a large CG effort would bring the terrorist action film to life - but without a mammoth VFX shot count. That involved, also, shooting cleverly on sound stages with partial sets and choosing to film mostly without bluescreens through windows and doors (relying on painted backings instead). Live action stunts and outdoor scenes were captured in a park in Montreal next to the Olympic stadium doubling as the White House lawn.See a breakdown of Method Studio's VFX for the helicopter crash sequence.
"We could shoot the Capital Building, say, from one side because it's fairly accessible there," adds co-visual effects supervisor Marc Weigert. "And the White House is also fairly accessible from the north side. We got a bunch of things there for reference and as usable aerial plates. And we had a ground crew shooting in Washington with the Sony F-65 camera plates for driving and static plates for some of the White House and Capital building shots. We also used a 400mm lens on a RED EPIC for aerial shots of the White House. This all matched well to the rest of the film which was shot on the ARRI Alexa."
fxguide takes a look six of the biggest sequences from the film, plus we explore how Washington D.C. was built and delve into the game engine approach used for previs.
Previs with a game engine
Uncharted Territory took a new approach to previs for White House Down, employing a game engine based system. "We built a prototype together with a German company Wonderlamp Industries called Genie," says Weigert. "It hooked Maya up directly to Unreal Engine. The Unreal Engine would be used for realtime rendering of the assets only while Maya, which doesn't really handle lots of polygons in realtime. So we had say car rigs or characters in Maya and it would immediately move the data over to the Unreal Engine so we could animate characters or drive the cars for a car chase sequence and see it in pretty beautiful quality realtime."
This followed earlier work Engel and Weigert had done for Emmerich's 2012, creating previs 'more like you would actually shoot a movie.' "Rather than first storyboard and animate it on a shot by shot basis like it used to be done," recounts Weigert, "we said let's play this as if it's real. So we control our cameras with game controllers. We would first do the blocking of our scene - say a car chase, sometimes at half speed, then we would set the cameras and also control them in realtime and record that in realtime. That way we would get 30-40 second long takes, and it would immediately go into editorial. They would cut it down and then we'd sit with Roland what additional angles he'd like to see."
Building Washington D.C.
Uncharted Territory, headed by Engel and Weigert and aided by visual effects producer Julia Frey, had on previous shows completed many visual effects shots in its own right. For White House Down, the facility took a central hub role, creating previs and postvis, co-ordinating the shops and handling asset sharing. Method Studios took on the duties of lead vendor and began a major asset building program for key buildings and Washington D.C. surrounds based on plates shot and photographic and online reference.
"One thing that's quite interesting about the White House is how much it changes over the years," says Method visual effects supervisor Ollie Rankin. "Each President and First Lady stamp a little bit of their own on the White House and the grounds. There's a vegetable garden there now that Michelle Obama instituted. So we had to balance a few things. They did shoot some plate photography for other sequences involving the limo chase. So we made our grounds match as close as we could to that."
Method mapped out the grounds with surrounding buildings and ensured prominent trees were featured, too. "We matched 10 to 15 trees in reality and then others we matched in terms of size and shape," says Rankin. "We used SpeedTree for building most of our trees. That also allowed us to put some movement in the branches. Even when there is no helicopter hovering over, they still need to move, and then move even more when there was a chopper."
Method also built a deep distant cyclorama - full 360 degree coverage of all the distant buildings. "Then we started working our way inwards in matte paintings, putting things on cards for parallax," notes Rankin. "Then the 3D guys were working outwards from the White House building higher resolution detail as far back as we needed it working in Maya and V-Ray."
One new approach Method took was to complete many of its own shots using NUKE's 3d capabilities. "We would always have our 3D environment represented in NUKE," says Rankin. "The distant cyclorama background, the monument and trees and buildings in the middle-distance all on individual cards so we could load the matchmove camera into NUKE. We could load the 3D camera in NUKE and run out a background inside of NUKE without having to go through CG's hands at all. That's an invaluable thing and I think more set extension work will happen entirely in NUKE."
Another 'first' was Method's major adoption of MARI for texturing. "You have hundreds of objects that have the same material type but need to have their own texture space," explains Rankin. "We used the UDIM model of texture allocation. It's a way of expanding the normal UV texture space into multiple UV texture co-ordinate systems. So rather than having to fit all of the textures into one zero to one square, you can have a unique square in virtual UV texture space for each of the objects. And when you assign a texture to a group of objects you can do it with a wildcard."
"So instead of having to say each of these 1000s of components that make up the White House," continues Rankin, "each one of them doesn't need to have its individual texture assigned, because it knows the whereabouts in that UV texture partition to look. It uses a file naming convention where there's a ID in the file name that tells the shader which part of the UV space it's looking at."
This method allowed artists to 'genericise' the materials and shaders much more than normal. "The shaders of the White House were actually a very interesting challenge," says Rankin. "We used to joke with our clients that there's an entire division of the Pentagon devoted to developing paint for the White House - it has this quite unnatural way of responding to light. In photos it looks a little bit fake - it's super-white and it has this property that even in the crevices and grooves and underhangs, it doesn't get strong shadows - the light bounces around and fills them in, it seems. It's also so, so white that it picks up a lot of color from the sky and grass and trees around it."
Rankin is proud of the detailed work in realizing the Washington assets. "There's one shot we had where a guy was shot on bluescreen - he's 100 pixels high in the frame standing on the balcony of the fully CG White House and the curtain billows out the door behind him, as a helicopter hovers down behind him rustling the leaves of the trees. I don't think most people will really appreciate how much work went into that."
Action scene #1: The dawn fly-over
The action: In the early morning, three Marine One helicopters fly over Washington and the President decides to do a detour and fly over the Washington Monument, the Lincoln Memorial, Elipse Park and Washinton Memorial Park.See some of LUXX's shots in the film's trailer.
How they did it: LUXX Studios created Washington icons and the helicopters for the five minute sequence, based on an initial previs. "The main difficulty for us is that we needed to show the everyday reality without any disturbance, no explosions or fire," explains LUXX visual effects supervisor Christian Haas, who oversaw the work with Andrea Block. "We simulated the fountains in front of the White House, the interaction of trees and grass when the helicopters fly by, water ripples and foam when the marine one helicopters fly over the reflection pool and stir up fall leaves."
3D lead Alexander Hupperich worked in 3ds Max to create the Mall, adjacent museums and other buildings. Compositing supervisor Max Stummer established a pipeline for up to 86 V-Ray elements and extra passes and allowed for adjustable heat ripples in the space around the helicopters. "For the city background we used digital matte paintings with NUKE in 2.5 D projections and 360 degree HDRI morning skies," says Haas."
The Marine Ones were modeled in 3ds Max by Dennis Müller. "He started with a simple box and added details by details," explains Haas. "The production looked very closely to this model, because we had to share it with other vendors and we had some shots were it was cut direct to shots with the set helicopter. The model itself had around 1.5 million polygons. Every rivet was there, at some point we had to remove some details from our model because the set helicopter did not have these elements."
The fountain in front of the White House was completed as a RealFlow water simulation. "When the Marine One approached the reflecting pool we added water spray completed with FumeFX and simple water simulations for the interaction with the helicopters," says Haas. "We used a mix of RealFlow and simple Fume simulations to generate different masks to shade the water with displacement ripples."
"For the approach to the White House we generated hero trees with GrowFX," adds Haas. "The developer added a feature for us with gave us the possibility to control the wind effects much better, this way the trees and branches could bend very realistically. For the closer shots we added V-Ray fur controlled by procedural maps to get the waves in the grass from the rotor."
Action scene #2: The Capital Building explodes
The action: One of the terrorists wheels a cleaning cart into the Capital Building and triggers a bomb, causing an explosion.
How they did it: Method Studios created the bomb blast and surrounding environment. In a signature shot, the camera sweeps around the Capital Building's prominent dome as three layers of windows blow out and then becomes a churning cloud of smoke.
Method realized shots of digi-doubles being blown up with an incredible fireball, as well as the dome explosion - completed with Maya and Houdini. "We had a beautiful plate to work with," explains Method Studios visual effects supervisor. "But the Capital Building was originally built in Lincoln's time, so in that way it doesn't really meet the exacting standards of CG modeling. It's very difficult to line up exactly where the windows are. In the end we found it was better to completely replace the dome with our CG dome - so we could get the windows and fire and glass existing in exactly the same space."
Action scene #3: The limo chase
The action: Cale and the President are chased by the terrorists in the Presidential limousine - the Beast - around the White House gardens before flipping into the pool.Watch part of the limo chase in this video.
How they did it: Prime Focus orchestrated shots of the chase while ScanlineVFX delivered the digital splash shot.
The limo chase was filmed at a park in Montreal next to the Olympic stadium. "The park used to be a golf course, and still looks a bit like it," admits Marc Weigert, "so we had to work out which directions we could shoot and whether we needed to use bluescreen or rotoscope. And one of the first things we noticed was that Montreal is a pretty rainy city. Even if we had a beautiful sunny shooting day, it usually rained the night before. So in the morning everything is still wet, so the cars had to drive at a crawling pace. So we tried to shoot with long lenses and work out ways to make it faster."
Prime Focus received White House and grounds assets from Method Studios. "The rest was built by us," says Prime Focus visual effects supervisor Alex Pejic, "including the Beast, SUVs, terrorist vehicles, tanks, digi-doubles, crowds, humvees and other military vehicles. We also plugged Method's trees into Houdini for dynamics."
The studio built a CG limo from photographic reference and then also added in extra damage to the live-action version from near-misses and the gun and RPG battle that ensues. Several explosions were filmed live-action while some were augmented or fully CG. "The pool house explosion was a full digital shot," notes Pejic. "We used Houdini for fx work and destruction, rendering in Mantra. Then the rest of the environment - the White House, trees et cetera - was rendered in Arnold."
Prime Focus compositing supervisor David Shere notes that the studio has only recently moved to Arnold, but with impressive results. "The beauty passes are gorgeous," he says. "You get a great starting point from CG. The only disadvantage is that you get a little less control than compers are used to having. The diffuse and ambient passes are merged into one, so we've had to think about shots differently."
Significant comp work was required for bluescreen limo shots and adding in Washington backgrounds for scenes filmed at the Montreal park. "We'd enhance reflections in the windows, play up anything in the plate that could give us some atmosphere or anything that was between the foreground subject and the backplate, like the glass plate or smoke, debris and dust," says Shere.
Scanline worked on shots of the Beast being hit by an RPG missile and catapulting into the White House pool. "Those shots were full CG, with Flowline water. The environment is also full CG, with references from outside shooting and the pool shot from the studio," says Scanline VFX supe Jan Krupp.See the limo splash.
"The car also jumps through some trees, so we had simulated those," adds Krupp. "Those trees had a hierarchy we could access in Thinking Particles, and decide which parts get ripped off or bend to the car. It also triggered a sim of leaves flying towards the camera."
Action scene #4: Washington fly-throughs
The action: Three Blackhawk helicopters fly low between Washington's buildings in an effort to remain undetected.
How they did it: Hybride created the sequence over 45 shots, including nine full digital scenes. The studio followed a provided previs clip, modifying it to match the width of the streets and the city environments. "We also studied footage of real choppers flying at low altitude over cities," says Hybride's director of R&D Mathieu Leclaire. "Helicopters landing in a city park were used to recreate the down draft effects on the surrounding trees. We also studied how the light in early morning bounces and is reflected on the different types of buildings. It was important for Roland Emmerich to carry a sense of early morning light and shadows on a perfect autumn day."
To create city blocks, Hybride drew upon a city building tool originally developed for Spy Kids 4. Here, the buildings had been realized as instances with windows, walls, doors et cetera using Softimage ICE. "The challenge in White House Down," notes Leclaire, "was that we needed to recognize every specific landmarks from Washington D.C. with the helicopters flying between the buildings, we needed a lot more detail on the street level and we needed to get a lot of interaction from the helicopters rotorwash."
Hybride therefore updated its props and cars distribution systems, which were still ICE-based instances but now had more controls for higher complexity. "Everything was also converted to Stan-Ins to keep our working scenes very light and leave the heavy lifting to the renderer," says Leclaire. "We also updated our renderer to Arnold. Arnold is very powerful and can manage incredible amount of geometry while keeping the render time very reasonable."
"We built a deep image compositing pipeline for this project as well," adds Leclaire. "This new pipeline allowed us to manage even more geometry in our scenes (we calculated over 4.2 billion polygons for one specific shot). We started out using NUKE to manipulate our deep images, but we ended up creating an in-house custom standalone application to accelerate the deep image manipulations." That was completed with Creation Platform from Fabric Engine.
Modeling and texturing of assets such as fire hydrants, manhole covers, street signs, buses, vegetation and other city decal was carried out based on real photographic reference. "For texturing the generic assets," explains Hybride visual effects supervisor Philippe Théroux, "we used a system based on rules driven by color-coding. With this system, we quickly created shading networks for all the cars and miscellaneous elements of the city. Our crowd system was also populated with hi-res models."
Théroux suggests that the small details helped sell the synthetic shots. "For example, the glass buildings reflecting light on the older stone building, and the myriad of details helped make the city look real. Since there are many trees lining up the streets in Washington, It was also important to nail the animation of the branches and foliage. Rotor wash interaction with the autumn leafs, dust and debris helped sell the power and speed of these low flying helicopters in the heart of Washington."
Action scene #5: Crash of the Black Hawks
The action: Three Black Hawks reach the White House but are, in turn, shot down by the terrorists.Watch part of the crash sequence in this video.
How they did it: Method Studios took on initial previs to further refine the actions for the three crashes, in addition to combining some gimbal-filmed shots and repelling soldiers shot on bluescreen.
The helicopters were modeled in Maya and textured in MARI. "Rivets are right on the cusp of that effort," says Rankin. "If you put them into the model, they're going to give you really nice lighting characteristics. As the light angle changes on the rivets, they pick up nice highlights. But it also makes for incredibly inefficient rendering. In this case we chose to leave the rivets in the textures, and only had to do some extra work for a few shots."
For the first crash, which sees a Black Hawk hit the ground, have its rotor blades tear into the ground and then wrap itself around a tree, Method looked to online reference. "It turns out they actually tend to go down gently from the air resistance of the rotors," states Rankin. "But for the first two impacts Roland wanted to make sure they were fatal impacts, but in a PG-13 way."
The destruction of the choppers was achieved by modeling clean and broken elements. "It was going to be one frame intact to next frame broken for any given component of the helicopter," explains Rankin. "So we modeled the rotors intact and broken. The fuselage we would model intact and then model the various dents and crumple zones. Then it was more of a challenge for the rigging to model the progressive damage. So rather than allowing the damage to take place, the animators were given the controls to switch components of the fuselage from clean to damaged, progressively over the course of a shot."
"For the ground being churned up," adds Rankin, "we sim'd in Maya but took that out as an Alembic cache, brought it into Houdini, sprouted grass on it and gave it thickness and dirt texture with pebbles and roots."
The second crash has a Black Hawk ending up in the White House fountain. "One of our Houdini TDs created the water sim," says Rankin. "One of the things you see with a rotor spinning so fast, you don't really read the water being kicked up individual and circulations of the rotor - it's more like a huge sheet of water that comes flying up. So when we ran sims of the water using actual animations of the helicopter, it produced almost ugly results. So we found using an older version of the helicopter animation with less accurate geometry caching representation was the best input to use for the believable splash. The hardest part of simulating the water, was getting the fountain in its normal state - the jet of water! - which we did with real footage of the jet on a card."
The third crash segued Method's digital work into live action, which meant the studio had to match a helicopter carcass filmed on set. "Whatever our helicopter did it had to end up in that final resting place," says Rankin. "Production also liked the idea of the rotors gouging out chunks of pillars from the portico. They had built that into the set, so we had to make that part of our crash sequence."
Rankin notes that adopting a deep compositing pipeline in NUKE was crucial for some of the heavy Black Hawk crash shots. "There were so many layers of dirt, smoke, fire explosions. We were rendering in multiple packages and updating sims. If there were say 150 layers in that shot, there were 1500 render passes that went to producing the final comp. Actually there were so many layers we found it wasn't feasible to have it 'live' in the NUKE comp, so each night we would run the deeps in a pre-comp to build all of the layering into it. Once that had run, it was just a traditional multi-layered 2D comp being run."
Action scene #6: Air Force One goes down
The action: A missile hits Air Force One causing it to start breaking apart as it dives and then tumbles through the clouds.Watch a breakdown of Scanline's work for the Air Force One sequence.
How they did it: Scanline VFX created the Air Force One shots completely digitally, relying on their incredible simulation skills and proprietary Flowline software.
"We started with the previs and worked out what would be a dramatic shot," explains Scanline visual effects supervisor Jan Krupp. "Then when we had the animation locked in, we worked on lighting concepts."
The studio had an existing model of the Presidential plane built for Emmerich's 2012, but this new film required closer shots as well as some refinements to extra additions that had been made since to the real aircraft. "We had to detail out extra things like the gears and new adjustments for the top of the plane," says Krupp. V-Ray was used for final rendering of the plane, with some refinements made in compositing to give Air Force its distinctive finish.
The plane lurches sideways before heading through the cloud bank, but Scanline had to ensure it maintained a strong sense of weight in the animation. "Everything that gives it the drama is the camera move," notes Krupp. "There is some detailed animation on the wings and engines that shake a little when it blows up, but we kept the plane slow and heavy looking."
For destruction work on the hull and wings, Scanline blocked out breakages on a rough model, then refined a 'destructive' model with detailed animation of pieces and debris flying off, including views for the internal parts of Air Force One that were now visible.See the final sequence.
Simulation-wise, Krupp explains that "the basic approach was to rig the plane classically with blend shapes and deformers and then feed parts of that into Thinking Particles and give all this deformation of the geometry to Flowline." Simulations for fire and smoke were split up to give compositors the ability to relight or control lighting if necessary.
The clouds themselves were also completed in Flowline as simulated volumetric shapes allowing Air Force One to 'dive' into them. And Scanline added in extra details to the shot where required, too, including the flares that one of the F-18s sends out, plus another jet being consumed by smoke spewing from Air Force One. The result was a deep and complex scene that came together thanks to visual effects. "It was so incredibly beautiful that each time we watched it we discovered something new," comments Volker Engel.
All images and clips copyright 2013 Sony Pictures.
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