Half-way through Edgar Wright's The World's End - and consider this your spoiler alert - the film changes tact from pub-crawl buddy comedy to a full-on alien invasion and survival story. The twist is revealed in a close-quarters bathroom brawl in which most of the townsfolk of Newtown Haven turn out to be robots.
That bathroom scene features decapitations, flying arms and limbs and blue gloop - effects that might have been normally achieved with 3D animation. But, since The World's End was crafted with a relatively low budget - around $20 million - the effects teams had to bring to life the robot fights, and other effects in the film, through other means.
Enter Double Negative and visual effects supervisor Frazer Churchill. Having worked with Wright previously on Scott Pilgrim vs The World, Churchill knew that the director "loved visual effects, but also loved the art of stagecraft." The Dneg supe therefore suggested that to keep the effects budget manageable, they would have to mix significant prosthetic and animatronics work with digital compositing.
Above: watch a behind the scenes breakdown of the VFX.
"For instance," says Churchill, "we've got these robots that have their heads pulled off and underneath they're like action figures with an action figure-style peg.
"So I thought if we've got to do 3D renders every time we see that it's going to be beyond the budget. Nuke has really matured into a tool that has such good 3D capabilities within a 2D environment - so we went with that approach."
That didn't mean The World's End was devoid of 3D or effects animation. Certain shots, including a statue that comes alive and a final plasma wave and explosions, were also required and made use of Dneg's experienced artists and VFX pipeline.
But other effects like the decapitations or the glowing mouths and eyes of the robots were shots that were either fully practical or used physical elements to inform digital augmentations. Dneg's senior compositing team, made up of Steve Tizzard, Trevor Young and Luke Letkey, tackled these tasks.
Arms, legs and heads
Prosthetic designer Waldo Mason and animatronics effects supervisor Matt Denton combined to deliver practical pieces used in the robot fights.
"Wherever there was a limb that needed to come off or an object that needed to be created as a semi-CG item," explains Churchill," Waldo would make us the neck piece or arm piece and the pegs that are revealed. After each take our effects coordinator Jack Hughes had one of the physical objects on a stick and we would hold it in the position and Jack would move it through what would become the movement of the character."
"If we got lucky we'd use that 2D element in the comp," adds Churchill, "and if not, at the very least, we'd re-project it and have CG approach."
Dneg 2D supervisor Graham Page established a pipeline for essentially a single artist to be responsible for a single shot by manipulating these semi-3D objects in Nuke and handling matchmove, re-projections, lighting and rendering.
This extended to shots in which the human-looking, but robot, heads were smashed - another mix of practical and digital work. "In order to create the smashing head effect," explains Churchill, "we knew we wanted to create a composited element solution as fx-animation was outside our budget range for the number of shots it involved. Waldo cast the performers' heads and made wax heads filled with blue gloop. He then chilled them in the fridge to make them nice and brittle and we mounted them on c-stands and smashed them with an iron bar against green. Creating this effect was a lot of fun."
The blue gloop that spills and splatters from the robots was also a practical concoction developed by Mason for use on set. "Where someone was decapitated we made sure we flicked it around the set and we'd shoot that as an additional pass," says Churchill, "or we'd shoot the gloop itself out of a pipe at 48 frames per second."
A fully CG head overseen by CG supervisor Joel Green was constructed for Martin Freeman's character, Oliver, who is revealed as a new robot when half of his scalp is torn off. "Even then," notes Churchill, "I got Waldo to make Martin Freeman's broken head from a cast, and made a completely blue inside piece. Waldo mounted one of those heads on a stick for us and we would go in and whenever that character was appearing, Jack would run that through in front of camera and that was our invaluable reference for lookdev and lighting."
Eyes and mouths
The full extent of the robots' existence is revealed when hoards of the synthespians chase the main characters through the town and display a glowing mechanical blue light from their eyes and mouths. Like the robot limbs, that glowing effect also had a practical origin.
"Edgar is obsessed with this Bonny Tyler clip called Total Eclipse of the Heart from the 1980s where all the kids have got glowing eyes," recounts Churchill. They used googles with lights in them to do that and we took the same approach."
Matt Denton engineered goggles for background characters to wear on set complete with bright LEDs that would provide a 'classic' anamorphic lens flare (the film was shot on film by Bill Pope, ASC with 'B' series anamorphic lenses).
Dneg removed evidence of the goggles for these characters, while the glows emanating from foreground actors' eyes were done via compositing.
That's the same approach we wanted to use. Matt Denton, the animatronics guy, engineered these goggles which the stuntmen wore with bright LEDs in them and you get these classic anamorphic lens flares. "Having the on-set reference and then shooting the glows on black as elements to overlay on top was invaluable," says Churchill."
"We did a similar thing with the mouth glows," he adds. "Matt made these boxing mouth guards and put an LED light in them, so the characters are wearing LED mouth guards. It lit their mouths and backlit their teeth. We'd just go in there and erase part of the mouth guard so you could see the tongue through it."
Amidst the pub-crawl and robot encounters, the main characters eventually reach The World's End - the last drinking hole on their quest. But here they find a hidden chamber and an alien, voiced by Bill Nighy, represented as beams of light.
Again, practical means were employed to help establish the look of the effect. "That was a tricky effect actually," recalls Churchill, "because we had these beams of light that had a personality. The location was a water pumping station in east London and the idea was to set up this LED light board so when they play Bill's pre-recorded dialogue the lights would pulse in time and everything in the environment would have interactive lighting on it."
The interactive lighting served as a basis for the final shots by Dneg, which altered the beams and glows based on Nighy's delivery (which was further refined after principal photography). "It would change shapes when it was angry or more meek," says Churchill. "It was a Nuke solution, the particles fooxy in there were Nuke generated. The information graphic doc that spins around is Photoshop and Nuke - done by Oscar Wright, Edgar's brother, and we generated some elements too."
Ending The World's End
After turning down the alien's suggestion that they acquiesce and become robots, the main characters escape The World's End as the town of Newton Haven begins to self-destruct.
The pub on location itself was filmed with pyrotechnics and fireworks that Dneg augmented with glows and effects animation. As the heroes drive away they are then engulfed by a plasma wave. "Edgar had always imagined a chase where we would be seeing the British countryside devoured by a fireball and seeing the classic patchwork quilt of British hedges going up like dominoes," says Churchill."
"So in order to have the car feel like it was being engulfed in flames, we would build flaming wall exteriors and drive the car through it. Chris Reynolds, the SFX supervisor, put down 150 gas canisters and run them through chicken wire and we had stunt drivers going through walls of flame - shot via a helicopter and a low angle tracking vehicle."
Dneg completed the shots with background matte paintings and further effects animation. The escape builds up to blanket destruction of the town and, ultimately, much of the Earth. For the look of roaring fires, Churchill again referenced real-world scenarios. "I remember seeing these storms when I was in redtube Spain. You'd look out to sea and see these balls of lightning that would go in all directions. I had these ideas about multi-colored lightning and was also looking at pics of volcanoes with pyroclastic cloud plumes that seem to generate lightning. It was almost Biblically apocalyptic."
Perhaps encapsulating Double Negative's overall approach to the visual effects of The World's End is one shot of a Newtown Haven map that comes out of one character's pocket and falls onto the camera lens.
"In a big summer film we'd probably have done that with 3D," admits Churchill, "but on this film we basically pulled the map out of the pocket with fishing wire and then I was just holding it there and rolling it over towards camera, basically hand-manipulating it towards the lens so we could comp the pieces together."
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