Stitch by Stitch: MPC talks about “1917”
Creating invisible visual effects was not an easy task for MPC especially when having to place them within one continuous shot for World War I drama “1917”…
Recalling the stories told by his grandfather about being a soldier during World War I, filmmaker Sam Mendes co-wrote a script chronicling the real-time journey of British Lance Corporals Thomas Blake (Dean-Charles Chapman) and William Schofield (George MacKay) through the war-torn French countryside to prevent an attack which will result in a massive slaughter by the Germans. Unlike his previous war film Jarhead, Mendes decided that the best way to immerse the audience was to create the cinematic illusion of one continuous shot with the camera never leaving Blake and Schofield. The concept complicated the visual effects process supervised by Guillaume Rocheron (Ghost in the Shell) and for sole vendor MPC as the work could not be divided into shots; instead preciously rehearsed and timed takes needed to be stitched together.
Preciously rehearsed and timed takes needed to be stitched together.
“There were certain things that we knew going into it like finding ways to stitch the connections of the different takes,” states MPC VFX Supervisor Greg Butler. “We would assess each one and ask, ‘Is there a 2D approach? Does it require 3D? Is it a hybrid?’ We would break down each of these moments and figure out the best approach. But as much as we knew it would be a different way of working, throughout we would find new things that we hadn’t thought of.”
For the most part scenes were shot chronologically. “It helps everybody, especially in a situation where there’s no going back.” The extensive exterior locations meant that there had to be some sky replacements, grading and bouncing; there was also the matter of enlarging artillery craters and dealing with a massive muddy environment. Like with any movie you almost never have the first take, so by the time you’ve got the take you’re going to use, and in this movie it could have been the 20th take, the ground has been gone over multiple times. There were situations where we had to replace the grass or mud to remove evidence of the previous takes.”
No Man’s Land
“We did a lot of addition and extension to No Man’s Land, more for design reasons because as Sam watched the shots, he felt what they had on set wasn’t quite enough visually of the bombed-out craters and the water pooling in them,” remarks Butler. “I was worried about getting the right wet sticky look to the mud, but it turned out okay.”
“We had a really good environments supervisor who had gotten to walk through No Man’s Land and also had good data acquisition. Once we came up with our scattered crumbly mud bits it could be laid in where needed. There were a couple of times where we increased the water level in some close-up craters as they walk by to make them look much more dangerous.”
Huge black rats were entirely CG. “We had very few assets that you notice in the movie like the rats and planes,” reveals Butler. “The rats were the most intense in terms of design because Sam wanted a specific look, especially for the ones inside of the German bunker that you first see. He wanted them to be like king of the hill survivors that were big, fierce, nasty, and stealthy. We had to work a lot on the groom to get it to look mangy and matted. Coming up with the right black level and greasiness was very iterative. In the end, the asset itself did most of the work.”
“Compositing had to balance the level of greasiness and the black levels because in that dark environment there wasn’t much range to play with by the time we were done.” Rats appear in the trenches. “We started with our hero rat, and began making variations of size and color, so in total there were five different rats. But then as we started to use them the fur variation worked against us because in parts of the world rats are monolithic, and the only difference are their weight and whether they have scabs and wounds. In the end, we made them much more similar.”
The rats were the most intense in terms of design because Sam wanted a specific look, especially for the ones inside of the German bunker that you first see.
An aerial dogfight takes place with the shot down German biplane crashing towards Blake and Schofield. “We built a Sopwith Camel that flies over Blake and Schofield as well as a detailed German Albatros D.III plane which had to match up with the one that they had onset,” explains Butler. “That handoff was fascinating. I’ve done digital doubles and prop handoffs before but not in this way where a CG plane flies towards you; explosions happen, and reveals the practical one that was taken from a later plate.”
“The A-side had the actors running and diving to avoid something that was not there. They hadn’t shot the special effects plane yet, or the aftermath. It was because of logistics and strategic planning. For a lot of the stitches you had to either bring in the B-side to the A-side, or vice versa. Given that we would have to see the close-up plane burning in the later shots more, until that was shot we didn’t know what it looked like in the A-side.”
There are minimal virtual moments. “The only time we touched any camera movement was for stabilization or recomposing based on editorial input,” reveals Butler. “The camera crew, the actors and the AD got very good at repeating performances, so by the time we would get the two takes it was done as well as it could have been without resorting to motion control. Motion control would have been impossible. Everything had to be self-contained and move through the world like the Steadicam footage.”
The different departments had to work in a cut independent way. “We had two compositors sitting next to each other. One was in charge of the shot of the plane crashing and the other was responsible for the moment afterwards where the camera keeps going, and Blake and Schofield get up to save the pilot. Effects would provide them with a continuous simulation of dust and debris that covered the whole moment, but it would be delivered in two frame ranges. One shot couldn’t finish until both of them had finished. Every time one compositor added a little patch of fire to enhance the shot it had to be in the other compositor’s shot.” Automation was not possible as each shot was different. They shared an approach to the work in Nuke and kept bouncing the work back and forth until one of them finished, and then the other compositor could complete their shot.”
“Just as hard as the stitches themselves were the internal invisible stitches which were shot continuously,” notes Butler. “We would get a 3000 frame continuous take with no stitching required but visual effects pipelines are not used to, or good working at 1000 frames at once; we would break it up into 600 frame chunks to distribute them out to different artists, but they would all have to connect seamlessly together.” Shots could not be worked in parallel. What we didn’t expect going into it was how even the easy shots could be incredibly painful because of the domino effect. You could have somebody adding a simple dust element in the background of a shot, but that immediately affects the next shot because it has to be the exact same thing.”
Various camera rigs need to be stabilized and integrated to create the impression of a flowing shot. “Some of the camera rigs would have a different rhythm to them,” remarks Butler. “You would have to soften going out of one shot so that it didn’t bump when you get into the next one where the rig had a slightly different vibration to it. An interesting one was when Schofield swims behind a rock you see him come out the other side and his swimming stroke was a half stroke off. There were subtle things like that all over the place. Editorial was good at doing those things with adjusted retimes which we would have to implement. The amount of invisible retime in the movie is also significant because that was one of the only tools that editorial had to influence the pace and rhythm and occasionally fix things in the movie, because it’s not like they could add or delete a shot.”
“The visual effects/editorial relationship is usually significant because we depend on each other to fix, improve, and embellish,” notes Butler. “On this show a lot of the tools on both sides had been taken away which meant that we talked much more about retimes and reposes instead of takes or cuts. It was rare that we had a change in-take for any reason because if you change the take then you alter the connection and it doesn’t work.”
At the end of every day of principal photography a hero take was selected in order to start the next day of shooting. “That’s not a decision that usually has to happen until post-production. The short schedule on this movie was ambitious considering we were taking on a way of working that has almost never been done with significant visual effects. One of the things that even made that possible was that the director’s cut was happening as they shot. When it came to the actual director’s cut that followed the shoot a lot of what happened, there was tweaking of retimes and things that didn’t affect the cut.”
Blake and Schofield enter a farmhouse. “It was a tricky moment,” admits Butler. “There was no obvious foreground wiping. Anytime you’re trying to do the illusion of a single take, foreground wiping are the easiest tools available but they were used sparingly in this movie. Even some of the foreground lights that do exist were not full-frame. In the case of going in and out of the farmhouse it’s hidden blending. Most of the environment work in that whole landscape was the addition of smoke plumes to show that the Germans had left behind destruction. We also added dead cows and did a lot of greens and set dressing work.” Trees, bushes, roads, and non-period elements were painted out. “We took even more away because Sam wanted the environment to look stark.”
For the scenes that take place in the destroyed French town of Écoust-Saint-Mein, magnesium flares were fired into the night sky that travelled 130 feet and lasted 22 seconds. “It helped that we didn’t have a lot of digital extensions to do. The set was 80 percent complete,” observes Butler. “For the buildings that were digitally added all we needed to do was use the light timings of the nearby buildings and key off of them. When Schofield first enters the town the shadow moment did make it extra tricky because we had to hide a blend in there somewhere.
Having things go dark is helpful but we did have a rule that it could never go black. Other than when Schofield goes unconscious there is never time when the frame goes black and you can’t see something. There were composition reasons and we never wanted to the audience to feel that we had cheated. We always had to continue something through transition that would guide your eye and make you believe that you weren’t being tricked.”
Schofield jumps into river while being pursued by German soldiers and encounters a waterfall. “The waterfall was one of our hardest moments in the movie,” reveals Butler. “It ended up being a combination of digital double, plate elements of the actor, some digital water simulation and projected water elements from mostly the A-side. It was filmed at a canoe training facility and on a real river. We did extend it to get a much more dramatic waterfall, and tried to use that as a bridging element, but everyone agreed that the waterfall was so out of scale with the river that it didn’t look like Schofield would have survived. It’s not meant to be a huge river or a 100-foot drop, but it still needed to appear dangerous. We backed off and came up with one that had a 45-foot drop.”
In order to deliver his urgent message to call off the military attack, Schofield shortcuts through an active battlefield. “The biggest thing we did was hide all of the special effects equipment, crew, and unintended aftermath,” states Butler. “It was important to Sam that unlike the early trenches in the movie which were muddy and had been lived in for months, these were fresh ones of white chalk. Nothing has happened yet. I’ve never seen that before. It was critical when the soldiers first run out of the trench that they’re walking on fresh green grass.”
“The minute the first rehearsal was shot, the grass started to get matted down and special effects had to do four pits in the ground for every one explosion. There were over 26 pits dug in the ground that we had to hide and disguised as they were revealed on separate takes.” George MacKay, who portrays Schofield, got knocked over a couple of times unintentionally but kept on. Everybody knew that they had a maximum of four takes and there was no going back. I don’t know what take they ended up using but the fact that he gets knocked down, gets up again and catches up with the camera in an organic way was amazing.”
Supporting the one-shot nature of the project was the biggest challenge. “There’s a moment where Blake and Schofield are about to enter No Man’s Land and the stitch had to take place directly on the actors,” recalls Butler. “It was a rare case where the two sections shouldn’t be joined. Most of the time the shooting was so good that we had to manipulate but didn’t have to create new footage to connect. This is like the waterfall where the middle connection point didn’t fit so we had to create it.” Brief and critical digital doubles make an appearance, in particular of Schofield. “The mud on the costume and the hair style had to match the actor.”
“I like the final run along the trenches because after being immersed in the movie for that long he’s finally going for it and you know he’s either going to succeed or fail the mission,” remarks Butler. “Having the explosions, sound and music, the intensity of the payoff at that moment is the most gratifying especially because without our work it would be like a guy running through a special effects minefield. This is the best example in my career of invisible visual effects work that is designed to support a bunch of other departments. It’s the highest level of work that I’ve ever seen. I almost prefer not to talk about it but if we don’t people will never know the work that we put into it. It is gratifying and nerve-wracking to never see visual effects mentioned in any movie reviews. Normally I’m glad because if we’re ever talked about it is because we did something wrong. The movie comes first. It shouldn’t be about the visual effects.”