Combining science fiction, romance, horror and action, Apple Original Films and Skydance Media’s The Gorge tells the story of two snipers from Eastern and Western Block countries posted as sentries on either side of a huge, deep gorge, who are drawn to each other while preventing mysterious beings from escaping the hellish environment beneath them.  For the creature feature, filmmaker Scott Derrickson partnered with Visual Effects Supervisor Erik Norby, who recruited DNEG to handle 750 shots across 18 sequences of the action that happens above and around the edges of the gorge. Given the title of the movie, the environment had to be treated as a principal cast member. “There was a little bit of pressure because we obviously knew that the gorge would feature in a lot of shots,” states Anelia Asparuhova, VFX Supervisor, DNEG. “And also, we knew that the gorge is one of the characters. We wanted to make it as realistic as possible. We even hired a geologist for the first few weeks of building the gorge because none of us were a specialist. You can look at many pictures, but it always helps when you have someone who has studied gorges to tell you, ‘These rocks are fine. Don’t put those trees there.’  It was invaluable input.”   Scans taken of Norwegian gorges were used as a base. “It never becomes clear the exact location of the gorge,” remarks Asparuhova. “We reasoned that it should be in Europe for the Eastern counterparts to have enough interest to protect themselves.”  A large vegetation library was created. “Coniferous trees stay green and in order to convey the different seasons, which is a big thing in the movie, we scattered some deciduous trees here and there,” says Asparuhova. “We wanted to make sure that we weren’t looking at the same trees even though our library of trees was probably bigger in terms of the variations.  We wanted to make sure that types of trees being chose were specific to the Northern and Central Europe regions.”  Close-up chase shots used actual plate photography captured in a forest, at which point, “We noticed that even more species would have to be added to the library to match closely to trees that were shot because we had to extend forests behind plates to look photorealistic,” notes Sebastian von Overheidt, VFX Supervisor, DNEG.   “Shots with plate forests would cut to full CG forest shots and back and forth. We had some reference from various locations that added to the complication.”           Much of the film is set within and around two prominent cement sentry towers situated on either side of the gorge directly across from one another. “The tops of the towers were done on a stage, and the DP did a good job with the lighting and made our life easier,” Asparuhova says. “The bases of the towers were actually built outside.” The middle sections of the towers were entirely CG. “There is a short conversation when Levi [Miles Teller] is alone on the radio with Bartholomew that was planned as a reshoot to get the dialogue right,” remarks von Overheidt. “For those shots, we had to create a full CG interior, but it was out of focus, so it wasn’t too detailed.”  Certain landmarks served as visual cues for the audience members to understand where the action was taking place. “A big part of our blocking process to make sure that it’s easy to follow where we are,” explains von Overheidt. “There are a couple of landmarks, like a helicopter landing platform on Levi’s tower side, or a gate that you see in a couple of great moments. But other than that, in some camera angles we would cheat the tower into a certain position for a little bit.”  The forests assisted with the directional orientation. “We did put more deciduous trees on Drasa’s [Anya Taylor-Joy] side,” reveals Asparuhova. “Partially because it was allowed by our geologist.”  Obscuring much of the gorge is a poisonous fog. “The fog is semitransparent so if you go too shallow [with the gorge] then you run into the danger of seeing edges,” states Asparuhova. “We did do a few rounds to figure out the amount of detail we wanted to see in the fog in order to have some movement. It’s all subtle. It’s the same with the movement in the trees. Your eye doesn’t catch the movement as you look at the shots but without it the trees would look like a painting. That’s why we wanted to add a little bit of motion and character in everything.”  Wind also helped contribute to the believability factor. “We spent time to find the right amount of movement in the trees and vegetation, especially for closer shots where there’s dialogue, and on their towers,” von Overheidt says. “Even if the background is completely out of focus you never want to settle on a completely static frozen image. You always want some shimmering and movement going on in the leaves.”  That movement varied depending upon the scene. “We have these sequences where it’s raining, or Levi gets woken up by the wind slamming the door,” Asparuhova says. “We wanted to have heavy motion in the trees during the storms.” A lingering mist among the trees helped convey size and scale. “That gave a sense of vistas and dipping a horizon into a bit of mist helped with the depth,” adds Asparuhova. Lighting plays a major role in getting the proper scope for shots. “In general, one thing that helps with creating environments at DNEG is that we’re able to render realistic depth cueing that respects lighting,” observes von Overheidt. “It changes with sun directions and where shadows fall. This is an actual render component of our beauty layer that fits on top. That makes a huge difference for large scale environments to already setup the right scale.”   Atmospherics were used in certain circumstances to increase the realism. “When Levi goes over the gorge on the zipline, we added some wispy clouds passing by to underline the sense of speed,” states von Overheidt. “If I remember correctly Levi was a plate element in all of those shots. They shot from various angles, and we would go further out but always keep him as he goes over the zipline. We would replace the zipline itself and maybe the harness and connection line. The way Levi performed onset his full weight was hanging off a wire. It looked realistic.”  Digital doubles were created for the characters of Levi and Drasa. “When Drasa jumps off of the platform to go into the gorge after Levi and pulls the parachute, that was a digital double takeover,” von Overheidt reveals. “She jumped off the platform for real and landed on a crashmat. During that takeover, when she’s jumping, that’s where we had to precisely lock in with her performance by body tracking her and making sure that folds, creases, the position of the backpack and hair lined up as accurately as possible. Then there are 10 to 15 frames of transition that needs to be locked in and taken over with an animation performance that is all CG.”    Vehicles like helicopters were scanned while the art department provided models of the drone and quadcopter. “We made the quadcopter and drone more worn,” notes Asparuhova. “The drone had to be something that had been down in the gorge for a long time. We wanted to make sure that was clear.”  An actual drone prop flew through the forest and crashed. “We used the prop as a reference but beefed it up quite a bit,” remarks von Overheidt. “We needed a bigger gun and magazine. Everything had to look more dangerous and tactical. We did some dynamics tests with reference footage that we took from different types of drones and quadcopters.”     Details of the vehicles were important but didn’t necessarily have to be extreme. “We didn’t have to build all of the bolts and parts of the inside of the helicopters and quadcopters,” explains Asparuhova. “But you did need to make sure that there was something inside, so you didn’t end up exploding an empty shell. Especially, for the shot where the helicopter crashes into the wall and the tail comes off. We had to make sure that there were parts in the tail to make this realistic.”  Everything began with real physics. “You need to make sure that your animation should at least start on real dynamics, speed and forces,” von Overheidt says. “You’ve got creative license later on to a certain extent. But if you want your effects simulation, in particular hard surface simulations like crashes, to look real then you start as real as possible with the animation.”  Asparuhova adds, “It's always fun when you build something with the idea that it gets blown up in the end and that was most of our assets!”  The nuclear explosion in the film’s finale had to be big enough to destroy the gorge but not so massive that it could destroy a country. “We looked at a lot of reference of different types of nuclear explosions and the shockwaves that came after,” Asparuhova shares. “The shockwave is even more destructive than the explosion itself. We looked at what would happen and how that would impact the environment. All the nuclear explosion test footage that we had seen happens on flat ground. There was actually some good reference of trees bending that we had found during a nuclear explosion; that gave us an idea of what would happen with the trees. The shockwave had to happen above the actual explosion so we could see how it would impact and destroy the environment.” “Our job is to recreate reality in many cases, so you have to make sure that you’re knowledgeable about what you’re trying to create, otherwise it’s not going to work,” observes Asparuhova. “In order to make things as realistic as possible, you end up looking at a lot of pictures to make sure that you’re making the right decisions. That’s what cool about our job. In every project, you get to learn about all sorts of things.”  Discoveries get made that inform creative decisions. “There’s always a myth buster component in every project that you go through,” notes von Overheidt. “Doing research on a quadcopter flight dynamics to learn what kinds of maneuvers can they do. How do they cut corners? How quickly do they readjust? What does the muzzle flash look like on a particular gun or machinegun? What is the weight of that gun? How many rounds do you have in a magazine? In different scenarios when Levi ziplines over the gorge you come up with, ‘What is a realistic speed?’  Then you place all the cameras and realize at that distance, a background barely moves. You start finding these things out and adjust with creative license accordingly. That’s a big fun part of making visual effects.”    Trevor Hogg is a freelance video editor and writer best known for composing in-depth filmmaker and movie profiles for VFX Voice, Animation Magazine, and British Cinematographer.