By TREVOR HOGGImages courtesy of Framestore and Apple Studios.A lab experiment gone wrong unleashes a toxic fog that causes mutations that need to be prevented from escaping into the world. To accomplish this mission, two guard towers were constructed on either side of the natural landmark with one occupied by a sniper from the Soviet Union and the other manned by the Western Hemisphere. Directing the Apple Studio and Skydance feature The Gorge is Scott Derrickson, who turned to Production VFX Supervisor Erik Norby to look after what could not be achieved practically.We started with a build that matched this little portion of the set, which was built and extended to be endless. Once we had done that, there were numerous discussions about how far can you see in the gorge through the fog? Is the toxic cloud sentient? Does it have its own behavior? There was a lot of look development versions to decide if it would have its own animation. We ended up with something that is a mixture.Joao Sita, Visual Effects Supervisor, FramestoreThe poisonous fog was CG so it could be art directed.When the action shifts down deep into the man-made environmental disaster, Norby relied on Framestore to produce 516 shots that include creatures known as Hollow Men and landscapes filled with atmospherics. The work was divided between Visual Effects Supervisors Pete Dionne and Joao Sita with the former situated in Vancouver and the latter in Melbourne. Visual effects artists were involved as well as the art department and pre-production team at Framestore. Its cool because this is one company where you can get all of that knowledge beforehand, so when you get to do the shot in post-production, you know the history of why this is happening from left to right, not right to left, or, I have this idea; has it been considered before? Sita states. That was great.Colored on-set lights set the tone for what was to emulated in CG.Obscuring the landscape is the prevailing fog. In the studio, they had trees, and the DP used colored lights to try to maintain some visual language and get the proper reflections and bounce, which later on we had to dial in or out depending on the shots, Sita remarks. We started with a build that matched this little portion of the set, which was built and extended to be endless. Once we had done that, there were numerous discussions about how far can you see in the gorge through the fog? Is the toxic cloud sentient? Does it have its own behavior? There was a lot of look development versions to decide if it would have its own animation. We ended up with something that is a mixture. The fog consisted of five to 10 layers that had to be art directed to not lose ones perception of the environment. We played with certain lights behind the trees to get their silhouettes through the fog or art directed the fog elements per angle or shot. There was a generic library built at the beginning, but as soon as we dropped that in, there would be lots of iterations trying to massage it to get the framing to read as expected. From the trees, there is this faint streaming element that is black and smoky; it was to enhance the idea that this forest had been through some sort of mutation or suffered from an anomaly.When we are under the mustard toxic plumes, the trees are leafless with twisted branches. In the purple environment, the trees are the ones that mutated into human or animal form. The Hollow Men were humans that once exposed to the toxic plumes, they mutated with whatever DNA was around them, and that happened with the creatures too, like the centipede that mutated into a branch-like creature or the tree roots that mutated into a crab-like creature.Joao Sita, Visual Effects Supervisor, FramestoreThe Framestore art department explores the looks for the Hollow Men and Hollow Horse as well as a crab-like root creature.Most plates had a subtle fog produced by the special effects team. The majority of the practical fog got replaced when we started doing our set extensions, Sita remarks. As soon as you have red lights hitting fog from a smoke machine you get all of this contamination of colors, so you cant rely anymore on the extractions for compositing. Also, the trees in camera had a height limit, so we had to make them taller. The trees reflect the different areas of the gorge. When we are under the mustard toxic plumes, the trees are leafless with twisted branches. In the purple environment, the trees are the ones that mutated into human or animal form. The mutants, caused by the toxic fog being unleashed by secret military labs being destroyed by an earthquake, pose a serious threat to humanity. The Hollow Men were humans that once exposed to the toxic plumes, they mutated with whatever DNA was around them, and that happened with the creatures too, like the centipede that mutated into a branch-like creature or the tree roots that mutated into a crab-like creature, Sita explains.Stand-ins assisted in getting the proper interaction with the mutants. For the Alpha, the main Hollow Men, we had an actor in prosthetics and had to replace most of his body to alter the proportions, but we kept some of the expressions, Sita states. The other Hollow Men were played by stunt performers wearing a gray suit with markers, which was a base because we had to swap quite a lot of the action with the CG version. We did a lot of mocap and animation to get the performance. The horse and centipede were keyframe animated based on real-life references, then taking in account the physics of this new character. The horse is hollow and has all of this vegetation growing inside of it, so youre going to keep it close to reality but also have a new way, such as, This should feel lighter. Were going to change the tail and mane slightly so we can imply its not a full grown and pristine horse. The Hollow Men had to appear to be hollow without raising questions as to how they could be alive and deliver a human-like performance. We never show that story, but the idea is that there are operational organs, though most of the body is vegetation or fungi or trees or bushes. There were default expressions which consisted of sad, angry and irritated. We did mocap for some of the sequences of the Hollow Men while most of the stuff involving climbing the ropes or running with the horse were purely hand-animated, Sita says.A series of explosions are set off in an effort to destroy the gorge.For the Alpha, the main Hollow Men, we had an actor in prosthetics and had to replace most of his body to alter the proportions, but we kept some of the expressions. The other Hollow Men were played by stunt performers wearing a gray suit with markers, which was a base because we had to swap quite a lot of the action with the CG version. We did a lot of mocap and animation to get the performance.Joao Sita, Visual Effects Supervisor, FramestoreBeing humanoid in nature did not make the design and animation process any less complicated. Even though they have arms and legs similar to human body shape due to the branches and construction of the body, there was a lot of massaging to make it work, Sita explains. If you had a branch sticking out off of their shoulder and they turned their head, youre going to be hitting that. There were limits that we had to put into what the performance can do, or do we take the branch and push it with the head, or do we change the position of the branch so its never in the way? It was rather interesting because we did a lot of design for the characters. When you get a design approved and everybody loves it, youre just seeing a frame of that character outside of context. As soon as you build an arm made out of branches and try to bend it, you go, Where do we have a joint? Do we make the forearm a separate piece of branches that intertwine with the elbow area? Whereas, Groot in Guardians of the Galaxy has bark that makes him more like a tree trunk, the Hollow Men are more like vines and branches. Costumes were hard to get right. Sita adds, A uniform dressed on a pile of branches or an uneven body, if it is not done in a certain way, will look odd because youll be getting pieces of fabric going through holes or the fabric might not fly with the wind or push against the body enough. There was a lot of back and forth to get settings that would work for the underlying surfaces of the costumes.Practical hybrid trees were constructed on set, which were then digitally augmented.The main challenge was how can you make that explosion feel like theres enough scale to destroy the gorge and hint that its going to happen but end the shot without telling. We chose a framing that was a wide angle looking slightly up so you could see the clouds above, and as soon as the ignition happens, it illuminates all the wall and clouds above, showing that this is going to be massive. As soon as it starts to progress, we got the shockwave, and everything turns into dust as its coming forward.Joao Sita, Visual Effects Supervisor, FramestoreMuzzle flashes and explosions were entirely CG with interactive lighting added to the characters. We were replacing much of the surroundings, so getting the interactive lighting into the fog and environment was simpler, Sita states. For the stuff happening above the gorge when theyre shooting the turrets, that is all CG muzzle flashes and recreation of interactive lighting. The towers were built in CG where they interact the most. The lookout was in-camera but the exterior was replaced. An all-terrain vehicle drives up the wall of the gorge. When Levi was ziplining between the two sides of the towers and the cable breaks, most of the cable is on one side of the wall because it didnt break in the middle. Thats why Drasa and Levi have to reach the east side. They attach the broken cable to the winch of the jeep, then pull as if you were pulling a vehicle out of mud. There was a lot of discussion as to how far from the wall it would go. Would that winch and cable support the weight of the vehicle? This is obviously cinematic magic. We have a couple of shots where you can tell that the tires are operational and touch the wall to help the winch. There is a side-to-side motion that makes it feel like the cable isnt fully attached. They shot a lot of the action with the jeep hanging on a set.The Hollow Horse in action.The most dangerous of the Hollow Men is the Alpha.Framestore produced 516 shots that focused on the environment and creature mutations caused by secret labs accidentally unleashing a toxic fog.Anya Taylor-Joy and Miles Teller in The Gorge. The VFX work was divided between Visual Effects Supervisors Pete Dionne in Vancouver and Joao Sita in Melbourne. Erik Norby was Production VFX Supervisor. (Photos: Laura Radford. Courtesy of AppleTV+)Anya Taylor-Joy and Miles Teller in The Gorge. Framestore visual effects artists, as well as its art department and pre-production team, were involved in creature creation, landscapes and atmospherics. (Photos: Laura Radford. Courtesy of AppleTV+)A series of explosions are set off in an effort to destroy the gorge. We did the initial ignition down the gorge, and the camera in our shot was too close to tell the story of the collapsing environment, Sita remarks. From that initial ignition and explosion, we could pick elements that will need to be destroyed or fractured, but we wouldnt have to collapse walls. There wasnt enough time in the shot for that. The main challenge was how can you make that explosion feel like theres enough scale to destroy the gorge and hint that its going to happen but end the shot without telling. We chose a framing that was a wide angle looking slightly up so you could see the clouds above, and as soon as the ignition happens, it illuminates all the wall and clouds above, showing that this is going to be massive. As soon as it starts to progress, we got the shockwave, and everything turns into dust as its coming forward. Between our shot down in the gorge, they put one shot from above the church, which Drasa and Levi go through as its collapsing. That helped show how far we were from the village and that the explosion has enough power to destroy it all.