A breakdown of the 20-minute oner crashes, helicopter smashes and other fiery effects in the film.
Sam Hargrave’s Extraction 2, currently streaming on Netflix, features several large set piece moments, including a masterful 20-minute-plus oner moving from a prison breakout and riot, to vehicle chase, train fight, and a daring helicopter drop-off and subsequent chopper crash.
Later, there are more helicopter scenes, and crashes. It’s a film that leans heavily on the stunts and practical effects, while also making significant use of digital visual effects.
To help orchestrate the practical effects side of those scenes, Hargrave enlisted special effects supervisor Dan Oliver.
Here, he tells befores & afters about the very specific tools and techniques used to deliver crash moments and a number of atmospheric effects for the film.
b&a: Tell me about various helicopter mock-ups and gimbals utilized in the film?
Dan Oliver: We made a fairly simple helicopter gimbal. There was a specific shot when they escaped from the top of the building and the helicopter peels off the side of the building. That was a very specific move. We built a three-axis gimbal. It could roll and it could pitch. We built a gimbal for that and mimicked that specific move.
We actually had Fred North, the pilot who was actually the pilot on the day, he jumped in the chopper gimbal for us and actually sat in the pilot seat and helped us tune the move. So, we had a move that we thought was about what was right from watching the footage. But Fred got in and he said, ‘Oh, no, pitch it down a bit more, go a bit more sideways, hold it for longer, then straighten up.’
Then, on the shoot day, we jumped in and did that exact move over and over again. We said, ‘Fred North sat in there. He said that’s exactly what he did.’ It worked really well.
b&a: Well, if Fred North says that that’s the move he did, then that’s what it was, right?
Dan Oliver: [laughs] Yes. I mean, he was there on the day in the actual helicopter when we did the wide master, so he knew what it felt like. He actually told us, ‘This gimbal is pretty good. This really mimics what the feeling is.’ That’s what you want to hear.
b&a: There’s also the chopper crashes. How did you help orchestrate those?
Dan Oliver: There’s quite a few choppers crashing during the train sequence. For those crashes, you can’t crash real helicopters. Fred would fly close, as close as he could get, as if he was coming in to crash, and then he would peel away. We’d then do a fireball off the back of the train. The CGI wizards would continue that helicopter in and crash it into the ground and enhance the explosion and have snow flying around, just to make it a much bigger event. We could only go so big with explosions on the side of a moving train because Chris Hemsworth was really there, he was actually not that far away at all. We did fairly sizable fireballs, but we would keep it safe. VFX then enhanced the rest.
Then there’s the helicopter crash at the tower block in Vienna. For that one, we did actually crash a helicopter buck. Special effects made up some shapes, about the right dimensions with the side doors open. We did some testing with fireballs inside that shape just to see how they enveloped in the shape and came out the doors. We did quite a few static tests and then we did some tests in Prague. We hired a big crane and set up a zipline between the crane down to a point and we slid the helicopter shape down the wire and then released it to crash.
Then, for the shoot in Vienna, we got a big crane and put it up on this walkway, which I was actually surprised the engineers let us do. It just worked. We managed to get this massive crane up there and ran our zipline down to the crash point.
We had a van down at the crash point. We gutted the van, took the internals out of the van and filled it up with concrete blocks, and then put a steel frame in with a strong point. That was at the other end of the zipline because we needed to attach it to something. It was actually inside that van. Then, we winched up a new helicopter shape that the Czech art department and construction team had built. It was actually a really awesome buck with a curved steel shape. They made a really accurate shape. I was bummed to actually burn it and blow it up!
Anyway, we pulled it up the top of the crane and then ran it down the zipline. We had multiple charges inside the back on a radio remote with a timer set up so, at a certain point, we could ignite them and that was ‘boom, boom, boom’ with all the fireballs happening. As it’s sliding down, you’re getting the flames leaking out the side. Then on a certain cue, which was just a visual cue, we released the main hook that held onto the line so we could drop it onto the ground and get it to roll into the van.
It was a one-take-wonder. It’s not like we could easily set it up again, but it just worked really nicely. We got the practical fire effects. We got the impact with the ground and then visual effects added a bit of dirt flying around.
b&a: With the train sequence, I imagine you shot some of that in a train carriage mockup. In the same way that you had a gimbal for the chopper, did you have any special setup for the train to create a sense of movement?
Dan Oliver: Yes, we did. We built what we call an airbag gimbal. Basically, we had the full carriages dressed exactly like the real train. Then we put that on airbags. The airbags lift up to make the carriages feel like they are floating. Then we have hydraulic rams to make it jostle and shake around.
In the film, when you’re inside that train, you’re seeing a lot of that fight action on that airbag train carriage on the stage. We shot some of the real train sequences before we shot the on-stage stuff. While shooting that, I actually got my iPhone and took some footage to see what things like the lights inside the train did, how they moved. When we jumped into the stage, we did some rehearsals just with me and my team and we found a movement with the guys on hydraulic levers going back and forth, back and forth, trying to mimic that move. What was a very good telltale was just the hanging lights. We got the lights looking the same as what they did on the real thing.
b&a: In the oner, there’s a large section in the jail yard and I wondered how much real fire and other snow or dirt effects were used there?
Dan Oliver: First of all, there were a lot of soft weapons for the fight sequences and bits of soft ground added down for the impact of all the performers. Then, all the snow you see, that really fine, fluttery snow, that was all in-camera. Some of the flames were real, some were visual effects. Chris actually did do some of that part where the Molotov cocktail gets thrown. For the Molotov cocktail igniting on the shield, we shot elements for that. We did that as an element shoot and then VFX composited that in, but Chris did actually put flame gel on his arm and his arm was on fire for some of that.
It was very crowded and it was quite a chaotic fight, so we had to be very careful where the fire was put for safety reasons. There is quite a bit of digital fire in there for that reason. Some of the prisoners are standing around little fire drums, keeping warm. They were all real. Then there’s a lot of smoke and haze, that was all in-camera.
b&a: When it gets to the car chase, there are a lot of key moments in there. What approach did you take to any particular rigs that let you crash the cars, or with the use of dummies?
Dan Oliver: For flipping the cars, we used a combination of methods. The first was what we call a pole cannon. That involves actually pushing the pole out the bottom of the car using high-pressure nitrogen. It acts like a pneumatic ram and flips the car over. We also use what we call punch rams or cannons. Rather than shoot the pole out and leave the pole behind, this is a high-pressure ram which shoots out and then sucks back in again so that it lifts the car over but then doesn’t leave anything behind.
You can see in the oner behind the scenes footage that Sam is right in there with the camera. He’s hanging off the edge of these little Polaris buggies. We built platforms on those for him and added additional roll cages and rigging points so he could be hanging off the front or the back of that right in there next to these flipping cars. It’s just too dangerous to use a pole cannon for those kinds of stunts, where the pole gets left behind. That’s because either his vehicle could run into it or sometimes they’d flip out the side and that’s way too dangerous to be that close. That’s why we use the punch cannons. The punch cannons aren’t always quite as powerful as a pole cannon, but they were enough to flip cars and get what Sam needed.
There’s one shot where a Lada four-wheel drive blows up and flips. On that particular one, because of the size of the explosion needed, it was a bit too crazy to put a stuntman in. So there we did what we call a tow-in. We had a line connected to the vehicle. We had a stunt guy and another car driving in another direction that the camera doesn’t see. He’d be driving and trying to keep his speed exactly right to match Sam’s speed in the camera vehicle and then the explosion was fired remotely from another person at right angles just so he could get the timing right. We had dummies inside the exploded vehicle.
We also had dummies on motorbikes. There’s a couple of scenes where you see motorbikes get taken out. For one of those shots, we built a track where we towed the bike in on a track and then had it hit a log, the bike flips over and the dummy flies off and explodes because he’s had a sticky bomb stuck to him. That was good fun.
b&a: I have to say, Dan, I’ve seen the dummies in the behind the scenes and they are really convincing. I’m sure there’s a tendency to do digi-doubles these days as well–and there probably were–but there was something very convincing about the dummies. Because it’s a oner, you never felt like it was cutting away from real to digital, even if of course that was part of the final work.
Dan Oliver: Yes, Sam, from day one, wanted to get whatever he could in-camera. That’s the brief, “Let’s get everything we can in-camera.” He always knows there’ll be times where you can’t, or something doesn’t go exactly how you want it to, or it’s not safe.
That’s when he’ll use visual effects and there ends up being hundreds and hundreds of visual effects shots, but you start off with the brief of just trying to make it all in-camera and that includes using dummies.
If there was a shot where the dummy looks terrible, then they can do visual effects work and erase it and do a digi-double. Luckily, the dummies perform pretty good.
b&a: There’s the final part of that car chase where the car crashes over and they’re able to get out, but again, that was very convincing and looked as if people were in it. How did you orchestrate that particular one?
Dan Oliver: That’s when the G-Wagon flips onto its side. That was another one that used the punch cannon. Sam was chasing that one, hanging off the front of his little ‘Sam-mobile’, his Polaris, and that was a punch cannon and an explosion. It flipped onto its side, and then you very quickly cut to the car on its side, them getting out and running away. You look back and you see the other Land Rover explodes and flips. That was all done in-camera. We put what we call a car flipper under that Land Rover. As they’re running away, we have the explosion go off on the off-side of the car via car flippers under the car.
They’re like a big rat trap, that It flips the car over, so we just had to do a couple of rehearsals. We knew where the car would land because we’d rehearsed that. We just watch him run and say, ‘He’s done enough steps now. He’s going to clear. He’s going to be safe.’ It’s just trying to get it as tight as you can with the actor in the shot.
b&a: In the Vienna scenes, there’s one particular part where the chopper is gunning down the suite they’re in, and there’s just so much destruction in the room with squibs and whatnot. I thought it was beautiful. Tell me how your work was featured there.
Dan Oliver: That was a set built on stage in Prague. We knew that the chopper would start at a certain point outside the windows and come around the building and shoot up the set. Our brief was just to get as many squibs as we could in there. Our set decorator would put plants in the right spots and add dressing, furniture and pillows in all the spots where we put squibs.
Then my boys rigged as many squibs as they could. There were hundreds of squibs in there. We had hits in plaster, we had hits on plants, we had hits on the floor, hits in pillows, all the glass getting shot out. That was weeks of work that went into the planning and the preppng of all the props.
b&a: Finally, I wanted to ask you about glass. There’s glass in that awning fight, for instance. How do you approach glass as a practical effect?
Dan Oliver: For dressing and for blasting around out of air cannon, we use a lot of silicone glass. That’s soft, spongy glass but it looks very convincing. For the awning where they fall through, we did some shots where we replaced the awning glass with finished sheets of tempered glass, and then we exploded them and they shatter. \Some people can fall through them. Sometimes we would just pull the whole panel out so they could slide over where that glass would be and fall through. There’s some very good VFX work in that scene, too, where there’s no glass at all and they’re doing all the cracking and the falling all in post.
For that scene, we did a trap door where we had a piece of glass. It could just fall away very quickly so that we could fall over, get to the spot, and then fall through it. That required a trap door mechanism and our glass panel, which doesn’t break but forms the floor of the trap door that had to be painted out, with CGI glass cracking and breaking put in. It was another great combination between special effects and visual effects to make it all work.
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