Our Inception coverage is in two parts. Click through for a detailed discussion with the team at New Deal Studios by Ian Failes. And also to access our in depth podcast with Visual effects supervisor Paul Franklin of Double Negative in London. We have delayed publishing both as they contain heavy spoilers on what must be one of the year's best films.
Double Negative were the primary visual effects facility on Inception. They had worked prior to this film on both of Nolan's Batman films and in this week's podcast Mike Seymour has an in dpeth discussion with Double Negative's Paul Franklin, who was visual effects supervisor on the film. Double Negative did incredible work from the Paris folding scenes to Limbo - land and all the wire rig, set extensions and bold visual effects in between. We strongly recommend you sit back and enjoy this week's podcast (but only if you have seen the film - as it will spoil the film to hear the podcast first).
New Deal Studios
For Christopher Nolan's Inception, New Deal Studios handled effects for the explosive demolition of the hospital, a massive concrete structure perched on the edge of a snow-covered mountain, that exists inside the dream world. New Deal's Ian Hunter gives us the low-down on constructing the hospital in miniature and blowing it up - twice.
Planning and previs
Visual effects producer Mike Chambers and overall visual effects supervisor Paul Franklin sought out New Deal to build just part of the hospital fortress as a miniature for demolition. This was made up of a tall tower and main building, along with an adjacent structure which connected the tower to the main building. "Because in the film it pans out as a controlled demolition, both Paul Franklin and New Deal, separately, did some preliminary previs to show the sequence of these buildings falling to get the timing right," said New Deal's miniature effects supervisor Ian Hunter. "The idea was to work out camera angles which we were basing the amount of build we would do on, and also set up the choreography of the buildings as they fell."
New Deal settled on a scale of 1/6th for the miniature build after looking to the art department's concept sketches. "This scale was dictated not only by cost, but also the fact that we were shooting in our backlot at our facility," noted Hunter. "We had to figure out what was the biggest thing we could fit in this space and still get our cameras in position and shoot. The other thing about the scale was that we wanted it to be as big as possible because we were having some explosions and fire and obviously the bigger the scale the better they look on film."
A simple model of the complex was built in Rhino software and then subdivided into the many pieces that needed to be constructed. "Since we had a 3D model to build from," added Hunter, "the mechanical effects guys could also design their rigs in 3D and fit them into the model before we actually did any construction. It's very complex to get all the mechanical effects in there. There's a lot of clearances involved. When the buildings are collapsing, we actually had holes in the mountain just slightly bigger than the base of the building and the idea was that as they collapse the buildings would be pulled down and crushed. The size of the holes needed to be worked out and the people doing the buildings were working independently of the people building the mountain, so all of them needed to be working to the same numbers in order for things to be able to fit together."
Once construction of the miniature began at New Deal, Double Negative continued the previs effort for the sequence of explosions, which was shown to director Christopher Nolan for approval. "That resulted in the explosions starting at the front of the tower and at the base of the support struts that hold the tower up," said Hunter. "The idea was that these support struts get blown up in a sequential manner and then proceed to go further back into the adjacent building and then take out the support struts on the main building."
A mechanical underbelly
With previs helping to set out a pre-determined choreography of the demolition, New Deal was tasked with bringing the structure down in an independently controlled mechanical manner. "We knew that we didn't want to build this model and bring it down randomly to try and match the choreography," said Hunter. "So the build of the miniature was important, but just as important was the mechanical effects used to collapse it which matched to the pyrotechnics. We also had to adjust the timing to match the approved previs and also adjust that on our shoot day."
Ultimately, support struts viewable to camera were built as faux breakaway pieces rigged to blow up, although these did not function to hold up the model. Instead, New Deal relied on scissor jacks hidden by the model detail to control the falling structure. "They're similar to scissor lifts that painters use," said Hunter. "We built smaller versions of those with hydraulic controls that could collapse. The jacks when extended could hold the building up and then we could trigger the hydraulics to collapse the scissor jacks and eventually bring the buildings down. That way the building motion was independent of the pyro."
Demolition of the prominent tower relied also on a hydraulic scissor jack that lowered it down. An internal steel frame was cut into several pieces and had its own set of trips and pull cables. "When it got to a certain height there was a switch that released all the trips and also primacord that was laced inside the building so that it looked like it had impacted onto the rock as it fell," said Hunter. "That impact would cause a shockwave that would crack the building apart and it would come down in several pieces. The direction of falling buildings and the tower, was determined by hinges inside the steel frame."
Another aspect of the demolition involved the manner in which the main building, constructed like an inverted pyramid with the top floor larger than the bottom floors, would fall away. "Chris wanted to see it falling from the bottom up," recalled Hunter. "The bottom floors would fall off before the rest of the building fell down. So we made it so that each of the floors were supported by a steel finger that we screwed the floor onto, and those steel fingers were attached to a release with a steel cable. Imagine there are eight floors on the building and each floor was divided into six pieces, so there were 48 individual sections of floor attached to these steel fingers and each finger has a release trip that's on a cable. All of those cables go into what we call our 'harp' which is a frame that holds each of the cables in line. As these cables are being pulled back, there's a little trip in a sequential manner that's attached to each cable and the distance they were pulled back equated to the time the floors would fall. We could set the floors to fall starting from the bottom up and from the centre out, basing the timing on frame counts from the previs."
The right materials
The hospital fortress set built by production was designed as a heavy-cast concrete structure, the look of which had to of course be replicated by New Deal's miniature. After visiting the location in Calgary for photo reference, Hunter looked for a suitable construction material that had to be fragile enough to come apart and break in a certain manner. "We also realised that between holding the buildings up with hydraulics and with all mechanic effects rigging there was a lot of weight involved in that alone," explained Hunter, "so the models themselves couldn't be made of something too heavy like concrete or plaster because they would not have been able to support themselves. We needed something that was lightweight, but fragile, and could break up on its own. We ended up making patterns for all of the buildings, then making the moulds and then had a combination of spraying plaster into the moulds to give us a cast concrete concrete look, but backing it with two-part urethane foam that we would pour in which was both lightweight and fairly fragile for the sizes we were using."
New Deal artists made hundreds of wall sections, floors, railings and other parts that could go together and then be built up as a facade before being screwed to the steel fingers, which did the job of holding up the respective building. "We would score the back of the urethane so that when the buildings came down they would hit rocks or each other and break apart," said Hunter. "The plaster gave us the fracturing on the surface that would look like concrete and the urethane would also tend to fracture because we had scored it on the back." Windows in the buildings were made of very thin single strength glass to give an additional effect of shattering as the building came down.
For surface areas like floors or roofs, sheets of urethane foam were pre-cut in different thicknesses and plastered with a trowel. "In one of the shots," recalled Hunter, "the floor comes down and shatters into a million pieces. That was just by virtue of that material being very weak. We tested a lot of materials and some are durable enough that they just flex and bounce. The urethane has a failure point. Once it bends enough it just shatters or splinters along a seam. We took advantage of that to get the look of concrete breaking apart. Everything was also painted in a nice concrete colour."
For the mountain itself, New Deal made patterns for the rockwork, then cast urethane skins and applied them like carpet to a framework. They were backed with urethane foam to make the structure more rigid. "We found this company that could spray urethane really well," said Hunter. "It was the same stuff that they spray onto pickup trucks as bedliner material and we sprayed that into moulds and then make these skins of rock. We laid those skins over a framework and to make it rigid we sprayed a higher dense foam on the back sides."
Pyro materials were referenced from first unit photography explosions being handled by special effects supervisor Chris Corbuld. "He had done a lot of explosions in Calgary and I got to see some of them," recalled Hunter. "They had a very distinct look, so we mixed up some materials that let us simulate that look at our end. The hope was that our explosions would match in colour and texture to the full-sized ones. That way they could intercut our footage with theirs without having any stylistic change between the shots."
Building it up on the backlot
The miniature, made up of a mountain piece with the buildings, was constructed in a modular fashion on New Deal's stage and then assembled on the facility's backlot. "The tower ended up being about 40 feet up in the air," noted Hunter, "so we had to figure out a way to hold up all of these structures and mechanical effects. What we came up with was stacking shipping containers like Legos. We had about eight of these containers all stacked up forming the under-contours of the mountain. Then the mountain pieces would be added to that. Then we literally welded our framework for all the building scissor jacks to all the containers, so it was actually a very solid foundation."
Over the course of three days, I-bolts were welded into the building frames and then a construction crane used to lift them into place on the mountain. All the buildings on the mountain were then covered in a snow material to give a fluffy dust effect as the buildings fell. "We used two materials for that," said Hunter. "One was flocking that they cover Christmas trees with and the other was just common table salt. We used about 2200 pounds of it to cover the mountain and the buildings." As the shooting date drew closer, Chris Nolan, having seen photographs of the miniature under construction, requested that some establishing shots be taken before it was blown up. "That made us feel very confident," said Hunter, "that at least the model was of good enough calibre that it would hold up for establishing shots."
New Deal covered the demolition scene with five camera angles, including a technocrane designed to work as a helicopter shot. "In the previs we had four camera angles that were down low looking up at the building giving a very ominous view against the sky," explained Hunter. "Chris Nolan also wanted to have a master helicopter-type shot that showed the sequence of events. We wanted to shoot it with a technocrane because that let us do a swing and pan and tilt and get a very fluid motion that would match the motion of, say, a Wescam from a helicopter. The problem was technocranes aren't quite tall enough - remember this model was over 40 feet high off the ground - and we had to get above the model to look down on it." In order to get the technocrane up to the desired height, New Deal brought in a 108 tonne Champion construction crane, hung a platform off of that, and then put the technocrane on the platform and brought the platform up to 70 feet.
Blowing it up on the backlot
The demolition sequence itself was made up of more than 200 events and timed to last for five and a half seconds. "Each column that supported the model blew up but then also had a trip that releases," said Hunter. "Then there were separate pyrotechnic explosions that would be illuminating the model in a certain order. Plus there were the scissor jacks that bring the model down. Then each of the fingers that get retracted and drop the floors. All of these pieces could be timed separately. We had four pyro timing boxes that had these pre-programmable timers on them, and they were all daisy-chained together so that one would go through 48 channels and so forth to fire all this off."
Two takes were shot of the demolition at 72 frames per second. "We had built duplicate breakaway walls and a duplicate tower," said Hunter. "All the mechanical effects and the guts of the model were recovered from the first take. We had to re-install new skins for the scissor jacks but then just repeated the process. It was about a week's turnaround. This also gave Chris a chance to look at the first take and make some adjustments for timing and size of the pyro. The other advantage was that we could move the cameras around and get different angles. Instead of five angles, we now potentially had eight to play with."
Although everything was essentially pre-programmed, Hunter handled co-ordination of the demolition timing himself. "I've found over the many years of me doing this, I usually end up being the guy on the trigger who anticipates the timing. We rehearsed the helicopter shot several times and I put timing lights on the model itself and I pushed the button to get the timing lights to go off so we could watch that video playback to see when we wanted to start. I showed that to Paul Franklin and he would make some adjustments. Once we got that set, I literally could do a count in my head and watch that moment, then I would do the trigger."
With the entire demolition having been previs'd to determine the choreography, the New Deal crew knew ahead of time what would happen once that trigger had been pushed. "That meant I could literally tell the camera operator to tilt up at a certain point and when particular buildings would fall," said Hunter. "By pre-planning with 3D, pre-testing with pyro and pre-testing a collapsing rig, we could do that. We actually built half of the buildings, put all the fingers in, the trips and would shoot that on video to verify the technique. We also have a model of our parking lot and all the buildings around it so knowing what day we were going to shoot, we could actually determine the sun angle to match the lighting from Calgary and that determined the orientation of the model in the parking lot. It ended up being cocked over at 22 degrees from our fence. It was very imperative that we had a plan of action, because once the model went down that's where it was going to stay."
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