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S.W.A.T.

Friday, September 5th, 2003 | Article by Jean-Eric Hénault

S.W.A.T.

Interview with Michael Hardison, Pixel Magic

This is one of these films few would consider an FX Film. One of these films where the action really takes over and makes you forget about reality and yet, seems so real you forget what you are seeing is simply yet just an other film.

S.W.A.T. brings you to the dangerous streets of L.A. (I’ve been there myself, it’s not that bad) A dangerous criminal offers one hundred million $ to anyone who delivers him from prison and it seems only the LAPD Special Weapons and Tactics (S.W.A.T.) team can prevent it.

No, they did not really crash a multi-million helicopter into the streets of LA, and no, they did not really land a plane in the streets of the city either, or did they? These are the illusions created by the men and women (okay, mostly guys) at Pixel Magic. We talk with Michael Hardison on the work they have accomplished on the film.

CGC: Give us a breakdown of the work you have done on S.W.A.T.?

MH: Pixel Magic was the sole visual effects house for all the CGI creations and compositing in SWAT. Some of the more prominent shots were the Augusta helicopter crash the and the Learjet landing sequence.
Watch the Augusta helicopter crash sequence
(Jeremy Renner plays Brian Gamble, a former S.W.A.T. member turned mercenary)

The Augusta helicopter crash sequence, which required the back to back cutting between practical and CG helicopters, was achieved by a close cooperation between the special effects crew and Pixel Magic’s on set visual effects supervisor, Raymond McIntyre. Using measurements and digital stills taken on set as reference, a CG helicopter was modeled and animated to match the action.

Clark Johnson on the set of S.W.AT. Photo credit: Merrick Morton

As the practical helicopter falls towards the men on the rooftop, a CG helicopter, blades hitting the parapet timed to practical explosions and throwing debris over the men diving for cover, takes over and spins out of control above their heads. Multi-pass rendering was used to achieve the correct lighting and depth of the helicopter within the frame. In compositing, shadows cast by the helicopter, CG debris and smoke, and a hand-held camera move were added to enhance the action.

To bridge the time from rooftop to ground, a 360o building plate was made from a panorama of digital stills shot from a Condor and composited with a Green Screen interior of the helicopter. Varying degrees of motion blur were added to the foreground and background to simulate an out of control spin.

Upon reaching the ground, a full size, but bladeless and smokeless helicopter was dropped from 75 feet in the air and exploded on impact. Covered by nine high-speed cameras, including three inside the adjacent office building with windows rigged to explode and one in a taxi that crashes into the helicopter, the challenge for Pixel Magic was to orchestrate a believable eggbeater style stopping of the helicopter blades including interactions with the ground and fire while staying firmly tracked to the helicopter. Detailed measurements taken on set were used to aid the 3D Match Moving process. Actual footage of crashing helicopters was used as reference. The sequence was pre-visualized and approved by the director. Digital speed changes were made to the practical plates to speed up the action. Multi-pass CG rendering was once again used to control lighting, depth and reflections of the fire in chrome surfaces and blades. In compositing, CG smoke, gouges in the ground, dust, and camera shake were added to enhance the action.

For the Learjet landing shots, one of the challenges in the sequence, and in fact the entire movie, was to create visual moments that enhanced the excitement and danger without going ‘over the top’ into fantasy. The story had already demonstrated that an offer of $100 million was more than enough money to induce certain people to risk life and limb. For a climax, how about landing the get-a-way plane on a bridge in downtown Los Angeles.

Intercut with Green Screen Composites inside the Lear Jet cockpit, our challenge was to animate a CG plane operated by a pilot performing a dangerous, but controlled maneuver. A flight simulator loaded with the characteristics of the Lear Jet was used to pre-visualize various moves. Once approved, the flight simulator data was converted to a 3D model of the plane. The plane was modeled and animated using digital stills as a guide of the hero practical plane that was used on the set. Detailed measurements of distances and readings of lights on the bridge were used to create a ‘virtual’ bridge lighting and reflection package. The practical photography was digitally Match Moved in 3D space. Multiple CG passes were rendered to control lighting, depth, and reflection. In compositing, the plane’s strobe lights, heat exhaust, tire smoke for the moment of impact, and camera moves were added to enhance realism.

Once on the bridge, a practical Lear Jet driven by a V8 engine was used to simulate stopping and takeoff. However, since a Lear Jet lands at approximately 150 mph, the photography was shot under-cranked at 20 fps. This meant that all strobe lights were turned off so that they didn’t appear to blink wildly. Ultimately, this was still too slow and digital speed changes were made to many plates. In addition, a Lear Jet has thrust reversers to help it stop which were inoperable on the set. Digital 3D Match Moves were made of the plane for each shot and CG thrust reversers were animated turning on and off. In compositing, the plane’s strobe lights, heat exhaust, and tire smoke were added.

CGC: How many shots in all?

MH: We had over 150 effects shots for the movie.

CGC: Do you think this film could be considered a “Non-effect” film? (Non-effects refer to a film where the effects may not be too obvious to the public)

MH: First of all, there are very few movies that come out today that have not been touched up by compositing or 3d visual effects. Even today’s romance movies, the last place you would expect to find CG animation, have been touched by the visual effects bug. The power is too compelling for directors and producers not to be able to tweak their movies in the post production realm of visual effects. The movie we are finishing now, “Under The Tuscan Sun”, is a prime example. We were called in to create subtle visual effects such as CG lightning and tile explosions, set extensions, digital matte paintings and detailed compositing. The challenge of these “non-effect” films is the need to NOT draw attention to the visual effects. With an effects heavy movie, visual effects is one of the actual characters in the show. Therefore, it is more acceptable to cast attention to it. With non-effect films, it’s obviously the opposite. Any type of the shot that casts attention to itself and away from the story just causes damage to the film. SWAT, because it was more of an action movie, fell between the lines. Some shots were meant to be fantastic, and consequently effects driven, while others effects shots just needed to accentuate the story. SWAT had a good blend of effects in it to make it both a challenge and enjoyable.

CGC: What were the most difficult parts of the film?

MH: The most difficult part is always getting the visual effects to work seamlessly with the practical footage shot. The Learjet, for example, had a particular gray painted surface that was surprisingly difficult to recreate in our surfacing. We did not expect to come across the challenge of matching this unique look. Eventually, with the help of compositing, we managed to achieve the right match of values that made it possible. But you always run across the unexpected when doing photoreal effects.

CGC: What’s next in your production pipeline?

MH: We have just wrapped up creating effects for “Freddy v. Jason”, “Torque” and “Under The Tuscan Sun”. We are currently working on the movies “Looney Tunes” and “The Last Samurai”.

Big thanks to Mike Hardison for taking the time to answer all our questions with so much details!

Also, we woud like to thank Columbia/Sony Pictures and everyone involved in the making of this story.

Related Links:

Official S.W.A.T. movie site
Pixel Magic FX

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