VFX supervisor Matt Kasmir of Nvizible shares the challenges of creating
and animating the legs of the graceful but deadly Gazelle in exciting
fight sequences for ‘Kingsman: The Secret Service’.
Nvizible Takes a Leap for ‘Kingsman: The Secret Service’ |
Among the motley crew of characters in‘Kingsman: The Secret Service’, the villain’s henchman Gazelle is the one of the most memorable. A woman of few words, what she lacks in dialogue she makes up for in her graceful but deadly fight manoeuvres, aided by a pair of steely prosthetic lower legs fitted with razor sharp blades. |
Performance PlusNivizible came on board the production about three months before the shoot, in August 2013, to begin planning their approach, and therefore were confident about what data and images they would need from set. “We contributed quite a lot to the design of the legs and blades, and carried out a series of animation and motion tests to determine what kinds of movements would both look elegant and enhance the shots,” saidNvizible’s VFX supervisor Matt Kasmir. |
Shots featuring the fight scenes required her to leap through the air, avoiding gunfire and extending her blades. The actress Sophia Boutella was able to perform many of the dramatic fight moves herself, which was helpful because the director Matthew Vaughan wanted to keep the performances within the realm of believability – extreme and impressive but realistic, not relying on digital doubles for more than a few frames at a time. |
High Frame RatesBecause Nvizible was to replace her lower legs in post with a CG prosthetic, they needed to be able to see her feet clearly in every shot, whether she was wearing high heeled shoes or was barefoot. The high action performances made this challenging and therefore they captured every shot with a witness camera so that they would have an alternative view to the hero camera in case a prop or another character obscured their view. |
The high speed photography required for the slow motion was captured with the production’s ARRI ALEXA XT hero camera for shots up to 120 fps. For those up to 300 fps a RED camera was used, and a Phantom for others up to 600 fps. |
Multiple Passes & Motion ControlMatt said, “Some of the shots required multiple passes for various reasons, including safety. When several actors were to appear in the same shot and had to jump over each other, needing a safety rig, it was sometimes better to shoot them separately and combine the shots in post. Stunt actors were used as well and sometimes had to transition to the lead actor within a single shot. For these situations, we planned out the multiple takes precisely and captured them with motion control set-ups, using cameras and a team fromThe Visual Effects Company, also in London.” In one case, The Visual Effects Company’s High Speed 360 rig was used, which spins through 360° around actors performing on a static platform. A lift column and a special head are a part of the system, so that the camera can rise and fall as well as pan and tilt with focus and zoom during the rotation for more control over the shot. Due to the mechanics and varied inertias involved, the configuration was a bespoke design and had to be adapted to suit the individual shot. |
Roto-animationFlexibility was key. In one shot, for example, there were as many as four performers to coordinate, and occasionally, the Nvizible’s artists needed to blend a stunt actor to a digital double to the main actor – in a single shot. In such cases, CG doubles were created based on comprehensive body scans, and used as a ‘bridge’ between live action and digital elements. While on set, video overlays were used to monitor how well they would be able to line up these elements in post, when they would use roto-animation to invisibly align and blend the live action with CG. |
The team also shot their own clean plates while approximating the same camera moves. Because Gazelle’s metal legs are very thin, Sophia wore green leggings on set with tracking markers, which were keyed out and replaced with the CG elements and the background material. The clean up work around her sometimes had to be projected in 2.5D to accommodate the camera moves. www.nvizible.com |