BY ADAM GRACE
When the APU was required for filming, it was typically transported in seven sub-assemblies – the carriage, the upper torso, the pelvis and legs, both arms, and both guns. Also accompanying the APU was support equipment such as tools, spare joint covers and additional components for dressing to camera. So as to represent an army of APUs for the various operators, carriage components such as the overhead roll-cage and handgrips were manufactured in different styles and fitted as required. Panels with individual artwork and markings were also interchanged for each character. A series of seatbelt and seatcovers were provided by Assistant Set Decorator Marian Murray.
An articulated crane was used to lift the assemblies onto the set. For scenes requiring the APU to be lying either face down or on its side, the upper torso was attached to the leg assembly off set, and a second crane was used to help manoeuvre the APU into position. The carriage, arms, and guns were then craned onto set and attached to the APU. For shots of the APU kneeling, the carriage, arms and guns were removed, a forklift was brought in from the front to lift the torso/leg assembly, and the legs were moved into a kneeling pose. The turn-around from standing on one set to kneeling on an adjoining set was approximately 10 hours.
The kneeling APU set-ups included scenes of the APU being loaded with ammunition. The “ammo loaders” were wheelbarrow-style designs with a scissor lift mechanism to raise the ammunition box loading bed to the correct height. A functional loader was built with a hydraulic ram that pushed a cast aluminium lift assembly to a pre-determined height. A pneumatically driven pulley assembly within the loading bed pushed the ammunition boxes into the housings on the APU. Lighter, non-lifting versions were built for actors to wheel around on set. The loaders were built in the Props Manufacture Department by Simon Bethune and Rodney Nash with Steel Department Lead Hand Andy Ho.
The sets that included the APU were constructed on raised stages, with additional support beneath the APU. For safety, the APU was fitted with a support cable to an overhead truss. Power and air required for operation of the console and the ammunition housings were fed from beneath the stage and hidden amongst the existing APU hose dressing.
The motion base carriage was set up at the end of a 10m track on which ran a Milo motion-controlled camera. The action of the motion base, the camera, and banks of interactive lighting were all programmed to match pre-viz approved sequences. David Pride’s team fitted the carriage-mounting frame with a pneumatically driven shaking device to simulate the recoil effects from firing the guns. Between the carriage and the frame was a spring assembly that allowed the carriage to react to the motion base movement. This simulated the effect of a shock absorption system between the carriage and the torso of the APU. The motion base needed to move quickly to achieve the actions required and could rotate the 500kg carriage set-up through 180° in less than 1.5 seconds. Senior VFX Supervisor John Gaeta made a cameo appearance on the motion base set up as an APU operator.