rigging
Ball-joint support rig
Tie-down / Flying rig
Definition
A rigging system distinct from both the tie-down and the flying rig: an articulated arm of stainless-steel ball-and-socket joints, threaded from a small base plate positioned just out of frame, that braces a stop-motion puppet in a cantilevered or off-balance pose -- mid-stride, mid-leap, mid-fall -- that neither a floor anchor nor an overhead suspension line can hold.
Overview
Where a tie-down anchors a puppet's feet through fixed holes in the set floor and a flying rig suspends it from an overhead track or off-camera stand, a ball-joint support rig does neither: it holds the puppet from a small base plate placed just out of frame, using an articulated arm of stainless-steel ball-and-socket joints threaded together on a rod. The animator sets the arm's shape once for the shot, then adjusts only the ball-joint tension frame by frame -- the same incremental discipline used on the puppet's own armature -- so the rig can carry a pose no floor anchor or overhead line can reach: a foot planted mid-stride with the rest of the body cantilevered forward, a leap held at its peak, a character caught mid-fall.
Aardman Animations' own rig kit, sold commercially as an "industry standard design," specifies two double ball joints and one single ball joint of 6mm stainless steel on a threaded rod running from a chromakey-green base plate, sized so the joints can be swapped between armatures of different puppets. The green base plate is deliberate: like the wires on an older flying rig, the rod and joints are built to be identified and removed in post rather than hidden on set, which is why this rig type has become more common as digital rig removal has matured (see rig-removal) rather than requiring an invisible mechanical solution.
Early Man (2018) shows a rig from this same Aardman family doing that job in production: animator Claire Rolls is documented using a rig -- built on the studio's standard ball-joint support system described above -- to hold the puppets Dug and Hognob in place while she animated, with the rig painted out digitally afterward. That is the same "hold it, shoot it, remove it later" logic Aardman VFX supervisor Howard Jones describes for Early Man's rig-removal pass generally (see rig-removal), applied here to the physical support step that precedes it. The Early Man trade coverage does not itself specify the exact rig hardware used on that shot; the ball-joint identification rests on Aardman's own documented "industry standard" kit being the studio's standing support system, not on the Early Man source naming it directly.
The three rig families -- tie-down, flying rig, ball-joint support rig -- are not interchangeable: they solve different balance problems (grounded weight, suspended flight, cantilevered mid-pose) and a single shot may combine more than one, for example a tie-down at the planted foot and a ball-joint arm bracing the torso above it.
Workflow
- Identify the pose the tie-down points and the puppet's own armature cannot hold unassisted -- typically a cantilevered mid-stride, a held leap, or another off-balance moment.
- Attach the rig's base plate just out of frame (on a chromakey-coloured surface if the removal pass will key it out) and thread the ball-joint arm to a hardpoint on the puppet, usually the torso or hip.
- Shape the arm's overall geometry for the shot, then, frame by frame, adjust only the ball-joint tension to match the incremental change in the puppet's own posed movement.
- Shoot the frame; advance the puppet's armature pose as normal, re-adjust the rig's joints to match, and repeat for the run of the shot.
- In post, remove the rig and its base plate -- rotoscoped frame by frame or against a tracked clean plate -- following the same rig-removal pass used for tie-down and flying-rig hardware.