animation
Walk cycles in stop motion
Timing, spacing and arcs in stop-motion animation / Animated loops in stop motion
Definition
A walk in stop motion is the same sequence of key poses that drawn and computer animators use -- contact, down, passing and up, mirrored for the second step -- but performed with a physical figure that must stand on one foot between every exposure. The craft problem is therefore as much about support and registration as about timing: each planted foot has to be held in place, and the walk can only be as smooth as the animator's control over a body that gravity is always pulling over.
Overview
Every walk is a controlled fall. The body tips forward, a leg swings through to catch it, and the weight rolls over the planted foot before the next fall begins. Animation teaching breaks that into a small set of key poses. In the version Wobbe F. Koning's walk-cycle notes attribute to Richard Williams's The Animator's Survival Kit, a 24-frame cycle puts the contact poses (heel of one foot and toe of the other on the ground) on frames 1, 13 and 25, the down poses on 4 and 16 and the push-off poses on 10 and 22, with the passing pose -- the legs crossing, the body slightly raised -- halfway between contacts. That is twelve frames a step: a brisk, purposeful walk at 24 frames per second. Lengthening the cycle slows the character down and changes who they seem to be; shortening it moves toward a run.
None of that is specific to stop motion. What is specific is that the passing pose, which a pencil draws in a second, asks a puppet to balance on one foot. Joel Brinkerhoff's walk notes on Animate Clay describe gravity as the medium's 'primary nemesis' in exactly these shots, and the standard answer is the tie-down: the armature foot has a split channel at the toe, the animator marks and drills the floor where that foot will land, half-drives a screw, slides the foot onto it and tightens it, and then carries the whole body on that one anchored foot until the other is ready to plant (see Tie-down). Electromagnetic plates under the stage are an alternative for metal-footed puppets; Brinkerhoff found loose strong magnets snapped the foot out of position. For jumps, runs or a character with no room for floor holes, an external support arm removed later in post replaces the tie-down altogether (see External puppet support rigs and Rig removal).
This is why walks are the classic test of a stop-motion animator and not merely a beginner's exercise. The poses are well known, but holding them is physical: a foot that slips a millimetre between frames reads on screen as a skid, and a body that rises and falls unevenly reads as a limp. Professional set-ups answer this with registration aids -- floor marks, a surface gauge pointed at the hip or head to track the up-and-down arc, and onion-skinning against the previous frame to check the spacing before each exposure (see Surface gauge and Onion-skinning).
The cycle also scales down to the smallest figures. A brickfilm walk tutorial on Stop Motion Film Tutorials builds a basic cycle from just eight pictures, which it presents as suitable for 12 to 15 frames per second: a neutral pose, a lifted leg with the arms swinging in opposition, a balance on the baseplate studs at the top of the step, and a weight shift onto the front foot -- then the same again on the other leg. It warns that the bare cycle looks mechanical, and recommends adding a head turn, hand movement and a change of posture to carry mood. That is the point worth holding on to at any scale: the four or eight key poses get a figure across the frame, but personality lives in what the animator adds on top of them.
Workflow
- Decide the walk's speed and character first, and set the cycle length to match (for example 12 frames per step at 24 fps for a brisk walk; fewer pictures if shooting on twos or at 12-15 fps).
- Plan the footfalls: mark every contact position on the floor or baseplate, and drill or prepare tie-down points before the first frame if the puppet uses them.
- Block the contact poses, then the passing poses, checking that the body is highest at passing and lowest at the down pose.
- Animate straight ahead between keys, keeping the planted foot locked and tracking the hip or head with a surface gauge or onion-skin overlay.
- Mirror the cycle for the second step, then layer secondary action -- head, hands, posture -- over the basic poses.
- Play the take back as a loop to check for skids, hitches and an uneven rise and fall before moving on.