Human Gait Study is a side-view animation of an adult human profile, drawn as SVG contours rather than a stick figure. The outline includes a soft facial profile, a shaped torso, articulated limbs, resting hands and fuller shoes with a movable forefoot. Optional suspension lines give the figure the appearance of a marionette.
The movement is procedural. It aims at a recognizably human rhythm and plausible foot support, but is not motion capture, a biomechanical simulation or a clinical assessment. The reference images informed the choice of viewpoint and visual simplicity; the contour geometry and animation are independently constructed.
Different Gaits, Not Just Different Speeds
A faster walk is not simply a slow walk played back more quickly. Step length, foot clearance, support duration, body pitch and arm movement change as well. The six modes therefore use different movement patterns:
- Walk: an upright trunk, a mostly extended supporting leg, low foot clearance and relaxed arm swing. Pelvis height adapts slightly to stride length so the planted feet remain reachable.
- Brisk walk: quicker cadence, longer steps, more energetic swing and a slightly forward-inclined body.
- Run: shorter support, higher recovery of the swinging foot, bent elbows and intervals when neither foot is grounded.
- Tiptoe: forefoot support, a shorter stride and quieter vertical movement.
- March: elevated swinging feet, a more upright torso and stronger, coordinated arm movement.
- Silly walk: a deliberately comic gait inspired by the idea of the Ministry of Silly Walks, with high forward kicks, a backward-inclined torso and excessive arm movement. It is an original procedural pattern, not a reproduction of a filmed performance.
Tempo changes playback rate. Stride changes horizontal foot travel while preserving the modeled limb lengths. The cycle control pauses the animation so that a particular support or swing configuration can be inspected.
Arms, legs, hands, feet and toes can also be dragged directly to inspect a pose. This pauses playback; the corresponding elbow or knee follows through inverse kinematics with fixed limb lengths and limited bending. The toe handles rotate the forefoot around its own joint. Focused handles respond to the arrow keys, with larger steps while Shift is held. Resuming playback restores the selected gait, and Reset restores the original presentation.
Feet Establish the Movement
During the stance phase, the supporting foot moves backward relative to the stationary figure at the same speed as the ground marks. This represents a person moving forward, viewed by a camera that travels with the torso. The contact point stays on the ground rather than sliding independently of it.
The foot then leaves the ground, travels forward through a higher swing trajectory and prepares for the next landing. Foot rotation changes the supporting point from heel toward forefoot. Running has a support fraction below half the full cycle, allowing a flight phase; ordinary walking keeps at least one foot in contact.
The ankle and the toe hinge are separate joints. The forefoot bends upward relative to the rest of the shoe during push-off, allowing the heel to rise while the front stays flatter against the ground. The simplified toe hinge represents the metatarsophalangeal region; it does not model every toe bone independently. Joint markers reveal its pivot, and dragging the toe changes the angle while retaining the forefoot length.
Fixed Bones, Moving Joints
Hip and ankle positions determine the knee through a two-segment inverse-kinematics calculation. Upper and lower leg lengths stay fixed instead of stretching to follow a moving drawing. The knee bends toward the front of the profile. Arm segments likewise retain their lengths and swing against the corresponding leg, with different elbow flexion in running.
The torso has a small gait-dependent vertical movement and inclination, while the head is more stable than the trunk. These phase relationships matter as much as the silhouette: limbs moving independently with unrelated sine waves rarely look like coordinated walking.
Contour and Marionette
The black contour is drawn directly over the light RAW stage and its cross pattern, without a separate scene background. Both shoes use the same geometry and silhouette rendering; their different angles come from the gait's heel-to-toe roll. Rear contours are hidden where they pass behind the near-side body, rather than producing artificial seams at the shoulder or shoes. A neutral facial profile and curved knee and foot outlines soften the figure. Strings, joint markers and ghost contours are optional visual layers, not physical actuators or a simulation of a suspended body.
The animation respects reduced-motion preferences by starting paused. A paused cycle can still be adjusted manually. All geometry is generated locally in the browser, and no image or motion data is uploaded.