What are the four key poses of a walk cycle (contact, down, passing, up), what does each mean for the head and legs, and how does mood change them?
Problem. AI motion and hand animation both need a checklist to judge whether a walk is physically plausible and expressive. Conditions. Biped walk cycle, 2D or 3D, course material. Method. Contact: one foot planted, the other just landed (heel first). Passing: the moving foot passes the planted one. Contact and passing alone give a choppy but physically sound walk. Down (after contact): head lowest because the landing leg is bent. Up (after passing): head highest as the passed leg lifts on its toes. Eight key poses make the base cycle; arms swing opposite to legs; adjust timing with in-betweens or extended frames. Mood: for a sad walk reduce up/down height difference, lean forward, droop arms, hold contact and down longer than pass and up. Inference (mine) for AI checks: plot head height over the cycle (one minimum after each contact, one maximum after each passing), check foot-plant speed near zero at contact, check arm-leg opposition. Limitations. One course page; frame counts var...
Structured fields
{
"citations": [
{
"url": "https://openlab.bmcc.cuny.edu/ani-260-1300-intro-2d-animation-sp-2021/?p=386",
"note": "Key poses; Key poses; Mood; Mood"
}
]
}Evidence claims
- [sourced_fact] Problem. AI motion and hand animation both need a checklist to judge whether a walk is physically plausible and expressive. Conditions. Biped walk cycle, 2D or 3D, course material. Method. Contact: one foot planted, the other just landed (heel first). Passing: the moving foot passes the planted one. Contact and passing alone give a choppy but physically sound walk. Down (after contact): head lowest because the landing leg is bent. Up (after passing): head highest as the passed leg lifts on its toes. Eight key poses make the base cycle; arms swing opposite to legs; adjust timing with in-betweens or extended frames. Mood: for a sad walk reduce up/down height difference, lean forward, droop arms, hold contact and down longer than pass and up. Inference (mine) for AI checks: plot head height over the cycle (one minimum after each contact, one maximum after each passing), check foot-plant speed near zero at contact, check arm-leg opposition. Limitations. One course page; frame counts vary (page cites 8 vs 12). Date. 2026-10-23. · locator: Key poses; Key poses; Mood; Mood source
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