| name | crawl-backward |
| description | Crawls backward on hands and knees, keeping facing, via a low translating sequence. Use when a command mentions crawl backward, crawl backwards, back up on hands and knees, or reverse crawl. (For crawling forward, use crawl-forward.) |
| category | locomotion |
| disable-model-invocation | true |
| subskills | ["move-arm","move-leg","move-torso"] |
crawl-backward
A hands-and-knees crawl moving backward, alternating opposite limbs. Translate root while OMITTING faceDeg so the heading holds.
Composes: move-arm + move-leg + move-torso
How
- Use a
sequence with loop:false. Frame root is ABSOLUTE; compute the travel axis from state.position+state.faceDeg (0=+Z, 90=+X). The example assumes origin facing +Z. Make z more negative; do NOT set faceDeg. Keep root.y~-0.55.
- Torso forward (
Spine+X~60); reach a hand back as the opposite knee follows.
durationMs ~2800.
Example
- "crawl backward" ->
{"durationMs":2800,"say":"Crawling backward.","sequence":{"loop":false,"frames":[{"t":0,"pose":{"Spine":[60,0,0],"LeftUpperArm":[120,0,90],"RightUpLeg":[80,0,0],"RightLeg":[90,0,0]},"root":{"y":-0.55,"z":-0.3}},{"t":0.5,"pose":{"RightUpperArm":[120,0,-90],"LeftUpLeg":[80,0,0],"LeftLeg":[90,0,0]},"root":{"y":-0.55,"z":-0.6}},{"t":1,"pose":{"Spine":[0,0,0],"LeftUpperArm":[0,0,90],"RightUpperArm":[0,0,-90],"LeftUpLeg":[0,0,180],"RightUpLeg":[0,0,180],"LeftLeg":[0,0,0],"RightLeg":[0,0,0]},"root":{"y":0,"z":-1}}]}}
Limits & posture
Keep ≥1 foot grounded except at a jump's airborne apex; stay inside human joint ranges and keep weight over the support — see balance-and-posture.
