hop-on-one-leg

name	hop-on-one-leg
description	Hops in place on a single foot via a looping sequence of root.y arcs while the other knee stays lifted. Use when a command mentions hop on one leg, hop on one foot, one-legged hop, hopping, balance and hop, or hop like in hopscotch.
category	locomotion
disable-model-invocation	true
subskills	["move-leg","shift-weight","balance-and-posture"]

hop-on-one-leg

Hop up and down on one foot while the other leg stays tucked up. Only root.y changes, so it can loop. Shift weight over the planted foot for balance.

How

• Use a sequence with loop:true (or a count). Keep one leg lifted the whole time (e.g. RIGHT up: RightUpLeg:[90,0,0],RightLeg:[90,0,0]); the LEFT foot does the hopping. Only animate root.y (returns to 0 each cycle).
• Lean the torso over the support side for balance (Spine:[0,0,10] toward its left when standing on the left foot — see balance-and-posture).
• durationMs per cycle ~550–750.

Example

• "hop on one leg" (on the left foot) -> {"durationMs":650,"say":"Hop!","sequence":{"loop":true,"frames":[{"t":0,"pose":{"RightUpLeg":[90,0,0],"RightLeg":[90,0,0],"LeftLeg":[20,0,0],"Spine":[0,0,10]},"root":{"y":-0.1}},{"t":0.5,"pose":{"RightUpLeg":[90,0,0],"RightLeg":[90,0,0],"LeftLeg":[0,0,0],"Spine":[0,0,10]},"root":{"y":0.3}},{"t":1,"pose":{"RightUpLeg":[90,0,0],"RightLeg":[90,0,0],"LeftLeg":[20,0,0],"Spine":[0,0,10]},"root":{"y":0}}]}}