Jump
An experimental takeoff recognizer using local body rise and bilateral support evidence.
Purpose and applicable path
This article focuses on V3 jump inside the historically named GameplayMotionRecognizerV2. It is distinct from legacy calibration-relative jump. The default Runner Demo Assist profile has a separate observation boundary around V3 evaluation; V3 alone is not the whole default profile.
Inputs and required joints
JumpLocalReference preserves current-local body, hip and shoulder origins, torso scale, provider and calibration identities, reference versions and support kind. It needs core shoulders and hips plus available bilateral support pairs: ankles, heels or foot indices. Knee features have separate availability flags.
Features and normalization
RootRiseFromEpisodeOrigin means rise of the shoulder/hip body midpoint, not hip rise alone. HipRiseFromEpisodeOrigin and ShoulderRiseFromEpisodeOrigin remain separate. Support rise and velocity, current support proof and derivative availability are also recorded. Lengths are relative to the local torso scale; velocities are those ratios per second.
Thresholds and adaptive floors
| V3 variable | Value | Meaning |
|---|---|---|
EntryRise | 0.006 | Initial local-rise floor |
BodyCoherentVelocityFloor | 0.35 | Body, hip and shoulder upward-velocity floor |
LocalRiseFloor | 0.018 | Full-takeoff local-rise floor |
ConfirmationSamples | 2 | Distinct confirming observations |
StableRearmSeconds | 0.080 s | Stable rearm setting |
RefractorySeconds | 0.160 s | Re-emission inhibition setting |
RecoverySeconds | 1.200 s | Recovery setting |
Separate support rise and velocity floors derive from synthetic evidence constants. Adaptive floors in mathematics can increase thresholds based on local noise. This table is not the complete decision rule or a measured latency result.
Temporal rules and state transitions
InitialTakeoff and FullTakeoff are separate conditions. Full takeoff requires coherent body, hip and shoulder upward velocity, local rise and bilateral support departure evidence. A preload-to-takeoff reversal can use adjacent observations only with the same reference, increasing sequence and a valid interval. It does not bridge a continuity gap.
Confidence and false-positive risks
JumpFeaturesUsable requires valid tracking, references, core features, derivatives and current support proof. Crouch release, upper-body lift, missing feet and vertical bob need to be distinguished from takeoff. Image-plane support rise is not physical contact-sensor evidence.
Validation and known limitations
JumpV3DetectorTests, JumpLocalFeatures and V3 condition source were inspected. No device or human jump was validated while writing this article. The current project record retains limitations around derivative availability at slower capture cadence and action readiness.