Description
Subtract a supplied three-dimensional origin from a marker coordinate.
Movement geometry depends on coordinate registration, time origins, force signs and reference axes. A moment arm must already represent perpendicular leverage, a stride percentage has an endpoint convention, and a toe-to-heel projection differs from full Euclidean separation. Scalar results do not establish a movement diagnosis or a safe activity.
Subtract a supplied three-dimensional origin from a marker coordinate.
When to use this tool
Use Marker Segment Relative Coordinate when you already have marker, origin and need to subtract a supplied three-dimensional origin from a marker coordinate.
How to use the tool and how it works
- Enter marker, origin. Follow any array-alignment requirements below. Use the units and conventions below.
- Run the tool. Correct any format, range, or cross-field input error before interpreting the output.
- Read relative. Use the output convention below.
Require both arrays length three; return componentwise marker-origin.1
| Input field | Meaning and units | Accepted input |
|---|---|---|
| marker | Marker | Required. Array of finite number; maximum items 256. |
| origin | Origin | Required. Array of finite number; maximum items 256. |
| Output field | Interpretation | Returned shape |
|---|---|---|
| relative | Exactly three marker-origin components; translation only, without rotation. | Required. Array of finite number; maximum items 256. |
{
"input": {
"marker": [
10,
20,
30
],
"origin": [
2,
5,
10
]
},
"output": {
"relative": [
8,
15,
20
]
}
}Limitations and assumptions
- No axis rotation, coordinate-frame calibration, units, tracking, anatomical frame or physical motion is inferred.
- Inputs must satisfy both the field types and the cross-field conditions above. Invalid input causes an error; a successful false flag or documented placeholder is a different result.
- Numeric calculations use binary floating point unless exact decimal-integer arithmetic is explicitly stated. No hidden measurement tolerance or decimal rounding is added; nonfinite or out-of-contract results are rejected. Numeric signed-zero results are exported as zero.
Alternative or Complementary methods
Use calibrated motion, force and timing records with a complete biomechanical model. Check coordinate frames, axis normalization and sampling limitations before interpreting local distances, moments or phase values as performance or clinical findings.
References
Similar or alternative tools
- Motion Marker Rigid Segment Length Residual
Compare supplied marker-pair distance with a reference segment length.
- Gait Toe Heel Distance Projection
Project supplied heel-to-toe displacement onto an almost-unit forward axis.