18. Identity continuity, quantities, coordinates, geometry, and scale
A universal system must survive serial-number changes, donor parts, replacement frames, stage separation, transforming geometry and contradictory measurements. Identity continuity is a governed decision; physical state is expressed with units, reference…
Concept & directionLNK
A universal system must survive serial-number changes, donor parts, replacement frames, stage separation, transforming geometry and contradictory measurements. Identity continuity is a governed decision; physical state is expressed with units, reference frames, uncertainty and time. Neither is safely represented by a mutable row of convenient values.
#18.1 Identity continuity decision record
| Field | Required content |
|---|---|
| Subjects | predecessor, candidate successor(s), donor assets, removed assemblies and legal records |
| Trigger | repair, rebuild, replacement shell/frame/hull/airframe, split, merge, stage separation, repurpose, recovery or replica discovery |
| Competing continuity bases | legal identity; manufacturer identity; load-bearing structure; functional continuity; community provenance; custody; digital/persona continuity |
| Policy | jurisdiction/domain/organization policy and version; mandatory versus advisory |
| Evidence | marks, documents, photographs, scans, material/forensic tests, work records, ownership chain and witness statements |
| Decision | same identity; successor identity; new identity; split identities; merged assembly only; indeterminate; disputed |
| Consequences | identifier mappings, meter/life inheritance, warranties, approvals, title, market history, persona, followers and disclosure |
| Review | decision maker, authority, date, confidence, dissent, appeal, supersession and public/private explanation |
#18.2 Difficult continuity cases
| Case | Default modeling stance | Must remain explicit |
|---|---|---|
| VIN/chassis plate replaced | Internal asset ID does not change automatically | Legal re-identification, plate custody, authority decision and fraud checks |
| Frame/hull/airframe replacement | Create before/after configurations and request continuity decision | Structural provenance, regulatory rule, donor identity and market disclosure |
| Restoration from many donors | Track every donor component and create or confirm root identity | What survived, what was reproduced, lineage uncertainty and authenticity claims |
| Rocket stage separation | Each stage may already be an asset; stack identity ends or changes | Membership, control, custody, consumed/recovered disposition and mission lineage |
| Vehicle split into two builds | One predecessor can produce several successor candidates | Which history and rights each successor inherits; no automatic duplication |
| Two wrecks merged | Do not silently pick the most valuable identity | Legal basis, dominant structure, donor history, disclosures and dispute state |
| Battery repurposed | Battery instance persists; role and passport responsibility change | Original and new passports, state-of-health, safety, custody and use history |
| Model or replica | Always a distinct physical identity | Represents relationship, scale/fidelity, licensed livery/persona and no inherited VIN/history |
| Persona transferred | Persona rights may move without moving physical identity | Canon, followers, likeness/license, old/new host disclosure and revenue rights |
| Digital twin fork | Create a new digital artifact lineage | Data cutoff, model assumptions, source asset and synchronization authority |
#18.3 QuantityValue contract
| Field | Rule |
|---|---|
| quantity_kind_ref | Stable semantic quantity such as torque, shaft power, displaced volume or remaining-energy estimate |
| value_shape | scalar; vector; matrix/tensor; interval; time series; distribution; categorical result |
| original_value + unit | Exact received representation, precision and source unit; never discarded after normalization |
| canonical_value + unit | Optional normalized value plus conversion-registry/version and rounding method |
| tolerance | Design/manufacturing/acceptance tolerance, distinct from measurement uncertainty |
| uncertainty | Standard/expanded uncertainty, confidence interval, covariance or declared unknown |
| reference_conditions | Temperature, pressure, density, humidity, fuel, state of charge, correction standard and load |
| frame + datum | Coordinate frame, origin, axes, handedness, datum, epoch and transform chain |
| method + instrument | Procedure/revision, sensor/instrument instance, range, resolution and calibration |
| time | Phenomenon/result time, duration, sample clock, time zone and synchronization quality |
| configuration | Exact as-measured/as-tested configuration, software, calibration, payload and control mode |
| quality | validity flags, saturation, dropout, interpolation, filtering, outlier treatment and reviewer |
| derivation | Formula/model, inputs, implementation version and uncertainty propagation |
#18.4 Coordinate-frame and transform graph
| Frame family | Required definition |
|---|---|
| Asset body | Root rigid-body frame; origin and orientation convention locked by design/configuration |
| Component local | Frame attached to a component occurrence or articulated link |
| Sensor / camera | Optical/acoustic/radar/instrument frame plus calibration and covariance |
| Tool / work target | End-effector, tool-center-point, workpiece or interaction frame |
| Payload / occupant | Mount, restraint, cargo, center-of-mass or seating reference frame |
| Route / track / guideway | Chainage, lane, rail, cable, pipe, tunnel or mission-path coordinate |
| Local map | Site/world frame with map version, origin and drift/alignment history |
| Geodetic | Latitude/longitude/height with datum, ellipsoid, geoid and epoch |
| Marine | Chart datum, waterline, depth-positive convention, tide/current reference |
| Aerospace inertial / Earth-fixed | Inertial and rotating frames, time standard and transform source |
| Orbital / celestial | Central body, reference plane, epoch, element/state representation and propagator |
- Transforms are first-class, time-varying records with source, calibration, interpolation, covariance and validity interval.
- A point without a frame is incomplete; altitude without a vertical datum is ambiguous; heading without north/reference convention is ambiguous.
- Articulated and deformable machines require joint states, constraints and a configuration-specific kinematic model rather than one static body frame.
- Privacy projections can transform or fuzz coordinates, but the transformation and disclosure policy must remain auditable.
#18.5 Geometry, envelope, mass properties, and scale
| Representation | Purpose | Key semantics |
|---|---|---|
| Nominal dimensions | Search, compatibility and regulation | Configuration/mode, reference points, tolerance, loaded/unloaded state |
| Bounding volume | Storage, route, transport and collision checks | Axis-aligned/oriented box, cylinder, hull or custom volume in a named frame |
| Detailed geometry | Design, scan, simulation and fabrication | Format/version, unit, frame, topology, level of detail, digest and rights |
| Swept volume | Turning, articulation, rotor/wing/tool motion and clearance | Joint/mode trajectory, safety margin and environment |
| Reach/work envelope | Manipulator, crane, tool, sensor and payload capability | Configuration, load, precision, exclusions and collision zones |
| Contact/support geometry | Tire patch, track, foot, hull, foil, wing, mooring or rail contact | Surface/medium, compliance, load distribution and state |
| Mass properties | Dynamics, balance, support and safety | Mass, CG/CB, inertia tensor, load case, consumables and uncertainty |
| Scale relationship | Model, replica and similarity | Reference design/asset, geometric/mass/time/force ratios and fidelity dimensions |
Scale is not one number
A 1:8 body can use non-scale tires, battery, motor, mass distribution, control latency or aerodynamic Reynolds regime. Record geometric, mass, kinematic, dynamic, control, appearance and mission fidelity independently, with the referenced design or asset.