Rendered joint motion validation

The maintained trace protocol ships with the cad-motion-validation skill, including when the workflow installer copies the skill to a different machine. It documents the independent CAD reference, actual renderer capture, cad-agent motion-trace CLI, required coverage, diagnostics and evidence limits.

flowchart TD
    CAD["CAD source<br/>axes, landmarks"] --> Ref["reference<br/>home frame"]
    Scene["browser scene<br/>matrices × vertices"] --> Obs["observed<br/>trace"]
    Ref & Obs --> T["motion-trace<br/>compares each range"]
    G["motion gate<br/>interference"] -.->|"complements"| T
    T --> Rep["report<br/>coverage, diagnostics,<br/>input hashes"]
    classDef here fill:#fffdf5,stroke:#173d3c,color:#173d3c
    classDef near fill:#eef1e4,stroke:#6f8a80,color:#173d3c
    classDef out fill:#ffe1cc,stroke:#bd3a12,color:#173d3c
    class Ref,Obs,T here
    class CAD,Scene,G near
    class Rep out

Two independent paths meet only in the comparison: the reference comes from the CAD, the observation from the renderer that people actually look at, so a pivot error in either shows up.

A closed loop, such as a four-bar or a five-bar leg, is declared under loops on top of the joint tree. Its inputs are sampled together, its other joints are solved, and each sample's loop must close where the solver closes it. See the protocol, and Linkages for the solver.