# Parameter architecture

    **Skill ID:** `parametric_cad.parameter-architecture`  
    **Domain:** Parametric CAD  
    **Initial status:** Reading only; not certified for Forge.

    ## Purpose

    Teach SHiRE to apply **Parameter architecture** as one part of a complete design workflow. This skill must be combined with requirements, safety, research, manufacturing and validation rather than used alone.

    ## Learning outcomes

    SHiRE must be able to:

    1. Explain when this skill is appropriate.
    2. Identify required inputs and missing evidence.
    3. Choose a repeatable, editable method.
    4. Detect likely failures.
    5. Define measurable acceptance criteria.
    6. preserve source provenance and licence status.
    7. Refuse, constrain or escalate unsafe use.

    ## Domain principles

    - Name parameters by meaning and include units, ranges and dependencies.
- Build from stable datums instead of fragile generated edges.
- Separate user parameters from derived calculations.
- Test parameter families at boundaries and invalid combinations.
- Release editable source plus neutral STEP after validation.

    ## Repeatable method

    1. Preserve the original dialog.
    2. Extract purpose, interfaces, dimensions, tolerances, environment and risk.
    3. Mark facts, measurements, retrieved evidence and assumptions separately.
    4. Search official and clearly licensed sources for current principles.
    5. Create a small safe practice example.
    6. Preserve editable source and named parameters.
    7. Test minimum, nominal, maximum and invalid cases.
    8. Record pass, fail, limitation and evidence paths.
    9. Keep Forge permission false until Academy certification passes.

    ## Common failures

    - Scattered hard-coded dimensions.
- Circular dependencies.
- Fragile topological references.
- A model that only works at nominal values.
- STL-only release.

    ## Practice exercises

    - Explain the skill through a safe household example.
    - Build a deliberately wrong example and diagnose it.
    - Build a parameterised example across minimum, nominal and maximum values.
    - Create a provenance record for every source.
    - Apply the skill in a multi-domain brief without bypassing safety.

    ## Certification

    - knowledge score at least 90 percent;
    - three completed practice projects;
    - one rejected example correctly diagnosed;
    - boundary and invalid tests;
    - provenance and licence review;
    - safety gate;
    - editable source and validation report;
    - no hidden blockers.

    ## Limitations

    This starter lesson defines a learning and evidence framework. It does not replace current standards, calibrated machine profiles, verified material data, physical testing or qualified professional review.