Jerry
96 lines
2.8 KiB
Markdown
96 lines
2.8 KiB
Markdown
# Per-part model specification
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Use one `model-spec.json` per generated or imported part. Treat it as the
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editable geometry contract. Keep `cad-task.json` separate for routing,
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experience use, validation results, and viewer links.
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## Native generator
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Use `native_generator` when the part has editable Python source:
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```json
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{
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"schema_version": "1.0",
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"model_spec_kind": "parametric_cad_model",
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"model_id": "example_part",
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"units": "mm",
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"reconstruction": {
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"mode": "native_generator",
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"generator": {
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"path": "example_part.py",
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"entrypoint": "gen_step"
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}
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},
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"parameters": {
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"width": {
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"value": 40,
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"unit": "mm",
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"role": "overall_width"
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}
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},
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"modifications": [],
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"outputs": {
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"step": "example_part.step",
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"stl": "example_part.stl"
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}
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}
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```
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The generator must read its sibling `model-spec.json`. Do not duplicate
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authoritative parameter values as editable constants in both files.
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## Imported STEP
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Convert an explicitly supplied STEP into a task-local exact-base specification:
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```bash
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python scripts/model_spec.py import-step input.step \
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--task-dir models/cad-router-v1/imported_part \
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--model-id imported_part
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```
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This copies the source to `source.step`, records its SHA-256 and geometry
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signature, writes `model-spec.json`, and exports regenerated STEP/STL files.
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With an empty modification list, `verify` requires the imported B-Rep to retain
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the same bounds, center, topology counts, solid count, and volume.
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STEP normally contains final B-Rep geometry, not the original sketches,
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constraints, names, or feature history. Therefore:
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- `exact_step_base` guarantees an unchanged imported base, not recovered native
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design history.
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- Add later edits as named parametric modifications.
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- Use semantic native reconstruction only when the feature family can be
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reliably recognized and validate it independently against the source.
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- Never claim arbitrary STEP-to-JSON conversion recovers the author’s original
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parameters or construction order.
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## Parametric modification layer
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Supported V1 operations are `add_box`, `cut_box`, `add_cylinder`, and
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`cut_cylinder`. Values may be literals or parameter references:
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```json
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{
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"id": "central_bore",
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"operation": "cut_cylinder",
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"axis": "z",
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"center": [0, 0, 0],
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"diameter": {"parameter": "bore_diameter"},
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"length": {"parameter": "bore_length"},
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"enabled": true
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}
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```
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Change a named value and rebuild:
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```bash
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python scripts/model_spec.py set path/to/model-spec.json bore_diameter 18
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python scripts/model_spec.py build path/to/model-spec.json
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python scripts/model_spec.py verify path/to/model-spec.json
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```
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Use `apply_patch` when adding or structurally editing parameters and features so
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the modification remains reviewable. After every visible rebuild, run the CAD
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inspection and snapshot workflow and update `cad-task.json`.
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