yhz5613813/cadflow/cadflow-model-part

CadFlow Part Modeling

Build one reproducible mechanical part at a time. Use import cadflow as cad and the public Python frontend. Read references/public-api.md when a signature or operation boundary matters.

Select the modeling boundary

• Use cad.Model() and cad.Shape for the current session-oriented frontend

when writing ordinary part scripts.

• Use GraphSession, @cad.model, cad.capture_result(), and the

make_*_r* APIs when the result must be replayed through model JSON.

• Do not mix shapes created by different sessions.
• Do not import cadflow._engine, OCP/CadQuery classes, native handles, or

private shared-library symbols in a part script.

• For FEA surfaces, face contact, friction, coatings, or solver handoff, finish

the geometry here and then use cadflow-contact-simulation.

Required workflow

1. Extract units, dimensions, tolerances, datums, feature order, placement,

and requested output files. State assumptions when the specification is incomplete.

1. Choose and document the coordinate frame. Keep all dimensions in one unit;

convert at the input boundary rather than mixing units in operations.

1. Build named intermediate values in feature order: base, additive features,

subtractive tools, transforms, then finishing operations.

1. Use sketches for dimensioned planar profiles. Promote a solved sketch to a

wire/face before extrusion, revolution, or a profile cut.

1. After the base, every boolean, and each fillet/chamfer/shell, query a

diagnostic. Check overlap and tool extent for through cuts.

1. Validate the final shape: validity, solid count, volume, area, bounding-box

extents, and the topology needed by the request. Compare against stated tolerances, not visual intuition.

1. Export only after validation. Create the output directory, write requested

STEP/STL/PNG/JSON files, and verify existence and non-zero size.

1. Leave the generation script and report exact assumptions, commands,

measurements, and output paths.

Modeling rules

• Treat operations as functional: retain useful source values instead of

overwriting every feature.

• Keep a requested single part as one Solid; never hide a failed boolean by

returning an arbitrary component of a compound.

• Query faces/edges before indexed fillet, chamfer, or shell selections.

Topology indices can change after any topology-changing operation.

• Apply repeated holes or pockets sequentially unless fused tools are known to

overlap and the fused tool has been validated.

• Use positive, finite dimensions and reject impossible radii before invoking

a kernel operation.

• Keep graph recording and export parameters faithful. Do not claim replay

equivalence when only a preview was checked.

Minimal current-frontend pattern

from pathlib import Path
import cadflow as cad
out = Path("outputs/bracket")
with cad.Model() as model:
    base = model.box(width=20.0, depth=30.0, height=10.0)
    tool = model.cylinder(radius=3.0, height=14.0)
    tool = model.translate(tool, x=10.0, y=15.0, z=-2.0)
    final_part = model.cut(base, tool)
    print(final_part.describe())
    print(final_part.validate().to_dict())
    print(final_part.bbox, final_part.volume, final_part.topology)
    out.mkdir(parents=True, exist_ok=True)
    final_part.export_step(str(out / "bracket.step"))
    final_part.export_stl(str(out / "bracket.stl"), binary=True)

For replayable workflows, see references/public-api.md for the GraphSession/@cad.model pattern.

Failure handling

• A native-library error is an environment/build issue until geometry checks

prove otherwise. Report the exact command and error; do not bypass it with private imports.

• For a failed boolean, inspect body/tool bounds, overlap, orientation, and

validity before changing dimensions.

• For a failed feature, reduce the selection and radius only as a documented

diagnostic experiment; do not silently weaken the requested geometry.

• If the specification is underdetermined, state the chosen assumption and

expose it as a parameter in the script.