Quickstart

This walkthrough creates a mounting plate with a through bore, checks the resulting solid, and exports both an engineering STEP file and a browser-ready GLB preview.

Build the part

Create mounting_plate.py:

mounting_plate.py

import json
from pathlib import Path

import cadflow as cad


output = Path("output")
output.mkdir(exist_ok=True)

with cad.Model() as model:
    plate = model.box(80, 50, 8)

    bore = model.cylinder(radius=6, height=12)
    bore = model.translate(bore, 20, 25, -2)
    part = model.cut(plate, bore)

    report = part.validate()
    if not report.ok:
        raise RuntimeError(report.to_dict())

    print(json.dumps(part.describe(), indent=2))
    part.export_step(str(output / "mounting_plate.step"))
    part.export_stl(str(output / "mounting_plate.stl"))
    part.export_preview_glb(str(output / "mounting_plate.glb"))

Run it inside the environment where CadFlow is installed:

python mounting_plate.py
ls -lh output/

Understand the model lifetime

cad.Model() owns a native C++ session. Every Shape returned by that model is a lightweight handle into the session:

Model context
  └─ native Session
       ├─ plate handle
       ├─ bore handle
       └─ final part handle

Shapes from different models cannot be combined, and handles become invalid after the model closes. Keep construction, measurement, and export inside the with cad.Model() block.

Read structured geometry evidence

Shape.describe() returns JSON-safe values instead of formatted console text. A summary includes fields such as:

{
  "kind": "solid",
  "volume": 18904.42,
  "bbox": [0.0, 0.0, 0.0, 80.0, 50.0, 8.0],
  "topology": {
    "solids": 1,
    "faces": 7
  }
}

Exact counts and floating-point values depend on the resulting OCCT topology. Use report fields programmatically; do not parse display strings.

Validate before delivery

Shape.validate() checks the shape and returns an OperationReport. For delivery code, combine it with workflow-specific invariants:

report = part.validate()
if not report.ok:
    raise RuntimeError(report.to_dict())

if part.topology.get("solids") != 1:
    raise RuntimeError(f"expected one solid: {part.topology}")

if part.volume <= 0:
    raise RuntimeError("part has no positive volume")

This separates kernel validity from your engineering expectations.

Choose an output

Output	Method	Typical consumer
STEP	shape.export_step(path)	CAD systems and downstream manufacturing workflows
STL	shape.export_stl(path, binary=True)	Mesh-based fabrication and inspection tools
GLB	shape.export_preview_glb(path)	Browsers, web viewers, and agent run records
Mesh arrays	shape.mesh(deflection=0.1)	Custom renderers and numeric processing

Next steps

• Add profiles, features, and transforms in Modeling basics.
• Build constrained 2D geometry with Sketches and workplanes.
• Harden an artifact pipeline with Inspect, validate, and export.