cq-acis

Parse ACIS SAT/SAB data and convert supported B-rep geometry to CadQuery/OpenCascade shapes.

日本語版: README.ja.md

This project is experimental. Supported geometry depends on the save version and producer. Unsupported entities remain available as raw records; conversion raises an error when it cannot build the requested shape within source precision. Projected 2D trims are checked against the unchanged 3D curves.

Features

• Read legacy and modern SAT headers, counted strings, and entity references.
• Decode SAT save versions 105, 400, 600, and 700, plus selected SAB and Autodesk ShapeManager binary profiles.
• Convert supported lines, circles, ellipses, planes, cylinders, cones, spheres, and tori, with experimental support for explicit NURBS and selected tolerant boundaries.
• Inspect topology, metadata, diagnostics, and the source data of unknown records.
• Use a shared model API to connect external decoders to the CadQuery converter.

See geometry support and limitations and SAB/ASM support for the accepted profiles.

Installation

Requires Python 3.11 or newer. CadQuery 2.8 or later is installed as a dependency.

python -m pip install cq-acis

Installing a prebuilt wheel does not require Rust. To install from a source checkout, install Rust 1.83 or newer and a C linker first, then run:

python -m pip install -e .

CadQuery's platform requirements also apply.

Quick start

Parse SAT records and follow topology references:

from pathlib import Path
from cq_acis import parse_sat_model

model = parse_sat_model(Path("model.sat").read_bytes())
for body in model.bodies():
    lump = model.resolve(body.lump)
    print(body.index, lump.index if lump else None)

Import a SAT file as a CadQuery Workplane:

from cq_acis import import_sat_file

result = import_sat_file("model.sat")
shape = result.val()
assert shape.isValid()
print(shape.Volume())

For binary SAB/ASM input:

from pathlib import Path
from cq_acis import parse_sab_model, to_cadquery

model = parse_sab_model(Path("model.sab").read_bytes(), source_id="model.sab")
print(model.diagnostics)
result = to_cadquery(model)

Parsing a file does not guarantee that all its geometry can be converted. See usage and error handling.

Documentation

• Documentation index
• Usage, export, and visual inspection
• Shared model API
• Geometry support and limitations
• SAB/ASM support and history limitations
• Tolerant boundaries and finite UV trims
• Rust APIs: acis-core, acis-py-bridge

The public API and supported format subset may change as coverage expands.

License

The project code is licensed under the MIT License. See third-party notices for dependency attribution. The repository's test corpus is excluded from the Python distributions and has separate license notices.