build123d

Spec sheet

What it does

build123d is a Python-based parametric BREP modeling framework for 2D and 3D CAD built on the Open Cascade geometric kernel.Read 30 Sep 2026 · build123d.readthedocs.io

Free plan

YesRead 23 Sep 2026 · github.com

Support

The documentation points users to a Discord server shared with CadQuery for help in the build123d channel.Read 30 Sep 2026 · build123d.readthedocs.io

License

The project repository states that build123d is licensed under Apache License 2.0.Read 30 Sep 2026 · github.com

Algebraic Modeling

Supports operator-driven, readable, composable modeling logic.Read 28 Sep 2026 · build123d.readthedocs.io

Assembly design

YesRead 23 Sep 2026 · github.com

CAD Export

Models can be exported to FreeCAD and SolidWorks.Read 28 Sep 2026 · build123d.readthedocs.io

CAD interoperability

The project says models can be exported to tools such as FreeCAD and SolidWorks, and build123d objects can be exchanged with CadQuery through their shared OCP wrapper.Read 30 Sep 2026 · build123d.readthedocs.io

Cloud collaboration

NoRead 23 Sep 2026 · github.com

Code Standards

Uses PEP 8, mypy, pylint, and rich Pylance type hints.Read 28 Sep 2026 · build123d.readthedocs.io

Copyright Holder

The documentation shows copyright 2022, Gumyr.Read 28 Sep 2026 · build123d.readthedocs.io

Design Approach

Designed for modern, maintainable CAD-as-code.Read 28 Sep 2026 · build123d.readthedocs.io

Documentation Version

The page identifies the documentation as build123d 0.13.1.dev16+g66c62212d.Read 28 Sep 2026 · build123d.readthedocs.io

Extensibility

Custom objects and operations can be added as classes without monkey patching core functionality.Read 30 Sep 2026 · build123d.readthedocs.io

File import and export

Import: STEP, STL, 3MF; export: BREP, DXF, glTF, OBJ, STL, STEP, SVG, 3MFRead 23 Sep 2026 · github.com

Geometric Kernel

Built on the Open Cascade geometric kernel.Read 28 Sep 2026 · build123d.readthedocs.io

Geometry Basis

Boundary representation, or BREP, modeling.Read 28 Sep 2026 · build123d.readthedocs.io

Geometry Classes

Provides explicit 1D, 2D, and 3D geometry classes with defined operations.Read 28 Sep 2026 · build123d.readthedocs.io

Installation

The recommended installation for most users is `pip install build123d`, with development installation also available from GitHub.Read 30 Sep 2026 · build123d.readthedocs.io

Interchange formats

Documented import and export formats include 3MF, BREP, DXF, glTF, OBJ, STL, STEP, and SVG.Read 30 Sep 2026 · build123d.readthedocs.io

Manufacturing uses

The framework is intended for creating precise models for 3D printing, CNC machining, laser cutting, and other manufacturing processes.Read 30 Sep 2026 · build123d.readthedocs.io

Model Complexity

Intricate parametric models can be created in a few lines of readable Python code.Read 28 Sep 2026 · build123d.readthedocs.io

Modeling limitation

The docs warn that some parts cannot be constructed successfully by the underlying CAD core and that designers may need to try alternate approaches.Read 30 Sep 2026 · build123d.readthedocs.io

Modeling method

parametricRead 23 Sep 2026 · github.com

Modeling styles

It supports builder and algebra modeling modes, with operator-driven modeling and Python context managers.Read 30 Sep 2026 · build123d.readthedocs.io

Offline Documentation

Documentation is available in PDF and EPUB formats for offline reference.Read 28 Sep 2026 · build123d.readthedocs.io

Parametric design

The docs describe parameterized parts that can be modified by changing key variables and deriving related dimensions from them.Read 30 Sep 2026 · build123d.readthedocs.io

Product Type

Python-based parametric BREP modeling framework for 2D and 3D CAD.Read 28 Sep 2026 · build123d.readthedocs.io

Programming Language

PythonRead 28 Sep 2026 · build123d.readthedocs.io

Python Integration

Integrates deeply with Python through selectors, locations, and natural conversions.Read 28 Sep 2026 · build123d.readthedocs.io

Security and compliance

The pages reviewed provide no product-specific security certification or compliance claim.Read 30 Sep 2026 · build123d.readthedocs.io

Sheet-metal tools

YesRead 23 Sep 2026 · github.com

Support Channel

A Discord server shared with CadQuery provides a build123d help channel.Read 28 Sep 2026 · build123d.readthedocs.io

Supported operating systems

The installation instructions provide platform-specific commands for Windows and for Linux/macOS.Read 30 Sep 2026 · build123d.readthedocs.io

Supported platforms

Windows, macOS, Linux (Python package)Read 23 Sep 2026 · github.com

Surface modeling

YesRead 23 Sep 2026 · github.com

Viewer integration

The ocp-vscode viewer supports OCP-based code CAD, including CadQuery and build123d, inside VS Code.Read 30 Sep 2026 · build123d.readthedocs.io

Plans and prices

Every build123d plan and price →

Where Specifiction places it

• 3D CAD Software#20 of 798.3
• 3D modeling software#43 of 1478.4