[](https://build123d.readthedocs.io/en/latest/?badge=latest) [](https://github.com/gumyr/build123d/actions/workflows/test.yml) [](https://github.com/gumyr/build123d/actions/workflows/lint.yml) [](https://github.com/gumyr/build123d/actions/workflows/mypy.yml) [](https://codecov.io/gh/gumyr/build123d)  [](https://github.com/psf/black) [](https://opensource.org/licenses/Apache-2.0) [](https://pypi.org/project/build123d/) [](https://pepy.tech/project/build123d) [](https://pepy.tech/project/build123d) [](https://pypi.org/project/build123d/) [](https://doi.org/10.5281/zenodo.14872322) Build123d is a Python-based, parametric [boundary representation (BREP)][BREP] modeling framework for 2D and 3D CAD. Built on the [Open Cascade] geometric kernel, it provides a clean, fully Pythonic interface for creating precise models suitable for 3D printing, CNC machining, laser cutting, and other manufacturing processes. Models can be exported to popular CAD tools such as [FreeCAD] and SolidWorks. Designed for modern, maintainable CAD-as-code, build123d combines clear architecture with expressive, algebraic modeling. It offers: - Minimal or no internal state depending on mode, - Explicit 1D, 2D, and 3D geometry classes with well-defined operations, - Extensibility through subclassing and functional composition—no monkey patching, - Standards-compliant code (PEP 8, mypy, pylint) with rich pylance type hints, - Deep Python integration—selectors as lists, locations as iterables, and natural conversions (Solid(shell), tuple(Vector)), - Operator-driven modeling (obj += sub_obj, Plane.XZ * Pos(X=5) * Rectangle(1, 1)) for algebraic, readable, and composable design logic. The result is a framework that feels native to Python while providing the full power of OpenCascade geometry underneath. The documentation for **build123d** can be found at [readthedocs](https://build123d.readthedocs.io/en/latest/index.html). There is a [***Discord***](https://discord.com/invite/Bj9AQPsCfx) server (shared with [CadQuery]) where you can ask for help in the build123d channel. The recommended method for most users to install **build123d** is: ``` pip install build123d ``` To get the latest non-released version of **build123d** one can install from GitHub using one of the following two commands: Linux/MacOS: ``` python3 -m pip install git+https://github.com/gumyr/build123d ``` Windows: ``` python -m pip install git+https://github.com/gumyr/build123d ``` If you receive errors about conflicting dependencies, you can retry the installation after having upgraded pip to the latest version with the following command: ``` python3 -m pip install --upgrade pip ``` Development install: ``` git clone https://github.com/gumyr/build123d.git cd build123d python3 -m pip install -e . ``` Further installation instructions are available (e.g. Poetry) see the [installation section on readthedocs](https://build123d.readthedocs.io/en/latest/installation.html). Attribution: Build123d was originally derived from portions of the [CadQuery] codebase but has since been extensively refactored and restructured into an independent system. [BREP]: https://en.wikipedia.org/wiki/Boundary_representation [CadQuery]: https://cadquery.readthedocs.io/en/latest/index.html [FreeCAD]: https://www.freecad.org/ [Open Cascade]: https://dev.opencascade.org/