FreeCAD is a parametric 3D modeler made primarily to design real-life objects of any size. It is open-source and highly customizable.
Best build123d Alternatives ranked by AI · updated Aug 2026
build123d is an open-source Python-based framework for creating parametric 3D CAD models. It serves engineers, makers, and developers who want a modern code-first workflow with both builder and algebraic modeling styles.
Top 6 build123d alternatives
SolveSpace is a parametric 2D/3D CAD software that is free and open-source.
ImplicitCAD is an open-source, scriptable computer-aided design system built around implicit solid geometry and functional programming in Haskell. It is aimed at...
Pros
- Supports implicit geometry and constructive solid geometry in a functional language
- Generates models from reproducible source code rather than manual sketches
- Exports common formats including STL and SVG
Cons
- Smaller ecosystem and community than OpenSCAD or FreeCAD
- Requires Haskell knowledge for advanced modeling
- Fewer graphical modeling and inspection tools than full CAD suites
Free, open source
CadQuery is an open-source parametric 3D CAD python library.
5
OpenSCAD is a free software application for creating solid 3D CAD models.
Pros
- Script-based modeling
- Great for geometric designs
Cons
- Lacks interactive modeling features
6
OpenJSCAD
OpenJSCAD contributors
OpenJSCAD is an open-source, JavaScript-based solid modeling tool that runs in the browser or through command-line workflows. It is designed for web...
Pros
- Runs in a browser and uses familiar JavaScript
- Convenient for web-based demos, customization, and generated models
- Supports CSG and modular reusable geometry functions
Cons
- Less suited to traditional mechanical parametric modeling than CadQuery
- JavaScript toolchain setup can add complexity
- Smaller engineering ecosystem than FreeCAD
Free, open source
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