FreeCAD License Explained: Distribution and Use

FreeCAD is distributed under the GNU Lesser General Public License version 2 or later (LGPLv2+), which grants users the freedom to download, run, modify, and share the software for both private and commercial purposes. This article explains the core principles of the LGPLv2+ as applied to FreeCAD, covering what the license permits, user rights regarding created 3D models, obligations when modifying source code, and how third-party components affect usage.

The Primary License: LGPLv2+

The core application of FreeCAD is licensed under the GNU Lesser General Public License (LGPL). Specifically, it uses the "LGPLv2 or later" designation.

The LGPL is a free, open-source software license published by the Free Software Foundation. It is a weaker copyleft license compared to the standard GNU General Public License (GPL). While the standard GPL requires any program incorporating or linking to GPL code to also be released under the GPL, the LGPL allows proprietary or differently licensed programs to link to LGPL libraries without being forced to open-source the entire application.

User Rights and Commercial Use

Under the LGPLv2+, users of FreeCAD receive several fundamental freedoms:

  • Free of Charge: Anyone can download, install, and run FreeCAD without purchasing a license or paying subscription fees.
  • Commercial Applications: FreeCAD can be used freely for commercial purposes, including professional engineering, architectural modeling, and manufacturing.
  • Full File Ownership: The LGPL applies only to the software's code, not to the output generated by it. All 3D models, 2D technical drawings, exported G-code, and project files created using FreeCAD belong entirely to the creator. You are free to sell, license, or keep your design files proprietary.
  • Redistribution: You are permitted to redistribute identical copies of the FreeCAD installer, whether for free or for a fee.

Developer Obligations and Source Code Changes

The LGPL imposes specific requirements when changes are made to the FreeCAD software itself:

  • Modifying FreeCAD: If you modify FreeCAD's underlying source code and distribute that modified version to others, you must release your modifications under the LGPLv2+ as well. You must also provide access to the source code of those modifications.
  • Internal Use: If you modify FreeCAD for internal use within your company and never distribute the software externally, you are not obligated to share your changes with the public.
  • Developing Plugins and Workbenches: Because of the modular, LGPL-based architecture, external modules and Python scripts created for FreeCAD do not necessarily need to be open-source. Proprietary add-ons can interface with FreeCAD libraries provided they comply with standard LGPL dynamic linking terms.

Third-Party Libraries

While the FreeCAD core is LGPLv2+, the software integrates several external libraries that operate under their own open-source licenses:

  • Open CASCADE Technology (OCCT): The underlying geometric modeling kernel, licensed under the LGPL-compatible Open CASCADE Technology Public License.
  • Qt: The graphical user interface framework, primarily licensed under LGPL.
  • Python: The scripting engine, governed by the permissive Python Software Foundation (PSF) License.
  • Coin3D: The 3D visualization library, licensed under BSD-style terms.

All integrated components adhere to permissive or weak-copyleft licenses that maintain FreeCAD's status as fully functional, free, and open-source software for all users.