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FreeCAD Developers Handbook

A handbook about FreeCAD development

Getting Started #

Covers how to set up a build environment for contributing to FreeCAD

Working on FreeCAD is similar to working on may other open-source projects. This guide provides a short overview of the process. Much more information can be found at

Build Environment #

To work on FreeCAD you will need CMake, git, a code editor, a C++ compiler, and a Python interpreter. Many different combinations work:

Other combinations may work as well, these are just the ones that you will be able to get help with most readily on the FreeCAD Forum.

Dependencies #

See also Dependencies

FreeCAD depends on many other open source projects to provide the basic foundations of the program. There are many ways of installing these dependencies: for details and the complete list, see the following Wiki pages:

Setting up for Development #

  1. Fork on GitHub
  2. Clone your fork: for example, on the command line you can use git clone FreeCAD-src
  3. Set up pre-commit (our automatic code-formatter and checker):

    • Install pre-commit (either using your system package manager or pip):
      • Debian/Ubuntu: apt install pre-commit
      • Fedora: dnf install pre-commit (Fedora)
      • Arch Linux: pacman -S pre-commit
      • Other (pip in PATH): pip install pre-commit
      • Other (pip not in PATH): python -m pip install pre-commit
    • On a command line, change into your FreeCAD clone, e.g. cd FreeCAD-src
    • Run pre-commit install (or python -m pre-commit install, depending on your PATH)
  4. We strongly recommend doing an out-of-source build, that is, build FreeCAD and put all generated files in a separate directory. Otherwise, the build files will be spread all over the source code and it will be much harder to sort out one from the other. A build directory can be created outside the FreeCAD source folder or inside:

    • mkdir build
    • cd build
  5. Run CMake, either in via the CMake GUI or on the command line see the wiki compilation page for your operating system for a detailed list of options.
  6. CMake will generate project files that can be read by your IDE of choice. See your IDE’s documentation for details. In general:

    • On Linux, compile with a command like cmake --build /path/to/FreeCAD-src run from your build directory ( or cmake --build .. if your build directory is inside FreeCAD-src).
    • On Windows with Visual Studio, build the “ALL_BUILD target” (you will have to change the path to the final executable the first time you try to run that target).
    • On Mac on the command line use cmake --build /path/to/FreeCAD-src from your build directory, or if using CLion be sure to “Build All” the first time you run.
  7. If you plan on submitting a PR, create a branch:

    • git branch fixTheThing
    • git checkout fixTheThing (or both commands in one go: git checkout -b fixTheThing)

Submitting a PR #

The basic process is:

  1. Write some code (and possibly some unit tests)
  2. git add file1.cpp file2.cpp
  3. git commit -m "Sketcher: Fixed bug in constraints" -m "Added foo to bar. Fixes #1234."
    • When running git commit our pre-commit hooks will run to check your code. If the scripts had to make changes, you will have to git add the changed files and run git commit again.
  4. git push to send your changes to GitHub
  5. Visit – at the top of the screen you should see a yellow banner suggesting you create a Pull Request. Follow the instructions on the site to get the process started.