Third Party Tools
For every serious software development you need tools. Here is a list of tools we use to develop FreeCAD:
Platform independent tools
This is a great vector drawing program. It adheres to the SVG standard and is used to draw Icons and Pictures. Inkscape is Free and Open Source Software licensed under the GPL. Get it at www.inkscape.org.
A very good and stable tool to generate source documentation from the .h and .cpp files.
Not much to say about the GNU Image Manipulation Program. It can manipulate .xpm files which is a very convenient way to handle Icons in QT programs. XPM is basically C-Code which can be compiled into a program. Gimp supports the free .png file format used in the wiki.
Get the GIMP here: www.gimp.org
This is a proprietary git GUI that is very helpful to learn how git works if you're interested in wanting to contribute to FreeCAD. Relevant pages to research:
Free and open source software for video recording and live streaming. More details on official website : obsproject.com
OpenCamLib (OCL) is an open source library aiming to provide computer aided manufacturing (CAM) algorithms. FreeCAD uses OCL in the experimental 3D surface path operations and other experimental features.
A full featured but proprietary UML program. It has a lot of major features, including reverse engineering C++ source code.
Download here: staruml.io
Tools on Windows
Visual Studio Community
Visual Studio Community is free for open source projects and small structures. Installation is modular. You can add support for a large number of languages including C++ and Python.
It can be downloaded at 
Is an Open Source tool to record Screen-casts (Webcasts). It is a very good tool to create tutorials by recording them. Its far not so boring as writing documentation.
See camstudio.org for details.
Tools on Linux