FreeCAD is a free and open-source (under the LGPLv2+ license) general-purpose parametric 3D CAD modeler. FreeCAD is aimed directly at mechanical engineering and product design but also fits in a wider range of uses around engineering, such as architecture or other engineering specialities. FreeCAD is currently in a beta stage of development.
FreeCAD features tools similar to CATIA, Creo, Autodesk Inventor, SolidWorks or Solid Edge, and therefore also falls into the category of Mechanical computer-aided design (MCAD), PLM, CAx and CAE. It is intended to be a feature-based parametric modeler with a modular software architecture, which makes it easy to provide additional functionality without modifying the core system.
As with many modern 3D CAD modelers, it will have a 2D component in order to extract design details from the 3D model to create 2D production drawings, but direct 2D drawing (like AutoCAD LT) is not the focus, neither are animation (like Blender) or organic shapes (like Maya, 3ds Max or Cinema 4D), although, thanks to its wide adaptability, FreeCAD might become useful in a much broader area than its current focus.
FreeCAD is intended to make use of other open-source libraries from the field of scientific computing. Among them are Open CASCADE (a CAD kernel), Coin3D (an incarnation of Open Inventor), the Qt GUI framework, and Python, a popular scripting language. FreeCAD itself can also be used as a library by other programs.
There are moves to take FreeCAD into the architecture, engineering and construction (AEC) sector and add building information modeling (BIM) functionality with the Arch Module.
Supported file formats
Freecad’s own main file format is FreeCAD Standard file format (.FCStd). It is a standard zip file, that holds files in certain structure. Document.xml file has all geometric and parametric objects definitions. GuiDocument.xml then has visual representation details of objects. Other files include brep-files for objects and thumbnail of drawing.
Besides FreeCAD’s own file format, files could be exchanged by the following file formats: DXF, SVG (Scalable Vector Graphics), STEP, IGES, STL (STereoLithography), OBJ (Wavefront), DAE (Collada), SCAD (OpenSCAD), IV (Inventor) and IFC.
FreeCAD’s support for the important DWG file format has been problematic due to software license compatibility problems with the GNU LibreDWG library. The GNU LibreDWG library started as a real open-source alternative to the source-available OpenDWG library (the later Teigha Converter) and is licensed under the GPLv3. As FreeCAD (and also LibreCAD) has dependencies on Open Cascade, which prior to version 6.7.0 was only compatible with GPLv2, it couldn’t use the GNU LibreDWG library as GPLv2 and GPLv3 are essentially incompatible. Open CASCADE technologies were contacted by Debian team in 2009, and 2012 got a reply that Open CASCADE technologies was considering dual-licensing OCCT (the library), however they postponed that move. A request also went to the FSF to relicense GNU LibreDWG as GPLv2 or LGPLv3, which was rejected too.