An open source parametric 3D CAD modeler
FreeCAD is an open-source parametric 3D modeler made primarily to design real-life objects of any size. Parametric modeling allows you to easily modify your design by going back into your model history and changing its parameters. It is designed to fit a wide range of uses including product design, mechanical engineering, architecture and 3D printing.
FreeCAD allows you to sketch geometry constrained 2D shapes and use them as a base to build other objects. It contains many components to adjust dimensions or extract design details from 3D models to create high quality production-ready drawings. it is a multiplatfom (Windows, Mac and Linux), highly customizable using the Python language. It reads and writes to many open file formats such as STEP, IGES, STL, SVG, DXF, OBJ, IFC, DAE and many others, making it possible to seamlessly integrate it into your workflow.
FreeCAD includes a modern Finite Element Analysis (FEA) tools, experimental CFD, BIM, Geodata workbenches, a Path (CNC) workbench, a robot simulation module that allows you to study robot movements and many more, and a rich collection of plugins and macros installable directly from within the application.