FreeCAD is an open source CAD application that has as its main objective the mechanical development and the industrial design.
This is aided by a modular design that allows too many configurations to be used in other applications.
FreeCAD is written in Python, and if you know Python you can extend it and automate many of the day-to-day tasks you do. The open source application can import and export many common file formats for 3D objects. Its modular architecture makes it very easy to extend its basic functionality with various plug-ins.
FreeCAD has many built-in options in its graphical environment. Let's sketch out the sketcher and renderer but also a robot simulation feature.
FreeCAD is actively deployed and the source code hosted on GitHub is available as an open source software under LGPL license.
Are you interested in the open source 3D application and want to read more? Visit her official webpage.
For now, the official page hosts the previous version, and you can download it for Windows, MacOS, and Linux.
However, developers just released the next version package, which you can download from here.