GrabCAD and FreeCAD, a marriage in Heaven?
From the FreeCAD Wiki: FreeCAD is a general purpose, multi-platform 3D CAD modeler. It is free software (GPL & LGPL License). 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 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 detail 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.
I've been using FreeCAD to design some 3D-printed parts for a project my wife needs for her research. The documentation is not great, as is typical for free / OSS software, but there tends to be several ways to accomplish what you want to do. Love being able to freely mix units and type measurements in directly.
I have filed an Atlas 10 inch Lathe created on FreeCAD on the GrabCAD site. FreeCAD has its own format, but to create assemblies on 15, 16, versions a piece part is either part of a single model, copied and pasted on to a separate model, and or converted to a step model and then put into an assembly of step parts. This is the approach I used for the lathe. However, the assembly is the FreeCAD format. These detail parts were sent individually to GrabCAD in step format. Could have sent to GrabCAD in FreeCAD format but last year that did not seem to be supported. So to create an assembly of step file components using the open to the public version of OnShape From this platform I could create an assembly step file.