FreeCAD is an open-source parametric 3D modeler made primarily to design real-life objects of any size. 

FreeCAD is a multiplatfom (Windows, Mac and Linux), highly customizable and extensible software.

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.