Mechanical Engineer here and I design stuff in CAD for a living. OpenSCAD is great for the basic stuff but doesn't really scale well. It's fun to play with and to teach people programming and CAD at the same time. If FOSS is really a concern, FreeCAD is probably the better route.<p>However, like others said, Fusion 360 for hobbyist is the way to go. For professionals, just go with Solidworks. IMHO, it works better than anything (though I only also know and have been trained how to use Inventor, Creo, and NX so I do not know how other software like Catia will compare). Solidworks is way more advanced than Fusion 360 when you need to design something a bit more complex. Don't forget, CAD modeling is only half the work. Making good drawings is the other half and Fusion 360 drawing capabilities is pretty crappy as of right now.<p>As for the FOSS debate, it's quite interesting because no one in the industry cares about being locked in. $4000 for a license is nothing compared to "$140/hr" rate that engineers cost a company. As long as the software works and the engineer produces tangible results, closed source software will continue to dominate.