Draftsight 2017 is out there at
www.draftsight.com It's pretty much a lookalike/workalike for Autocad 2013. If you're already familiar with Autocad there's no learning curve. There are good tutorials on that site also.
A simple 3D parametric modeler is Solvespace (
www.solvespace.com) It's a single executable file that doesn't require installation. It looks like something out of the '90s but works. Good tutorials there also, and the author hangs around the forum.