Some notes on using "FreeCAD". It can open and manipulate STEP files (and probably many other things). These notes apply to version 0.18.1.

Making a 2D drawing from part of a model

• Use the new TechDraw? workbench module:
  • Wiki: ​https://www.freecadweb.org/wiki/TechDraw_Module
  • Tutorial: ​https://www.freecadweb.org/wiki/Basic_TechDraw_Tutorial

Tip: to open a new workbench, click on the "mode" thingy: