Reverse Engineering Workflow
FreeCAD
How to take models such as https://hw.menardc.com/main/items/media/DOLPH001/Prod_Tech_Spec/6704580dimension.pdf and reproduce them readily in FreeCAD. It is easiest to import the drawing into FreeCAD, set scale to be accurate, and then trace over the lines in the image. That is a great first-approximation for accurate design.
FreeCAD Architecture
You can use DWG format import to work from. See example by Yorik - https://wiki.freecadweb.org/Arch_tutorial
SweetHome 3D
Taking an imported blueprint, and re-creating it in SweetHome3D - http://www.sweethome3d.com/userGuide.jsp#importingHomeBlueprint