Does anyone have any CAD viewers they would recommend that can open NX, Catia, SolidWorks, and Autodesk Inventor files? All the software needs to be able to do is open the file and take simple measurements and volumes
Although not explicitly a viewer, I've heard impressive things about Autodesk Inventor's "AnyCAD" capability (which I think is a new feature as of the 2016 release). An internet search will yield much information about the new feature, although succinctly, it purports to allow Inventor to open and read native CAD data from a variety of platforms without an intermediate (e.g. step, iges) translation.
I work at a company using CATIA and Inventor. Although I'm on the Catia side, the Inventor folks speak very highly of the ability of Inventor (again, 2016 release) to successfully read in the native Catia data and use it for subsequent design.