What program do you use for the 3D views? It might give me a better idea of how this is all supposed to fit together.
Made in inventor 2015, exported to AutoCAD 2015 3D model. You should be able to open it in any CAD program version 2015 and higher (even freeware ones), or you can download for free Autodesk View 2015 (or 2016), which is only viewer.