I use AutoCad 2014. And have an AutoCad 2013 3D .dwg file that when exported as a .stl file parts are missing. Does anyone have a solution. This was a first attempt by a client at 3D modeling. All I know to do is measure all the dimensions and remodel it in Inventor. He only used the default layer for everything. I exploded and deleted most of the file just to start gathering dimensions.