how do you convert an ipt file into a dwg file

You can't convert an .ipt file to a .dwg file.  The best you can do, while in Inventor, is use the "Save Copy As" option and save to a file format that can either be opened directly (ex. - .dwg or .dxf) or imported.And why did you post your question re: Inventor and AutoCAD in the Civil3D forum?
John Connor2016-08-12 19:24:02