On a day to day basis on the support Help desk at Microconcepts we get a fair few people asking how they can transfer or save their Inventor files in older versions of software. For example using Inventor 2013 and you need to open the drawing in AutoCAD 2012.
From the Inventor idw, we can go to 'Save Copy As' via the 'Save As' tool in the Inventor home button. Now making sure you've selected the correct file format. If you move the cursor over to 'Options' on the bottom right hand corner of the 'Save Copy As' window and left click.
Within Options you will be presented with pull down box options. Select the box under file 'File Version' in here you can select the software format you need that pre-dates the Software you are running.