Issue:
You have a CAD model created with Rhino, and you want to bring it into Inventor for further design or to build off of it.
Solution:
Autodesk has an add in for use with Inventor 2011, 2010, and 2009 on it's labs site (Inventor 2012 and beyond will include this translator without the need to download it).
http://labs.autodesk.com/utilities/rhino_import/overview/
