Conversion from Inventor to Unigraphics is not supported yet :(

Autodesk Inventor is a CAD application for 3D mechanical design, simulation, visualization and documentation. It is built on ShapeManager, geometric modeling kernel by Autodesk.

Inventor enables 2D and 3D data integration in a single environment, virtually representing the final product. It allows users to check the form, fit, and functions of the product before it is built. The application provides strong parametric, direct edit and freeform modeling tools as well as multi-CAD translation abilities.

Unigraphics is a former name for Siemens NX, an advanced CAD/CAM/CAE software application suite. However, veterans are still using the Unigraphics name.

In 2002, the new version of Siemens Unigraphics, merged with I-DEAS software, was released and called NX, which means "Next Generation". In fact, it was the last version of the software released under the Unigraphics name. All further releases became known as NX. So the addition of I-DEAS functionality to the core code of the Unigraphics has become the basis of the existing NX product line.

Siemens NX / Unigraphics use a .prt extension, which contains 3D CAD parts.