How to convert files from Unigraphics
to IGES?

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.

IGES (Initial Graphics Exchange Specification) was among first vendor-neutral CAD formats designed to enable interoperability between different CAD systems. The latest versions of IGES have been approved by ANSI (American National Standards Institute) and published by US PRO (U.S. Product Data Association). The latest officially approved version of the IGES standard is version 5.3 which was published in 1996. Nonetheless, IGES remains a broadly used format (along with STEP) supported by all major CAD/CAM/CAE systems such as CATIA, Autodesk Inventor, Solidworks, Solid Edge, NX, Pro/Engineer, Creo and multiple others. IGES files usually have *.igs or *.iges file name extensions.