PRT (UG)
From Just Solve the File Format Problem
PRT is a format used by CAD/CAM software from Unigraphics (UG) or Siemens PLM (NX CAD). A number of other programs also have different-format files under the PRT name, so things can get confusing.
Sometimes these files are compressed, and this variety can be harder for other software to deal with.
KeyCreator and Spectrum can open these files of version 11 and up.
