 
 MEDIUM
 MEDIUM |  |  | |
| Name | NX Part/Assembly File | Initial Graphics Exchange Specification | 
| File extension | .prt | .igs, .iges | 
| Original software | NX (Unigraphics) | |
| Binary | ■ | |
| ASCII | ■ | |
| Polygonal | ■ | |
| NURBS | ■ | ■ | 
| Solids | ■ | |
| Smoothing groups | ■ | ■ | 
| Textures, materials | ■ | |
| Developer/Owner | Siemens | U.S. National Bureau of Standards | 
| Description | ||
| Specification | Download PDF | |
| Format features | Universal open interchange NURBS-surfaces format. Along with STEP - one of the most popular | |
| Viewing software | Delcam Exchange 2012 (free) | Delcam Exchange 2012 (free), eDrawings (free) |