The .IGS file extension stands for IGES drawing file. This is a special type of 2D/3D vector graphic file which is based on the Initial Graphics Exchange Specification. This file is not vendor specific and thus allows more software to put it as their standard output format for the 2D and 3D models.

The file structure is based on the ASCII text-based format and is used in many CAD programs for delivering high end graphics. The file allows the data in vector format and also gives support for wireframe drawings. This format is slowly becoming obsolete.