An IGS file is a drawing that may contain either 2D or 3D vector graphics. It is saved in the Initial Graphics Exchange Specification (IGES) format, which uses plain text to represent wireframe models, surfaces, diagrams, and other objects.

The IGES format is a standard file format for transferring vector graphics between programs. Therefore, IGS (IGES) files can be imported and exported by many different CAD programs.

Important: The STEP (.STP) file format is now more common than the IGES format.