A file with .igs (Initial Graphics Exchange) extension is a 2D-3D design exchange file format that is independent of source or destination file format specifications used by CAD applications. It is be used to exchange design information about circuit diagrams, wireframe, freeform surface between two independent systems. It is similar to IGES and is primary requirement of manufacturers for pricing and designing molds for your product. IGS has most recently been replaced by the newer STEP(.STP) file format. IGS files can be opened by applications such as Autodesk, FreeCAD, CADEX CAD Exchanger and other similar applications.
IGS File Format
IGS files are in ASCII text file format and can be opened with any text editor. Each record in an IGS file is a 80-characters long. CAD applications save and export vector data in the IGS file format for transferring 3D model files between different software packages. Though IGS files can be opened in any text editor, the model or design can only be viewed by visualization applications that provide support for the IGS file format.