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 used to exchange design information about circuit diagrams, wireframes, the freeform surfaces between two independent systems. IGS files can be opened by applications such as Autodesk, FreeCAD, CADEX CAD Exchanger, and other similar applications.
Files with XLTX extension represent Microsoft Excel Template files that are based on the Office OpenXML file format specifications. It is used to create a standard template file that can be utilized to generate XLSX files that exhibit the same settings as specified in the XLTX file.
You can also convert IGS into many other file formats. Please see the complete list below.