what software would they need to open the iges format
- Save. IGES files are used by Computer Aided Design (CAD) programs. These files contain the designs of two-dimensional and three-dimensional drawings and models. According to the National Institute of Standards and Technology, the IGES format enables the CAD design to be transferred to unlike systems. Standard CAD software, such as Autodesk's AutoCAD can open these files, but if you only wish to view the file and little else, you can use a free viewer such IGS Viewer.