Format Guide
The original CAD exchange standard — still widely used for NURBS surfaces in aerospace and legacy workflows.
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| Extension | .igs, .iges |
|---|---|
| Full name | Initial Graphics Exchange Specification |
| Standard | ANSI Y14.26M |
| Geometry type | NURBS surfaces, curves, wireframe |
| Open standard | Yes |
| Supports color | Limited |
| Supports assemblies | Limited |
IGES (Initial Graphics Exchange Specification) was developed in 1980 and standardized as ANSI Y14.26M. It was the first widely adopted neutral format for exchanging 3D CAD data between different systems. IGES stores exact NURBS surfaces, curves, wireframe geometry, and basic annotations in a fixed-column ASCII text file. While STEP has largely superseded IGES for new workflows, IGES files remain in widespread use in aerospace, defense, and automotive — particularly at large organizations with legacy CAD archives spanning decades. Many older CAD systems only export IGES, not STEP.
Transfer geometry from older CAD systems that predate STEP support, or from archived projects that were saved in IGES format years ago.
IGES excels at representing NURBS surfaces used in automotive styling, aerospace panels, and industrial design where surface quality and curvature continuity matter.
Defense contractors often mandate IGES delivery for drawing interchange per military standards. Many supplier qualification pipelines still specify IGES.
SolidWorks, CATIA, Siemens NX, PTC Creo, AutoCAD, Rhino, ICEM Surf, FreeCAD, and most CAD/CAM systems manufactured since the 1990s.
Commonly converted to STEP for modern CAD exchange, to STL for 3D printing or CNC toolpath generation, or to OBJ for visualization.