What is a .iges file?
Initial Graphics Exchange Specification · 3D model · US National Bureau of Standards · 1980
An .iges (or .igs) file is a neutral CAD exchange format for moving precise engineering geometry, curves, surfaces and solids, between different CAD systems. It is one of the oldest and most widely supported CAD interchange formats.
What is a .iges file used for?
IGES is a plain-text format organised into fixed 80-column sections. It carries exact geometry rather than the triangle meshes of formats like STL, which matters for engineering.
It is being succeeded by STEP, which represents more of a model's design intent. Nearly every CAD tool imports IGES; open it in FreeCAD, SolidWorks, Fusion 360 or similar.
What opens a .iges file?
The .iges format opens in the following apps, grouped by operating system. If one app does not work, try another from the same list.
Windows
- FreeCAD
- SolidWorks
- Autodesk Fusion 360
macOS
- FreeCAD
- Autodesk Fusion 360
Linux
- FreeCAD
- OpenSCAD (via conversion)
Open a .iges file step by step
- Confirm the file really is a .iges. Drop it into the WhatFileType identifier, which reads its signature in your browser without uploading anything.
- On Windows, open it with FreeCAD or SolidWorks.
- On Mac, use FreeCAD or Autodesk Fusion 360.
- On Linux, try FreeCAD or OpenSCAD (via conversion).
- Still stuck? Convert the .iges to step, which opens more widely.
Why can't I open my .iges file?
Almost always because no installed app understands IGES. Install one of the apps above, or convert the file to a format your existing software already reads. If double-clicking opens the wrong program instead of nothing at all, the file association is set to the wrong app rather than the file being broken.
The other possibility is that the file is not really a .iges at all. Drop it into the file identifier to check it by its bytes instead of its name. Nothing is uploaded.
How to convert a .iges file
You can convert a .iges file to step, stl, obj using a conversion tool or the export menu of an app that opens it.
IGES has no fixed magic number, so there is no signature table on this page. Its bytes alone do not prove the format: identification relies on the extension, the structure of the content and the program that created it. The magic-numbers reference lists the formats that do carry one.
Frequently asked questions
What is a .iges file?
An .iges (or .igs) file is a neutral CAD exchange format for moving precise engineering geometry, curves, surfaces and solids, between different CAD systems. It is one of the oldest and most widely supported CAD interchange formats.
How do I open an IGES file?
Use a CAD program: FreeCAD is free and imports IGES, as do SolidWorks and Fusion 360. It is precise geometry, not a mesh.
What is the difference between IGES and STEP?
Both are neutral CAD exchange formats. STEP is newer and carries more design intent (assemblies, metadata); IGES is older but very widely supported.
Is .igs the same as .iges?
Yes. .igs and .iges are the same IGES format; the shorter extension is a historical three-letter version.
Related formats
Sources
Details on this page were checked against authoritative references. How sources are ranked and what is deliberately left out is set out in the methodology.