.IGS File Extension

2 file types use the .igs file extension.
File Type 1

IGES Drawing

Developer ICAM
3.7  |  51 Votes
Category CAD Files
Format Text

What is an IGS file?

An IGS file is a graphics file saved in a 2D/3D vector format based on the Initial Graphics Exchange Specification (IGES), a standard ASCII text-based format. It stores wireframe models, surface or solid object representations, circuit diagrams, and other objects. Many CAD applications save and export vector data as IGS files.

More Information
Screenshot of a .igs file in CADEX CAD Exchanger 3.7
IGS file open in CADEX CAD Exchanger 3.7

IGES is a standard for transferring three-dimensional models between CAD programs. You will most likely encounter an IGS file only if you work with CAD software in a field that involves manufacturing, such as the automotive or aerospace industries.

The Integrated Computer-Aided Manufacturing (ICAM) United States Air Force department developed the IGES format in 1980. Many CAD programs subsequently adopted it, and it became a standard. However, in the mid-1990s, the STEP (.STP) format replaced the IGES format, and the usage of IGS files eventually declined.

NOTE: IGS files may also be saved with the .iges file extension (.IGES files).

How to open an IGS file

You can open IGS files with various desktop CAD programs, such as Autodesk Fusion 360 (Windows), Dassault Systemes CATIA (multiplatform), Nemetschek VectorWorks (multiplatform), and CADEX CAD Exchanger (macOS). You can also open and view IGS files with online viewers by uploading them to CADEX CAD Exchanger Cloud or ShareCAD.org.

Since IGS files store plain text information, you can open them with a text editor (you may need to change the .igs file extension to .txt). However, when viewing the files with a text editor, the contents will appear as text instead of a visual representation of a model, like when you view them with CAD software. You can use text editors, such as Microsoft Wordpad (bundled with Windows) or Apple TextEdit (bundled with macOS), to view the plain text in IGS files.

How to convert an IGS file

Various CAD applications, including CADEX CAD Exchanger, Autodesk Fusion 360, and Dassault Systemes CATIA, can convert IGS files to other formats.

For example, CAD Exchanger can convert IGS files to the following formats:

  • .STP, .STEP - STEP 3D Model
  • .SAT - ACIS SAT 3D Model
  • .STL - Stereolithography File
  • .BREP - BRep 3D Model
  • .JT - JT Open CAD File
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Programs that open IGS files

Updated May 11, 2022
File Type 2

Indigo Renderer Scene File

Developer Glare Technologies
3.3  |  19 Votes
Category 3D Image Files
Format N/A

What is an IGS file?

3D scene used by Indigo Renderer, an application used for generating photorealistic images; often saved as an export from another 3D modeling package that has the Indigo Renderer plug-in, including Blender, 3ds Max, Cinema 4D, Maya, SketchUp, or Revit.

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Once a 3D scene has been imported into Indigo Renderer, it can be rendered into a final image. The software supports GPU acceleration so that images can be generated more quickly.

Programs that open IGS files

Updated July 19, 2012

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