.STEP File Extension

STEP 3D Model

Developer International Organization for Standardization
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What is an STEP file?

A STEP file is a 3D model file formatted in STEP (Standard for the Exchange of Product Data), an ISO standard exchange format. It contains three-dimensional model data saved in a text format recognized by multiple computer-assisted design (CAD) programs.

More Information

Screenshot of a .step file in Autodesk Fusion 360 2.0
STEP file open in Autodesk Fusion 360 2.0

The International Organization for Standardization (ISO) developed the STEP format to make it easier to share models between users with different CAD systems in the CAD industry. Since its release in 1994, STEP has become a standardized, widely-supported format that CAD users can use to save and transfer models between users and programs.

While STEP files appear as 3D models in CAD programs, they consist of plain text that describes a model's structure. The text that STEP files contain is written in an ASCII format that conforms to the STEP Application Protocols ISO 10303-2xx.

NOTE: STEP model files often use the .STP file extension.

How to open an STEP file

You can open a STEP file in a variety of CAD programs, including Autodesk Fusion 360 (cross-platform), IMSI TurboCAD (Windows, Mac), FreeCAD (cross-platform), and Dassault Systemes CATIA (Windows, Linux).

For example, to open a STEP file in Autodesk Fusion 360:

  1. Select File → Open... from the program's menu bar
  2. When the Open window appears, select Open from my computer...
  3. Navigate to and open your STEP file

Opening an STEP file with a text editor

STEP file open in Microsoft Notepad
STEP file open in Microsoft Notepad

Since STEP files are saved in plain text, you can open a STEP file with a text editor, such as Microsoft Notepad or Apple TextEdit. You can view the model's data and metadata, including its original file name, creation date, and the application that created the file.

When opened in a text editor or source code editor, you can modify the properties of the STEP file. However, if you incorrectly edit the file, you may inadvertently corrupt the file.

How to convert an STEP file

Various CAD applications, including Autodesk Fusion 360, Dassault Systemes SolidWorks, and IMSI TurboCAD, can convert STEP files to other formats.

For example, Autodesk Fusion 360 can convert STEP files to various file types, including the following formats:

  • .OBJ - Wavefront 3D Object
  • .3MF - 3D Manufacturing File
  • .ASM - Pro/ENGINEER Assembly File
  • .DWG - AutoCAD Drawing
  • .DXF - Drawing Exchange Format
  • .IGES - IGES Drawing File
  • .STL - Stereolithography File
  • .FBX - Autodesk FBX Interchange File
  • .F3D - Fusion 360 Archive
  • .USD - Universal Scene Description Format
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Programs that open STEP files

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The FileInfo.com team has independently researched the STEP 3D Model file format and Mac, Windows, Linux, Android, and iOS apps listed on this page. Our goal is 100% accuracy and we only publish information about file types that we have verified.

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