.STP File Extension


Developer International Organization for Standardization
3.6  |  183 Votes

What is an STP file?

An STP file is a 3D assembly file supported by various mechanical design programs, such as IMSI TurboCAD and Autodesk Fusion 360. It contains three-dimensional object data saved in the Standard for the Exchange of Product Data (STEP) format. STP files are saved in a text-based ASCII format that conforms to the STEP Application Protocols ISO 10303-2xx.

More Information

Screenshot of a .stp file in Autodesk Fusion 360 2.0
STP file open in Autodesk Fusion 360 2.0

The STEP file format is a standardized 3D model format that engineers can use to save and transfer 3D models between different computer-aided design (CAD) and computer-aided manufacturing (CAM) programs. Before the STEP format's existence, users of one program often could not open models created in another program, making it difficult to share 3D models among users.

Most STEP files are saved with the .stp file extension. However, you may also encounter STEP models saved with the .step extension (.STEP files). The files contain plain text data that a CAD or CAM program references to load a 3D model. For example, many STP files contain data used to show a model of a manufactured mold or part.

How to open an STP file

You can open an STP file with various CAD applications, including Autodesk Fusion 360 (cross-platform, FreeCAD (cross-platform), IMSI TurboCAD (Windows, Mac), and Dassault Systemes CATIA (Windows, Linux).

For example, to open an STP 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 STP file

Opening a STP file with a text editor

STP file open in Microsoft Notepad
STP file open in Microsoft Notepad

Since STP files are saved in plain text, you can open an STP file with a text editor, such as Microsoft Notepad or Apple TextEdit, or a source code editor. When opened in a text or source code editor, you can view the STEP model data and metadata.

You can also modify the properties of an STP file with a text or source code editor. However, if you incorrectly change the file properties, you may inadvertently corrupt the file.

How to convert an STP file

Several CAD applications, including Autodesk Fusion 360, IMSI TurboCAD, and Siemens Solid Edge, can convert STP files to other formats.

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

  • .OBJ - Wavefront 3D Object
  • .3MF - 3D Manufacturing File
  • .DWG - AutoCAD Drawing
  • .DXF - Drawing Exchange Format
  • .ASM - Pro/ENGINEER Assembly File
  • .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 STP files

RoboHelp Stop List File

Developer Adobe Systems
2.8  |  17 Votes

Plain text file created by RoboHelp, a Windows help authoring program; saves a stop list which contains keywords that the Smart Index wizard ignores when creating the help documentation search index; can only be 512 characters long; created as part of a RoboHelp project (.XPJ).

More Information

Stop lists usually contain words such as "the," "or," and "a." These are words that typically aren't useful to index as keywords for help documentation searches.

Programs that open or reference STP files

Free Trial

SharePoint Template

Developer Microsoft
2.4  |  11 Votes

Website template created for Microsoft SharePoint, a Web-based collaboration program; contains a predesigned website that can be loaded from the SharePoint template gallery; used as a starting point for creating new websites.

More Information

To create an STP file, click "Site Settings." Then, under "Administration," choose "Go to Site Administration." Under Management and Statistics, select "Save site as template."

NOTE: SharePoint STP files only contain information about what is customized in the site. They do not include the complete definition of the website.

Programs that open STP files

Microsoft Office SharePoint Server

Analysis Studio Project Information File

Developer Appricon
1.9  |  8 Votes

An STP file contains project information created by Analysis Studio, a program used for data mining and statistical analysis. It stores the actions, data transformations, and variables that allow a data set to be reconstructed from an original data set. STP files are saved in an XML format.

More Information

When Analysis Studio is in online mode, data may be downloaded and reconstructed from a remote Analysis Server. When in offline mode, .DATA files stored on the local machine are used.

NOTE: Appricon no longer develops Analysis Studio.

Programs that open STP files

Appricon Analysis Studio

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