Convert PRT to STEP

A supplier, CAD system, CNC workflow, or viewer may require a STEP file when it cannot open the original PRT file. Conversion also provides a neutral copy for exchange, but the correct method depends on which CAD program created the .prt file.

What the PRT format is

.prt is not one standardized CAD format. PTC Creo Parametric and older Pro/ENGINEER use it for native parts; Siemens NX commonly uses it for parts and some assemblies; CADKEY also has its own PRT format. These files can contain feature history, sketches, constraints, equations, configurations, materials, and references that a neutral exchange file will not preserve.

Identify the source application and version before choosing a converter. A text editor cannot reliably identify the PRT variant. Ask the file provider, inspect its metadata in a compatible CAD system, or use a translator that explicitly lists support for the relevant Creo, NX, or CADKEY format.

What the STEP format is

STEP, normally saved as .step or .stp, is the neutral ISO 10303 format used to exchange CAD product data between systems such as Creo, NX, SOLIDWORKS, CATIA, Inventor, Fusion, FreeCAD, CAM, inspection, and viewing software.

STEP generally transfers solid and surface geometry, assemblies, colors, and selected product metadata without preserving the source system's editable feature tree. Use AP242 when both systems support it; AP214 remains common, and AP203 is an older profile with fewer data capabilities. The receiving application, not only the export setting, determines which PMI, tolerances, attributes, layers, materials, and assembly information survives import.

Convert with the native CAD application

The source application is usually the most reliable converter because it can resolve native references and regeneration problems before export.

• Creo Parametric: open the file in the creating release or a compatible newer release, regenerate the model, and resolve failed features. Use File → Save As → Save a Copy, select STEP (*.stp, *.step), choose the available AP242 or AP214 profile and required body or assembly options, then save.
• Siemens NX: open and update the PRT, load all required assembly components, then use the release-specific File → Export → STEP command. Select AP203, AP214, or AP242 if offered, set units and component options, and export as .stp or .step.
• SOLIDWORKS: if the installed version and licensed translators support the Creo or NX file, use File → Open, select the appropriate native file type, import the model, and use File → Save As with STEP AP214 or another required STEP option. Native translator support varies by release and file version.

After export, reopen the STEP in a separate CAD system or viewer. Check units, orientation, body and component counts, assembly placement, colors, and critical dimensions rather than relying on the export completing without an error.

Use a dedicated desktop converter

CAD Exchanger Desktop can convert supported Creo and NX PRT variants to STEP without the original CAD application. Open the file, use File → Export, select STEP, choose AP242 or AP214 when available, configure assembly and unit options, and export. Datakit CrossManager is another commercial option, particularly for batch conversion; verify its support matrix for the exact source application and version before processing files.

Generic conversion software is not interchangeable merely because it accepts the .prt extension. A converter that supports Creo PRT may not support NX or CADKEY PRT, and an unrecognized file can produce an empty, incomplete, or invalid STEP file.

Use an online converter carefully

CAD Exchanger Cloud is a reputable browser-based option for supported PRT variants. Upload the file, select STEP and the available protocol or export settings, download the result, and validate it in a CAD viewer. Confirm source-format and version support before uploading; browser services may not expose the same assembly, PMI, or AP242 controls as desktop software.

Do not upload proprietary, export-controlled, or customer-owned designs unless the service's encryption, retention, deletion, and data-use terms meet the project requirements. Use a desktop converter or the native CAD system for confidential files.

Quality and compatibility limits

• Feature history, sketches, constraints, equations, design intent, and parametric relationships are normally lost. The result is exchanged geometry, not an editable native Creo, NX, or CADKEY model.
• STEP records units, but import settings or a faulty translator can still scale the model incorrectly. Compare a known dimension after import.
• Suppressed, hidden, lightweight, unloaded, or failed components may be excluded. Resolve regeneration errors and load required assembly references before export.
• Threads, tiny fillets, sliver faces, gaps, and complex surfaces can translate imperfectly. Run the receiving system's geometry or healing check and inspect critical features.
• PMI, tolerances, materials, textures, colors, layers, and attributes depend on the exporter, STEP application protocol, and importer. Verify these separately from the solid geometry.
• For manufacturing or inspection, compare critical dimensions and datums with the original PRT and obtain approval of the imported model before using it for tooling, machining, or measurement.