Convert PRT to IGS

A supplier, CAM package, or inspection system may require an IGES file when it cannot open a native .prt part. Exporting from the CAD system that created the model is usually the most reliable way to provide the required geometry.

What the PRT format is

.prt is not a single universal file format. It is a native part-file extension used prominently by PTC Creo (formerly Pro/ENGINEER) and Siemens NX, as well as some other CAD and engineering applications.

Depending on its source, a PRT file may contain solid and surface geometry, parametric features, sketches, materials, layers, PMI, and links to assemblies or external references. These native data structures are version- and application-dependent, so identify the application that created the file before attempting conversion. Renaming a file from .prt to .igs does not convert it.

What the IGS format is

.igs and .iges are extensions for IGES (Initial Graphics Exchange Specification), a neutral CAD exchange format. IGES can carry wireframe entities, curves, surfaces, trimmed NURBS geometry, colors, layers, and some solid boundary-representation data.

IGES remains common in legacy CAM, mold-design, CMM inspection, and supplier workflows, particularly where surface geometry is required. It does not retain a CAD system's editable feature tree, sketch constraints, parametric dimensions, assembly constraints, or most proprietary attributes. An imported IGES model is normally treated as dumb geometry.

Convert a PRT file to IGS

Open the file in its originating CAD application, regenerate or update the model if required, and inspect it before export. Export the final model state rather than an incomplete or failed regeneration state.

• PTC Creo: Open the part, then use File → Save As → Save a Copy. Select IGES as the output type, specify a filename such as part.igs, review the export options, and save.
• Siemens NX: Open the part and use File → Export → IGES. Select the part or objects to export, set the output filename, units, and translator options, then run the export.
• Other CAD software: Use its IGES command under File → Export or File → Save As. If it cannot read the particular PRT variant, request a STEP or IGES export from the model author instead.

If the original CAD system is unavailable, use a translator that explicitly supports the source PRT family and file version. CAD Exchanger is a desktop option for supported Creo and NX formats; import the actual file, inspect the result, and export it as IGES. Native CAD support varies by product release and license, so confirm compatibility before buying software.

For non-confidential, small files, CAD Exchanger Cloud can be considered if its current supported-format list explicitly includes the originating PRT type and version. Do not upload controlled, confidential, or customer-owned CAD data to a third-party service without approval.

Check the exported geometry

Set export units deliberately and verify a known dimension after import. Although IGES can store unit information, older importers may ignore it or apply an incorrect default, causing inch-to-millimeter scale errors.

If the recipient needs a closed machinable solid, confirm which IGES entity types its CAD/CAM system supports. Some importers accept trimmed surfaces but produce separate faces rather than a valid solid. STEP is generally preferable for exchanging solid models when the receiving system accepts it, but IGES is appropriate when the recipient specifically requires it.

Open the resulting .igs file in the destination application and check for missing faces, open edges, gaps, failed trims, and reversed surface normals. Run geometry healing or validation before toolpath generation, meshing, inspection, or manufacturing. Export assembly components separately unless the recipient has confirmed support for the selected IGES assembly representation; native assembly constraints will not transfer reliably.