Convert PRT to CATPART

CATIA V5 requires a .CATPart document when a part delivered from Creo or Siemens NX must be edited, checked, assembled, or archived in CATIA. The conversion is normally a geometry transfer through STEP because the source and target systems use different native feature models.

What the PRT format is

.prt is an ambiguous CAD extension. In mechanical design it commonly identifies a Creo Parametric or Pro/ENGINEER part, or a Siemens NX part; these are different proprietary formats despite sharing the extension. Identify the creating application and its version before selecting a converter.

A native PRT can contain solid and surface geometry, sketches, constraints, parameters, construction geometry, materials, and a history-based feature tree. These items are generally specific to the source system and are not fully preserved by STEP or other neutral-format transfers.

What the CATPART format is

.CATPart is the native part-document format of Dassault Systèmes CATIA V5. A native CATPart can store bodies, features, sketches, parameters, geometric relationships, and other CATIA design data for editing, assembly integration, drafting, tooling, and product-data management.

A translated CATPart normally contains imported solid or surface geometry rather than a recreated Creo or NX feature history. It can be measured and used in assemblies, but changing the original design intent may require remodeling features in CATIA.

Convert a Creo or Pro/ENGINEER PRT

1. Open the PRT in the Creo or Pro/ENGINEER release that created it, or in a compatible newer release. Resolve regeneration failures before export.
2. Choose File → Save As → Save a Copy and select STEP (*.stp, *.step). Use AP242 or AP214 when supported by both the Creo exporter and the CATIA STEP interface; AP203 is a fallback for older installations.
3. Export the required bodies, retain the source units, and enable geometry healing or validation options provided by the exporter.
4. In CATIA V5, choose File → Open and open the STEP file through the installed STEP interface. The exact menu behavior depends on the CATIA V5 release and licensed interfaces.
5. Check the imported body for gaps, missing faces, extra bodies, incorrect scale, and solid status. Save the result with File → Save As as part.CATPart.

Convert a Siemens NX PRT

1. Open the part in Siemens NX and choose File → Export → STEP.
2. Select AP242 or AP214 if available, export the required bodies, confirm the unit setting, and enable sewing or healing where appropriate.
3. Open the resulting .stp file in CATIA V5, validate the geometry, and save it as .CATPart.

Use a translator when the source CAD system is unavailable

A licensed desktop translator such as Datakit CrossManager or CAD Exchanger Desktop can be suitable when its current format matrix explicitly lists the exact Creo or NX PRT variant as input and CATIA V5 .CATPart as output. Do not assume that support for Creo PRT includes NX PRT.

A browser-based service such as CAD Exchanger Cloud may provide the same route without installing CAD software, but confirm native .CATPart output, file-size limits, supported PRT variant, and CATIA version before uploading. Avoid online conversion for export-controlled, confidential, or supplier-restricted designs unless the service’s data-handling terms permit it. If the service outputs only STEP, import that STEP in CATIA and save a CATPart locally.

Quality and compatibility limits

STEP usually transfers boundary-representation solids and surfaces, but not the source feature tree, design history, sketches, constraints, feature names, parameters, system-specific references, or all material and metadata. The CATIA result may therefore be an imported or “dumb” solid.

After import, use CATIA’s geometry-checking and healing functions to inspect open surfaces, disconnected bodies, sliver faces, invalid topology, and tolerance problems. Compare critical dimensions and mass properties with the source model before manufacturing, tooling, or simulation. Unit mismatches can create apparently valid geometry at the wrong scale.

An assembly is not transferred by converting one PRT. Export each required component and separately rebuild the assembly structure, positioning constraints, links, and product document in CATIA unless the selected translator explicitly supports assembly conversion.