Convert CATPRODUCT to STP

A supplier or downstream CAD system may require ISO STEP instead of a native CATIA assembly, and many inspection, CAM, and viewing tools cannot open .CATProduct directly. Exporting to .stp or .step provides a neutral file for exchange without requiring CATIA.

What the CATPRODUCT format is

.CATProduct is CATIA V5's native assembly-document format. It stores the product structure, component instances, placements, constraints, links, and references to external .CATPart and nested .CATProduct files; the top-level file commonly does not contain all component geometry.

Dassault Systèmes CATIA creates CATPRODUCT files for mechanical, aerospace, automotive, and equipment design. A complete conversion therefore requires the referenced parts and subassemblies, not just the top-level product file.

What the STP format is

.stp and .step are filename extensions for ISO 10303 STEP, a neutral CAD exchange format. STEP normally carries exact boundary-representation solid and surface geometry rather than a mesh, and may preserve assembly hierarchy, names, colors, layers, and units depending on the exporter, application protocol, and importer.

STEP is accepted by many independent CAD, CAM, inspection, PLM, and visualization applications. It transfers the model without CATIA's parametric feature history, sketches, formulas, constraints, knowledge rules, or design tables, so the result is not a native CATIA feature tree.

How to convert the assembly in CATIA V5

1. Collect the top-level .CATProduct, every referenced .CATPart, nested product, and any linked file. Open the product in CATIA and resolve missing links before exporting. A CATPRODUCT supplied without its referenced components cannot generally produce complete geometry.
2. Open the STEP translator settings through Tools → Options → General → Compatibility → STEP. Menu names and available settings vary by CATIA V5 release, configuration, and licensed interfaces.
3. Use File → Save As and select a STEP type, or use the separate STEP export command when that command is provided by the installation. Choose an .stp or .step destination.
4. Select the application protocol required by the recipient. Use AP242 when both systems support it; AP214 remains common for automotive and general product exchange, while AP203 is an older option. Protocol availability depends on the CATIA release and license.
5. Export the top-level product, not only the active part. Enable assembly structure, names, colors, layers, and other metadata only when the receiving system supports them. Exclude construction or reference geometry only if it is not needed downstream.
6. Open the exported file in the recipient's CAD system or an independent STEP viewer. Compare component count, placements, orientations, units, visible solids, and critical dimensions with the CATIA assembly.

CATIA V5 is usually the safest option because it resolves native CATIA links and preserves the original assembly placements during export. Commercial translators such as Datakit CrossManager and CAD Exchanger can be alternatives when the current version explicitly supports the supplied CATIA V5 product and part revisions.

Online conversion options

Browser-based services such as CAD Exchanger Cloud may accept CATIA V5 assemblies and export STEP, but support depends on the service's current format list and on whether it accepts packaged assemblies rather than one isolated .CATProduct. Upload the complete referenced file set in the service's required archive or project format, then download and inspect the result.

Do not upload proprietary aerospace, automotive, or customer data unless the organization's security policy permits cloud processing. An online converter that accepts only the top-level CATPRODUCT can return an empty, partial, or link-broken STEP file.

Quality and compatibility limits

• STEP transfers geometry, not CATIA's editable design history. Plan for imported solids, surface bodies, or assembly components that can be measured and sometimes direct-edited in the destination CAD system.
• AP242 and AP214 can carry assembly organization, colors, and names, but importer support is inconsistent. Some applications flatten the assembly, discard metadata, or merge components.
• Export tolerance affects face sewing and solid healing. Start with the translator default; change it only when the destination reports gaps, open shells, or invalid solids.
• Check units in both applications. STEP includes unit information, but an importer configured incorrectly can display a model at the wrong scale.
• Large assemblies can take considerable time to translate and can create very large STEP files. Simplify or suppress unneeded components only when the recipient does not require them.
• Do not use a visualization-only or faceted export when the recipient needs precise CAD geometry. A mesh-based result is not equivalent to a solid STEP export.