Convert CATPart to CATProduct in your application
3D InterOp is a CAD interoperability SDK that lets your software read CATPart files and write CATProduct, with exact B-Rep geometry carried across and nothing tessellated, without a CATIA license.
Spatial does not offer an online converter or a desktop conversion app. 3D InterOp is a component that software vendors embed in their own products.
- Reads CATPart · Writes CATProduct
- Exact geometry → exact geometry
- C++ / C# APIs
CATPart to CATProduct at a glance
Both formats store exact geometry, so the model stays exact. The differences are in the product data each one can carry.
| CATPart (source) | CATProduct (target) | |
|---|---|---|
| Full name | CATIA V5 Part | CATIA V5 Product (assembly) |
| Standard / owner | Dassault Systèmes | Dassault Systèmes |
| File extensions | .CATPart | .CATProduct |
| Geometry | Exact B-Rep | Exact B-Rep (in the referenced parts) |
| Assemblies / structure | Part file (assemblies are CATProduct files) | Yes |
| PMI | Semantic and graphical | Semantic and graphical |
| 3D InterOp support | Read and write | Read and write |
What's preserved, what changes
Here is what your application can expect to carry across from CATPart to CATProduct.
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Preserved
Exact geometrySolids and surfaces stay exact B-Rep. The model is never reduced to a triangle mesh.
Why software vendors add CATPart to CATProduct conversion
Deliver in your customer’s CAD format
Aerospace and automotive OEMs often require supplier data in CATProduct. Writing it lets your users meet that requirement directly from your application.
Exact geometry, ready to edit
CATProduct keeps exact B-Rep geometry, so the receiving engineer can measure, modify or machine the model in CATIA.
No neutral-format round trip
Writing CATProduct directly avoids an extra STEP or IGES step, and the loss each extra translation can add.
Things to check before you ship
- Written CATProduct versions: CATIA V5 R15 to V5-6 R2026.
- A CATProduct written by 3D InterOp can’t reference files in other formats.
- Supported CATPart input: CATIA V5 R8 to V5-6 R2026.
- Validate a sample of translated files in the target system your users actually work with.
Working with Spatial was a real milestone for us: Thanks to the powerful 3DInterOp library, we were able to successfully bring our complex CAD-based solutions to the cloud while remaining flexible to meet individual customer requirements. For us, Spatial is not just a technology partner, but a true enabler of our product strategy.
Dr. Arno Michelis, Founder, Simus Systems
Read the Case StudyAbout the formats
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Source format
What is a CATPart (.CATPart) file?
A CATPart file is a CATIA V5 part: one component with its exact 3D geometry, features and, often, PMI. Assemblies of parts are stored in CATProduct files.
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Target format
What is a CATProduct (.CATProduct) file?
A CATProduct file is a CATIA V5 assembly. It defines the product structure and positions, and references the CATPart files that hold the geometry.
Frequently asked questions
Yes. Both formats store exact B-Rep geometry, so the model is translated without being tessellated into triangles.
No. A CATProduct written by 3D InterOp can’t reference files in other formats.
No. 3D InterOp reads CATPart files directly, without CATIA or a CATIA license on the machine.
3D InterOp reads CATIA V5 R8 to V5-6 R2026.
3D InterOp writes CATIA V5 R15 to V5-6 R2026.
Yes. 3D InterOp reads and writes both formats, so CATProduct to CATPart is supported too.
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Building software that needs to convert CATPart to CATProduct?
3D InterOp is an SDK that lets your application read CATPart and write CATProduct alongside 30+ CAD and BIM formats.