Convert CATPart to XCGM in your application
3D InterOp is a CAD interoperability SDK that lets your software read CATPart files and write XCGM, 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 XCGM
- Exact geometry → exact geometry
- C++ / C# APIs
CATPart to XCGM 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) | XCGM (target) | |
|---|---|---|
| Full name | CATIA V5 Part | CGM native file |
| Standard / owner | Dassault Systèmes | Dassault Systèmes / Spatial (CGM Modeler) |
| File extensions | .CATPart | .xcgm |
| Geometry | Exact B-Rep | Exact B-Rep |
| Assemblies / structure | Part file (assemblies are CATProduct files) | Yes |
| PMI | Semantic and graphical | Semantic (read) |
| 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 XCGM.
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Preserved
Exact geometrySolids and surfaces stay exact B-Rep. The model is never reduced to a triangle mesh.
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Not carried
PMI3D InterOp doesn’t write PMI to XCGM, so the PMI read from CATPart isn’t written. Keep STEP AP242 as an output when PMI matters.
Why software vendors add CATPart to XCGM conversion
Hand models to kernel-based applications
Many CAD, CAM and CAE applications are built on the XCGM kernel. Writing XCGM gives them exact geometry they can load without another translation step.
Downstream modeling and analysis
An exact XCGM B-Rep can still be edited, meshed or machined by downstream tools, which a tessellated export would not allow.
Exchange within one ecosystem
Partners whose tools share the XCGM kernel often prefer to exchange XCGM files directly.
Things to check before you ship
- Written XCGM versions: R2012 to 2025 1.0.
- PMI and miscellaneous data aren’t written to XCGM.
- 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 an XCGM (.xcgm) file?
XCGM is the native file format of the CGM geometric kernel, used by CGM Modeler and Dassault Systèmes applications. It stores exact B-Rep geometry.
Frequently asked questions
Yes. Both formats store exact B-Rep geometry, so the model is translated without being tessellated into triangles.
3D InterOp doesn’t write PMI to XCGM, so the PMI read from CATPart isn’t written. When PMI matters, offer STEP AP242 as an output.
No. PMI and miscellaneous data aren’t written to XCGM.
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 R2012 to 2025 1.0.
Yes. 3D InterOp reads and writes both formats, so XCGM to CATPart is supported too.
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Building software that needs to convert CATPart to XCGM?
3D InterOp is an SDK that lets your application read CATPart and write XCGM alongside 30+ CAD and BIM formats.