Convert CATProduct to STP in your application
3D InterOp is a CAD interoperability SDK that lets your software read CATProduct files and write STP, 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 CATProduct · Writes STEP
- Exact geometry → exact geometry
- C++ / C# APIs
CATProduct to STP at a glance
Both formats store exact geometry, so the model stays exact. The differences are in the product data each one can carry.
| CATProduct (source) | STEP (target) | |
|---|---|---|
| Full name | CATIA V5 Product (assembly) | Standard for the Exchange of Product model data |
| Standard / owner | Dassault Systèmes | ISO 10303 — AP203, AP214, AP242 |
| File extensions | .CATProduct | .stp, .step |
| Geometry | Exact B-Rep (in the referenced parts) | Exact B-Rep |
| Assemblies / structure | Yes | Yes |
| PMI | Semantic and graphical | Graphical and semantic (AP242) |
| 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 CATProduct to STEP.
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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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Preserved
Product structureThe CATProduct product structure is written to STP.
Why software vendors add CATProduct to STP conversion
Supplier and OEM exchange
STEP is the ISO standard most supply chains specify for exchanging 3D models. Writing it lets your users send data to partners on any CAD system.
Model-based definition
STEP AP242 can carry semantic PMI next to exact geometry, so your users can share models together with their manufacturing data.
Long-term archiving
As an ISO standard independent of any CAD vendor, STEP is widely used to archive product data.
Things to check before you ship
- Written STP versions: AP203, AP214 or AP242 (.stp, .step or .stpx).
- Semantic PMI in STEP AP242 needs a license in addition to the STEP writer.
- Supported CATProduct input: CATIA V5 R8 to V5-6 R2026.
- Test PMI transfer end to end with real CATProduct files from your users.
- 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 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.
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Target format
What is a STEP (.stp) file?
STEP is the ISO 10303 standard for exchanging 3D product data between CAD systems. Its application protocols range from exact geometry (AP203, AP214) to full model-based definition with PMI (AP242).
Frequently asked questions
Yes. Both formats store exact B-Rep geometry, so the model is translated without being tessellated into triangles.
3D InterOp reads PMI from CATProduct, and semantic PMI can be written to STEP AP242 with the additional STEP AP242 license.
Yes. 3D InterOp reads the CATProduct product structure and writes it to STP.
The STEP writer supports AP203, AP214 and AP242, with AP214 as the default. Your application sets the version at export; semantic PMI is written to AP242 only.
No. 3D InterOp reads CATProduct files directly, without CATIA or a CATIA license on the machine.
3D InterOp reads CATIA V5 R8 to V5-6 R2026.
Yes. 3D InterOp reads and writes both formats, so STP to CATProduct is supported too.
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Building software that needs to convert CATProduct to STP?
3D InterOp is an SDK that lets your application read CATProduct and write STEP alongside 30+ CAD and BIM formats.