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For software developers · 3D InterOp SDK

Convert 3DM to CATProduct in your application

3D InterOp is a CAD interoperability SDK that lets your software read 3DM files and write CATProduct, with exact B-Rep geometry carried across and nothing tessellated.

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 Rhino · Writes CATProduct
  • Exact geometry → exact geometry
  • C++ / C# APIs
shape.3dmRhino · NURBS surfaces
Your application
3D InterOp SDK
Rhino readerHealingCATIA V5 writer
assembly.CATProductCATIA V5 assembly · product structure

3DM 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.

Rhino (source)CATProduct (target)
Full nameRhinoceros 3D modelCATIA V5 Product (assembly)
Standard / ownerRobert McNeel & AssociatesDassault Systèmes
File extensions.3dm.CATProduct
GeometryExact NURBS geometry and meshesExact B-Rep (in the referenced parts)
Assemblies / structureNo assembly hierarchyYes
PMINot imported by 3D InterOpSemantic and graphical
3D InterOp supportRead onlyRead and write

What's preserved, what changes

Here is what your application can expect to carry across from Rhino to CATProduct.

  • Preserved
    Exact geometry
    Solids and surfaces stay exact B-Rep. The model is never reduced to a triangle mesh.

Why software vendors add 3DM 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 3DM input: Rhino 2 to 8.
  • 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 Study

About the formats

  • Source format

    What is a 3DM (.3dm) file?

    3DM is the native file format of Rhinoceros (Rhino), the NURBS modeler from Robert McNeel & Associates. It stores exact curves, surfaces and solids, as well as meshes.

  • 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 Rhino geometry, but importing mapping data isn’t supported.

3D InterOp reads Rhino 2 to 8.

3D InterOp writes CATIA V5 R15 to V5-6 R2026.

No. 3D InterOp reads 3DM but doesn’t write it. To send data back to Rhino users, write a neutral format they can import, such as STEP.

  • Building software that needs to convert 3DM to CATProduct?

    3D InterOp is an SDK that lets your application read Rhino and write CATProduct alongside 30+ CAD and BIM formats.