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For software developers · 3D InterOp SDK

Convert 3DM to FBX in your application

3D InterOp is a CAD interoperability SDK that lets your software read 3DM files and write FBX, generating the FBX mesh from the geometry it reads, with tessellation settings your application controls.

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 FBX
  • Exact geometry → triangle mesh
  • C++ / C# APIs
shape.3dmRhino · NURBS surfaces
Your application
3D InterOp SDK
Rhino readerTessellationFBX writer
scene.fbxFBX · mesh scene

3DM to FBX at a glance

Rhino stores exact geometry; FBX stores triangles. The translation is a tessellation, and the settings you choose decide how close the mesh stays to the original.

Rhino (source)FBX (target)
Full nameRhinoceros 3D modelFilmbox
Standard / ownerRobert McNeel & AssociatesAutodesk
File extensions.3dm.fbx
GeometryExact NURBS geometry and meshesTriangle mesh
Assemblies / structureNo assembly hierarchyYes: scene hierarchy
3D InterOp supportRead onlyRead and write

What's preserved, what changes

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

  • Changes
    Geometry is tessellated
    The exact Rhino B-Rep is replaced by a triangle mesh, generated by 3D InterOp from the exact geometry it reads. Accuracy depends on the tessellation settings your application uses.

Why software vendors add 3DM to FBX conversion

Lightweight review

FBX carries tessellated geometry that opens much faster than the full CAD model, so design reviews and digital mockups stay responsive.

Sharing outside engineering

Marketing, training and sales teams rarely have CAD software. A FBX file gives them the shape in a format their tools can open.

Easier handling of large assemblies

Without exact surfaces and feature data, FBX files are easier to transfer and display, even for large assemblies.

Things to check before you ship

  • Written FBX versions: FBX 7.7.0.
  • Points and wires aren’t written to FBX.
  • The FBX writer is available through the UConnect interface only.
  • Supported 3DM input: Rhino 2 to 8.
  • Test tessellation settings on your heaviest parts: finer meshes mean larger files.
  • 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 an FBX (.fbx) file?

    FBX is Autodesk’s format for exchanging 3D scenes between content-creation, game and real-time tools. It stores meshes, materials and the scene hierarchy.

Frequently asked questions

3D InterOp tessellates the geometry it reads from 3DM when it writes FBX. Your application sets the tolerances, so it controls the trade-off between accuracy and file size.

No. The FBX writer writes meshes; points and wires from the source aren’t written.

The FBX writer is available through the 3D InterOp UConnect interface.

No. 3D InterOp reads Rhino geometry, but importing mapping data isn’t supported.

3D InterOp reads Rhino 2 to 8.

3D InterOp writes FBX 7.7.0.

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 FBX?

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