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For software developers · 3D InterOp SDK

Convert OBJ to FBX in your application

3D InterOp is a CAD interoperability SDK that lets your software read OBJ files and write FBX, carrying the mesh data across without re-tessellating it.

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 OBJ · Writes FBX
  • Triangle mesh → triangle mesh
  • C++ / C# APIs
part.objOBJ · polygon mesh
Your application
3D InterOp SDK
OBJ readerTessellationFBX writer
scene.fbxFBX · mesh scene

OBJ to FBX at a glance

Both formats store triangles, so the facets carry over without re-tessellation. The differences are in structure, appearance and metadata.

OBJ (source)FBX (target)
Full nameWavefront OBJFilmbox
Standard / ownerOpen formatAutodesk
File extensions.obj.fbx
GeometryPolygon meshTriangle mesh
Assemblies / structureNo assembly hierarchyYes: scene hierarchy
3D InterOp supportRead and writeRead and write

What's preserved, what changes

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

  • Preserved
    Mesh data
    The OBJ facets are read and written to FBX without being re-tessellated.

Why software vendors add OBJ 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 OBJ input: any OBJ version.
  • 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 an OBJ (.obj) file?

    OBJ is a simple, widely supported text format for polygon meshes, created by Wavefront. It describes vertices, faces and texture coordinates, with materials in a separate .mtl file.

  • 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

No re-tessellation is needed. 3D InterOp reads the OBJ facets as visualization data and writes them to FBX.

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.

Yes. 3D InterOp reads the visual material properties of OBJ files on import.

3D InterOp reads any OBJ version, as visualization data.

3D InterOp writes FBX 7.7.0.

Yes. 3D InterOp reads and writes both formats, so FBX to OBJ is supported too.

  • Building software that needs to convert OBJ to FBX?

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