Convert RFA to FBX in your application
3D InterOp is a CAD interoperability SDK that lets your software read RFA 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 Revit family · Writes FBX
- Mixed geometry → triangle mesh
- C++ / C# APIs
RFA to FBX at a glance
Revit family can mix exact solids and facets; FBX stores triangles only, so the whole model is tessellated when it is written.
| Revit family (source) | FBX (target) | |
|---|---|---|
| Full name | Revit family | Filmbox |
| Standard / owner | Autodesk | Autodesk |
| File extensions | .rfa | .fbx |
| Geometry | B-Rep and mesh (read); mesh (written by 3D InterOp) | Triangle mesh |
| Assemblies / structure | Nested families; assembly structure written by 3D InterOp | Yes: scene hierarchy |
| 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 Revit family to FBX.
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Changes
Geometry is tessellatedThe exact Revit family 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 RFA 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 RFA input: Revit 2015 to 2026.
- 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 StudyAbout the formats
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Source format
What is an RFA (.rfa) file?
An RFA file is a Revit family: a reusable component such as a door, a window or a piece of equipment, with its geometry, types and parameters, loaded into Revit projects.
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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 RFA 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.
3D InterOp reads Revit 2015 to 2026.
3D InterOp writes FBX 7.7.0.
Yes. 3D InterOp reads and writes both formats, so FBX to RFA is supported too.
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Building software that needs to convert RFA to FBX?
3D InterOp is an SDK that lets your application read Revit family and write FBX alongside 30+ CAD and BIM formats.