Convert RFA to 3DXML in your application
3D InterOp is a CAD interoperability SDK that lets your software read RFA files and write 3DXML, generating the 3DXML 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 3D XML
- Mixed geometry → triangle mesh
- C++ / C# APIs
RFA to 3DXML at a glance
Revit family can mix exact solids and facets; 3D XML stores triangles only, so the whole model is tessellated when it is written.
| Revit family (source) | 3D XML (target) | |
|---|---|---|
| Full name | Revit family | 3D XML |
| Standard / owner | Autodesk | Dassault Systèmes |
| File extensions | .rfa | .3dxml |
| Geometry | B-Rep and mesh (read); mesh (written by 3D InterOp) | Tessellated geometry |
| Assemblies / structure | Nested families; assembly structure written by 3D InterOp | Yes |
| PMI | None | Graphical PMI |
| 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 3D XML.
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Preserved
Product structureThe RFA product structure is written to 3DXML.
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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 3DXML conversion
Lightweight review
3D XML 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 3D XML file gives them the shape in a format their tools can open.
Easier handling of large assemblies
Without exact surfaces and feature data, 3D XML files are easier to transfer and display, even for large assemblies.
Things to check before you ship
- Written 3DXML versions: 3D XML 4.3, as static tessellation.
- Only static tessellation is written, not XML tessellation.
- 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 a 3D XML (.3dxml) file?
3D XML is Dassault Systèmes’ lightweight XML-based format for sharing 3D product data. 3D InterOp reads and writes its tessellated representation, with product structure and graphical PMI.
Frequently asked questions
3D InterOp tessellates the geometry it reads from RFA when it writes 3DXML. Your application sets the tolerances, so it controls the trade-off between accuracy and file size.
Yes. 3D InterOp reads the RFA product structure and writes it to 3DXML.
3D InterOp writes 3D XML 4.3 with static tessellation. XML tessellation isn’t written.
3D InterOp reads Revit 2015 to 2026.
3D InterOp writes 3D XML 4.3, as static tessellation.
Yes. 3D InterOp reads and writes both formats, so 3DXML to RFA is supported too.
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Building software that needs to convert RFA to 3DXML?
3D InterOp is an SDK that lets your application read Revit family and write 3D XML alongside 30+ CAD and BIM formats.