Convert RFA to VDA-FS in your application
3D InterOp is a CAD interoperability SDK that lets your software read RFA files and write VDA-FS, carrying across the exact geometry the RFA file contains.
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 VDA-FS
- Mixed geometry → exact geometry
- C++ / C# APIs
RFA to VDA-FS at a glance
Revit family can mix exact solids and facets; VDA-FS stores exact geometry. Exact elements are written as exact geometry, and elements stored only as facets stay faceted.
| Revit family (source) | VDA-FS (target) | |
|---|---|---|
| Full name | Revit family | VDA surface interface |
| Standard / owner | Autodesk | VDA (German automotive industry) |
| File extensions | .rfa | .vda |
| Geometry | B-Rep and mesh (read); mesh (written by 3D InterOp) | Exact curves and surfaces |
| Assemblies / structure | Nested families; assembly structure written by 3D InterOp | No assembly 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 VDA-FS.
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Preserved
Exact geometryExact B-Rep read from RFA is written to VDA-FS as exact geometry.
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Changes
Assembly structureVDA-FS has no native assembly hierarchy. Decide in your application how Revit family product structure is grouped or flattened before writing.
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Changes
Faceted partsParts the RFA file stores only as facets are written as facets.
Why software vendors add RFA to VDA-FS conversion
Legacy CAD and CAM systems
Many established engineering tools still consume VDA-FS first. Writing it lets your users hand data to them without leaving your application.
Supplier and partner exchange
Some suppliers and manufacturing partners still specify VDA-FS in their exchange requirements. Your software can meet them directly.
Geometry-only workflows
When a downstream process needs exact part geometry and nothing more, VDA-FS is a simple, widely readable target.
Things to check before you ship
- Written VDA-FS versions: VDA-FS 2.0.
- The VDA-FS writer isn’t available in 3D InterOp CGM.
- Supported RFA input: Revit 2015 to 2026.
- 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 VDA-FS (.vda) file?
VDA-FS is a neutral surface-exchange format defined by the German automotive association VDA. It stores exact curves and free-form surfaces, and is still found in automotive supply chains.
Frequently asked questions
The exact B-Rep that 3D InterOp reads from RFA is written to VDA-FS; parts stored only as facets stay faceted.
VDA-FS has no assembly hierarchy, so your application decides how the RFA structure is grouped or flattened before writing.
No. The VDA-FS writer isn’t available in 3D InterOp CGM.
3D InterOp reads Revit 2015 to 2026.
3D InterOp writes VDA-FS 2.0.
Yes. 3D InterOp reads and writes both formats, so VDA-FS to RFA is supported too.
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Building software that needs to convert RFA to VDA-FS?
3D InterOp is an SDK that lets your application read Revit family and write VDA-FS alongside 30+ CAD and BIM formats.