Convert DGN to RFA in your application
3D InterOp is a CAD interoperability SDK that lets your software read DGN files and write RFA, writing a Revit family (.rfa) as mesh geometry.
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 MicroStation DGN · Writes Revit family
- Exact geometry → triangle mesh
- C++ / C# APIs
DGN to RFA at a glance
MicroStation DGN stores exact geometry; Revit family stores triangles. The translation is a tessellation, and the settings you choose decide how close the mesh stays to the original.
| MicroStation DGN (source) | Revit family (target) | |
|---|---|---|
| Full name | MicroStation Design file | Revit family |
| Standard / owner | Bentley Systems | Autodesk |
| File extensions | .dgn | .rfa |
| Geometry | Exact B-Rep | B-Rep and mesh (read); mesh (written by 3D InterOp) |
| Assemblies / structure | Yes: models and references | Nested families; assembly structure written by 3D InterOp |
| 3D InterOp support | Read only | Read and write |
What's preserved, what changes
Here is what your application can expect to carry across from MicroStation DGN to Revit family.
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Preserved
Product structureThe DGN product structure is written to RFA.
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Changes
Geometry written as meshThe Revit writer writes mesh only: exact B-Rep from DGN isn’t exported to the family.
Why software vendors add DGN to RFA conversion
Bring product content into Revit
Manufacturers publish their products as Revit families so architects can place them in building models. Writing RFA files lets your users produce that content from CAD data.
Coordinate with Revit-based teams
Many building projects are modeled in Revit. A Revit family gives those teams the geometry in a form they can load into their project.
Fewer manual remodeling steps
Without a direct export, CAD parts are often remodeled by hand in Revit. Writing the family directly saves your users that step.
Things to check before you ship
- Written RFA versions: Revit 2026 families (.rfa).
- Revit families are written in millimeters, without Revit parameters.
- Supported DGN input: DGN V7 to V8.
- 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 a DGN (.dgn) file?
DGN is the native design file format of Bentley MicroStation, widely used for infrastructure, plant and civil engineering projects. It exists in two generations, V7 and V8.
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Target 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.
Frequently asked questions
No. The Revit writer writes mesh geometry only, without B-Rep or Revit parameters, for the latest Revit version (Revit 2026 in 3D InterOp 2026 1.0.1).
Yes. 3D InterOp reads the DGN product structure and writes it to RFA.
No. The Revit writer writes the geometry as mesh, in millimeters, without Revit parameters.
3D InterOp reads DGN V7 to V8.
3D InterOp writes Revit 2026 families (.rfa).
No. 3D InterOp reads DGN but doesn’t write it. To send data back to MicroStation users, write a neutral format they can import, such as IFC or STEP.
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Building software that needs to convert DGN to RFA?
3D InterOp is an SDK that lets your application read MicroStation DGN and write Revit family alongside 30+ CAD and BIM formats.