Convert RFA to IGES in your application
3D InterOp is a CAD interoperability SDK that lets your software read RFA files and write IGES, 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 IGES
- Mixed geometry → exact geometry
- C++ / C# APIs
RFA to IGES at a glance
Revit family can mix exact solids and facets; IGES stores exact geometry. Exact elements are written as exact geometry, and elements stored only as facets stay faceted.
| Revit family (source) | IGES (target) | |
|---|---|---|
| Full name | Revit family | Initial Graphics Exchange Specification |
| Standard / owner | Autodesk | ANSI |
| File extensions | .rfa | .igs, .iges |
| Geometry | B-Rep and mesh (read); mesh (written by 3D InterOp) | Exact B-Rep and surfaces |
| Assemblies / structure | Nested families; assembly structure written by 3D InterOp | No native 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 IGES.
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Preserved
Exact geometryExact B-Rep read from RFA is written to IGES as exact geometry.
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Changes
Assembly structureIGES 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 IGES conversion
Legacy CAD and CAM systems
Many established engineering tools still consume IGES 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 IGES in their exchange requirements. Your software can meet them directly.
Geometry-only workflows
When a downstream process needs exact part geometry and nothing more, IGES is a simple, widely readable target.
Things to check before you ship
- Written IGES versions: IGES 5.3.
- 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 an IGES (.igs) file?
IGES is one of the earliest neutral CAD formats, an ANSI standard for exchanging 2D and 3D geometry. It stores exact curves, surfaces and solids, but not the product structure and manufacturing data STEP can carry.
Frequently asked questions
The exact B-Rep that 3D InterOp reads from RFA is written to IGES; parts stored only as facets stay faceted.
IGES has no assembly hierarchy, so your application decides how the RFA structure is grouped or flattened before writing.
3D InterOp reads Revit 2015 to 2026.
3D InterOp writes IGES 5.3.
Yes. 3D InterOp reads and writes both formats, so IGES to RFA is supported too.
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Building software that needs to convert RFA to IGES?
3D InterOp is an SDK that lets your application read Revit family and write IGES alongside 30+ CAD and BIM formats.