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For software developers · 3D InterOp SDK

Convert 3DXML to RFA in your application

3D InterOp is a CAD interoperability SDK that lets your software read 3DXML 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.

Explore 3D InterOp
  • Reads 3D XML · Writes Revit family
  • Triangle mesh → triangle mesh
  • C++ / C# APIs
assembly.3dxml3D XML · tessellated · product structure
Your application
3D InterOp SDK
3D XML readerHealingRevit writer
component.rfaRevit family · BIM component

3DXML to RFA at a glance

Both formats store triangles, so the facets carry over without re-tessellation. The differences are in structure, appearance and metadata.

3D XML (source)Revit family (target)
Full name3D XMLRevit family
Standard / ownerDassault SystèmesAutodesk
File extensions.3dxml.rfa
GeometryTessellated geometryB-Rep and mesh (read); mesh (written by 3D InterOp)
Assemblies / structureYesNested families; assembly structure written by 3D InterOp
PMIGraphical PMINone
3D InterOp supportRead and writeRead and write

What's preserved, what changes

Here is what your application can expect to carry across from 3D XML to Revit family.

  • Preserved
    Mesh data
    The 3DXML facets are read and written to RFA without being re-tessellated.
  • Preserved
    Product structure
    The 3DXML product structure is written to RFA.
  • Changes
    Geometry written as mesh
    The Revit writer writes mesh only: exact B-Rep from 3DXML isn’t exported to the family.
  • Not carried
    PMI
    The Revit writer writes no PMI, so the PMI read from 3DXML isn’t written. Keep STEP AP242 as an output when PMI matters.

Why software vendors add 3DXML 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 3DXML input: 3D XML 4.0 to 4.3 (tessellated data only).
  • B-Rep stored in authoring-mode 3D XML files isn’t imported: only the tessellation is read.
  • 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 Study

About the formats

  • Source 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.

    Learn more about 3DXML files

  • 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.

    Learn more about RFA files

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).

The Revit writer writes no PMI, so the PMI read from 3DXML isn’t written. When PMI matters, offer STEP AP242 as an output.

Yes. 3D InterOp reads the 3DXML product structure and writes it to RFA.

No. The Revit writer writes the geometry as mesh, in millimeters, without Revit parameters.

No. B-Rep stored in authoring-mode 3D XML files isn’t imported: 3D InterOp reads the tessellation only.

3D InterOp reads 3D XML 4.0 to 4.3 (tessellated data only), as visualization data.

3D InterOp writes Revit 2026 families (.rfa).

  • Building software that needs to convert 3DXML to RFA?

    3D InterOp is an SDK that lets your application read 3D XML and write Revit family alongside 30+ CAD and BIM formats.
    Explore 3D InterOp Request an evaluation