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For software developers · 3D InterOp SDK

Convert RFA to CATIA V4 in your application

3D InterOp is a CAD interoperability SDK that lets your software read RFA files and write CATIA V4, 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 CATIA V4
  • Mixed geometry → exact geometry
  • C++ / C# APIs
component.rfaRevit family · BIM component
Your application
3D InterOp SDK
Revit readerHealingCATIA V4 writer
part.modelCATIA V4 · exact B-Rep

RFA to CATIA V4 at a glance

Revit family can mix exact solids and facets; CATIA V4 stores exact geometry. Exact elements are written as exact geometry, and elements stored only as facets stay faceted.

Revit family (source)CATIA V4 (target)
Full nameRevit familyCATIA Version 4
Standard / ownerAutodeskDassault Systèmes
File extensions.rfa.model, .exp, .session
GeometryB-Rep and mesh (read); mesh (written by 3D InterOp)Exact B-Rep
Assemblies / structureNested families; assembly structure written by 3D InterOpYes (written as parts only)
3D InterOp supportRead and writeRead and write

What's preserved, what changes

Here is what your application can expect to carry across from Revit family to CATIA V4.

  • Preserved
    Exact geometry
    Exact B-Rep read from RFA is written to CATIA V4 as exact geometry.
  • Changes
    Assembly flattened
    The CATIA V4 writer exports parts only: flatten the RFA assembly into a single body before export, or the .model file is empty.
  • Changes
    Faceted parts
    Parts the RFA file stores only as facets are written as facets.

Why software vendors add RFA to CATIA V4 conversion

Deliver in your customer’s CAD format

Aerospace and automotive OEMs often require supplier data in CATIA V4. Writing it lets your users meet that requirement directly from your application.

Exact geometry, ready to edit

CATIA V4 keeps exact B-Rep geometry, so the receiving engineer can measure, modify or machine the model in CATIA.

No neutral-format round trip

Writing CATIA V4 directly avoids an extra STEP or IGES step, and the loss each extra translation can add.

Things to check before you ship

  • Written CATIA V4 versions: CATIA 4.1.9 to 4.2.4 (.model).
  • The CATIA V4 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 Study

About the formats

  • 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.

  • Target format

    What is a CATIA V4 (.model) file?

    CATIA V4 is the legacy generation of Dassault Systèmes’ CATIA, whose models are mostly stored in .model files. Many aerospace and automotive archives still hold CATIA V4 data.

Frequently asked questions

The exact B-Rep that 3D InterOp reads from RFA is written to CATIA V4; parts stored only as facets stay faceted.

No. The CATIA V4 writer exports parts only: flatten the assembly into a single body before export, or the .model file is empty.

No. The CATIA V4 writer isn’t available in 3D InterOp CGM.

3D InterOp reads Revit 2015 to 2026.

3D InterOp writes CATIA 4.1.9 to 4.2.4 (.model).

Yes. 3D InterOp reads and writes both formats, so CATIA V4 to RFA is supported too.

  • Building software that needs to convert RFA to CATIA V4?

    3D InterOp is an SDK that lets your application read Revit family and write CATIA V4 alongside 30+ CAD and BIM formats.