Convert RFA to STEP

A Revit family often must be supplied to a mechanical CAD, CAD/CAM, or product-development workflow that cannot open Autodesk’s RFA format. Converting it to STEP provides portable 3D geometry for inspection, assembly coordination, measurement, or further CAD work.

What the RFA format is

.rfa is Autodesk Revit’s family format, used by architects, engineers, BIM coordinators, manufacturers, and content authors for components such as doors, windows, furniture, fixtures, equipment, profiles, and annotation families.

An RFA can contain parameters, formulas, constraints, nested families, connectors, reference planes, materials, symbolic lines, and several detail or visibility representations. Revit project files use .rvt and can load RFA families. An RFA is not a single conventional CAD solid, so a conversion exports a selected geometric result rather than the family’s full parametric definition.

What the STEP format is

STEP is the ISO 10303 CAD exchange format, usually saved as .step or .stp. It is supported by applications including Autodesk Fusion, Inventor, SolidWorks, CATIA, Siemens NX, and FreeCAD.

A STEP file commonly contains precise boundary-representation surfaces and solids that other CAD and CAM systems can inspect, measure, assemble, or edit as imported geometry. It does not preserve Revit family types, formulas, constraints, views, schedules, BIM classification, or feature history.

Recommended conversion workflow

1. Open the RFA in Autodesk Revit. Use File → Open → Family if it is not already open in the Family Editor.
2. Set the required family type and parameter values. Revit exports the geometry generated by the active configuration, not every possible type or parameter state.
3. Open a 3D view and hide reference geometry, symbolic lines, unwanted nested components, and excessive detail. Confirm that the required solids are visible.
4. Export the view through File → Export → CAD Formats → ACIS (SAT). Select the 3D view and configure the export units before saving a file such as family.sat. The exact dialog names vary by Revit release; SAT export is available from Revit and, where supported, the Family Editor.
5. Open the SAT file in a mechanical CAD application that supports ACIS import. Autodesk Fusion can upload or open SAT files; Autodesk Inventor and some other CAD systems can also perform the intermediate conversion.
6. Inspect the imported model. Repair or stitch open surfaces, remove unwanted bodies, and check for failed blends or missing faces. A STEP export should contain valid solids when the recipient requires solid geometry.
7. Export through File → Export or the equivalent CAD command and select STEP (*.step, *.stp).
8. Reopen the STEP file in the target CAD system and check units, bounding-box dimensions, body count, critical holes, interfaces, and solid-integrity status.

SAT is preferable to OBJ for this workflow because it is an ACIS solid-model exchange format. OBJ is a polygon mesh; converting an OBJ to STEP usually produces faceted surfaces or a low-quality imported body, not the precise B-rep geometry expected from a mechanical CAD file. Revit add-ins advertised as direct STEP exporters can remove the SAT step, but they must support the installed Revit release and produce valid B-rep solids rather than a mesh.

Online and alternative tools

For a nonconfidential SAT file, CAD Exchanger Web may provide SAT-to-STEP conversion when both formats are listed as available for the current service and account. Upload the exported .sat, choose STEP as the output, download the result, and validate it in the destination CAD system. Online services generally do not accept arbitrary RFA files because interpreting Revit family geometry requires Revit or a compatible Revit reader.

Do not upload proprietary building, product, or client data to an online service without approval. For confidential files, perform the Revit-to-SAT-to-STEP workflow locally with Fusion, Inventor, or another CAD application that supports both formats.

Quality and compatibility limits

The result normally preserves visible 3D geometry only. Family parameters, formulas, constraints, reference planes, connectors, materials, BIM metadata, symbolic geometry, view-specific detail, and nested-family relationships can be discarded.

Set and verify units at export and import. A unit mismatch can scale a model by 25.4, 0.03937, or another conversion factor. SAT and STEP may carry unit information, but software import settings and ambiguous source units can still cause incorrect scale.

Complex Revit geometry may export as multiple solids, open shells, or failed faces. Suppress unnecessary hardware and fine detail before export, then verify the STEP file with section views, measured dimensions, a bounding-box comparison, and the receiving application’s geometry or solid check. A STEP file is an imported CAD model, not a reversible substitute for the original RFA; retain the RFA when future parameter changes or BIM editing are required.