Fusion 360 Export Formats Explained: STEP vs F3D vs IGES vs SAT vs USD

All formats at a glance

STEP — the universal CAD format

STEP (ISO 10303) is the closest thing CAD has to a universal language. Every serious CAD, CAM, and inspection package can open it: SolidWorks, Inventor, FreeCAD, Onshape, Creo, NX, CATIA, and every online manufacturing service.

What it preserves: exact solid and surface geometry (BREP), assembly structure, and part names. What it loses: your parametric timeline, sketches, and features — a STEP file is "dead" geometry that can be measured and machined but not easily edited parametrically.

Use STEP when: sending parts to a machine shop or 3D-printing service, sharing with anyone on different CAD software, or keeping a vendor-neutral copy of your work.

F3D / F3Z — Fusion Archive

The Fusion Archive is Fusion 360's native export. It contains everything: the parametric timeline, sketches, parameters, joints, bodies, components, and settings. Re-importing an F3D restores the design exactly as it was saved.

The two extensions are the same format in practice: .f3d holds a single self-contained design; .f3z is produced automatically when a design references external components, bundling the whole set so the assembly survives the round trip.

Use F3D/F3Z when: backing up your library (see our local backup guide), moving designs between accounts or hubs, or archiving finished projects in full fidelity.

IGES — legacy interchange

IGES predates STEP by decades. It still shows up in requirements from older CAM systems, inspection software, and some analysis tools, but it's a less robust format — IGES transfers surfaces rather than watertight solids, and imports often need healing.

Use IGES only when the recipient explicitly asks for it. If they can take STEP, send STEP.

SAT — ACIS solids

SAT is the native format of the ACIS geometric modeling kernel. Software built on ACIS (some CAM, mold design, and simulation tools) imports SAT files losslessly. Outside that ecosystem, STEP is the safer bet.

SMT — Autodesk Shape Manager

SMT is the format of Autodesk's own Shape Manager kernel — the geometry engine behind Fusion and Inventor. It's mainly useful for high-fidelity transfer into other Autodesk products. If your workflow stays inside Autodesk tools, SMT preserves geometry exactly; otherwise you'll rarely need it.

USD — for AR, VR and visualization

USD (Universal Scene Description, exported as .usdz) is a 3D scene format from the film/VFX world, now the standard for AR content — it's what Apple's AR Quick Look uses on iPhone and iPad. Export USD when you want to drop a design into an AR preview, a rendering pipeline, or a game engine, rather than another CAD tool.

PDF — drawing documentation

PDF export applies to Fusion drawing files (.f2d), not 3D models. It produces the 2D sheets — dimensions, tolerances, title blocks — that machinists and clients actually read. If you maintain drawings for your parts, batch-exporting them to PDF is usually part of every release. We cover that workflow in How to Bulk Export Fusion 360 Drawings to PDF.

Which format should you choose?

• Sending parts to a manufacturer: STEP (plus PDF drawings if you have them).
• Backing up your library: F3D/F3Z primary, STEP as the vendor-neutral insurance copy.
• Sharing with other CAD users: STEP, unless they're also on Fusion — then F3D keeps the history.
• Legacy CAM/inspection requirement: IGES or SAT, per the recipient's spec.
• AR preview or rendering: USD.

Often the right answer is "several at once" — F3D + STEP for backups, STEP + PDF for manufacturing releases. Natively, that means exporting each file multiple times. A bulk exporter like ExportKit Pro opens each design once and writes every selected format before closing, so adding a second or third format costs almost no extra time. The complete bulk export guide walks through the whole workflow.