Convert STEP
to 3MF.

Updated 2026-10-19

To convert STEP (.step / .stp) to 3MF (.3mf), drop the file below and download the result, in the browser with nothing installed. The exact surfaces are triangulated into a 3MF mesh.

5 conversions a day with no account. No card, no install. In your browser: no daily limit, and the file is never uploaded.

No account needed
Drop a STEP file.step / .stp · up to 200 MB

On our servers. No account: deleted within 24 hours. Signed in: kept until you delete them. Never shared or used for training.

ResultTessellated

Edges are sampled first, so chamfers, fillets and holes come through crisp. Default tolerance: 0.02 mm chord deviation, 0.1 rad angle — fine enough to print directly.

Tessellation is one-way — keep the STEP file if you will edit the shape later.

HowThree steps
  1. Drop your .step file above — up to 200 MB without an account.
  2. 3MF is already selected as the output.
  3. Download the .3mf. Without an account, files are deleted within 24 hours; signed in, they are kept until you delete them.
FormatsWhat you are holding

STEP file (ISO 10303) (.step / .stp)

STEP (ISO 10303) is the closest thing engineering has to a universal solid format. It stores exact B-rep geometry — a hole is a cylindrical face, not a ring of facets. Fusion 360, Inventor, Onshape, SOLIDWORKS, Creo, NX, CATIA and FreeCAD all read it; .step and .stp are the same format. AP242 supersedes AP203 and AP214.

What you send when the other side has to keep modelling, quote machining, or open the shape in a different CAD system.

3D Manufacturing Format file (.3mf)

3MF was designed to replace STL for 3D printing. It records units, colour and material, keeps multiple objects separate, and is compressed. Bambu Studio, PrusaSlicer, Cura and Windows all read it. The shape is still a triangle mesh.

You are printing and want units, colour and part structure to survive the handover.

Questions5 answered
Is the STEP to 3MF converter free?
Yes. 5 conversions a day with no account and no card. A free account raises the limit and adds 25 credits. Choose In your browser instead and there is no daily limit at all.
How accurate is the 3MF mesh?
The exact surfaces are triangulated into a 3MF mesh. Edges are sampled first, so chamfers, fillets and holes come through crisp. Default tolerance: 0.02 mm chord deviation, 0.1 rad angle — fine enough to print directly. Tessellation is one-way — keep the STEP file if you will edit the shape later.
How big a file can I convert?
To a mesh format like STL: 300 MB with a free account, 200 MB without one. To STEP, Parasolid or SLDPRT: 140 MB, because rebuilding a solid takes about twice the memory of writing a mesh. Maker and Studio convert up to 830 MB and 380 MB — a large conversion on a paid plan gets the server to itself.
Is it safe to upload my STEP file?
Files travel encrypted and are processed by machine on our own servers — no third parties, no ads or trackers, no AI training. Or skip the upload: choose In your browser above the drop zone and this conversion runs on your own device, so the file never leaves it.
Is my STEP file deleted after converting?
Without an account, the upload and the result are deleted within 24 hours. With an account, both stay in your files until you delete them; deleted files leave our servers within 24 hours.
Beyond convertingSame file, four workspaces

Keep the part open: fill it with a lattice, check it with FEA, texture a surface, or slice it into cut-ready sheets. These workspaces are in early access — create an account, then apply from inside the app.

Create free account See pricing

ReadWhy this works the way it does
AlsoOther ways in
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Going the other way? Convert 3MF to STEP.