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STEP to 3MF converter

Drop your .step / .stp file — we convert it to .3mf right in your browser. Files never leave your computer.

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Drop your STEP file here
Accepts .step / .stp · converts to .3mf

STEP vs 3MF— what's the difference?

STEP.step / .stp

ISO 10303 boundary-representation CAD format — the industry standard for exchanging precise, parametric solid models between engineering tools.

Strengths
  • Exact curved surfaces (NURBS / B-rep) — no tessellation loss
  • Assembly hierarchy, part names and metadata preserved
  • Supported by every major MCAD tool (SolidWorks, Inventor, Fusion, Creo, NX…)
  • Open, vendor-neutral ISO standard
Limitations
  • Not directly consumable by 3D printers or game engines
  • Files are larger and slower to open than mesh formats
  • Requires a CAD kernel to read — no native browser support
Typical use: Engineering CAD exchange, mechanical design, supplier handoff
3MF.3mf

Modern successor to STL for 3D printing — carries units, colours, materials, and multiple bodies in a zipped XML package.

Strengths
  • Real-world units baked in (no more "is this mm or inches?")
  • Multi-material, multi-colour, and per-body metadata
  • Compact zipped payload — smaller than equivalent STL
Limitations
  • Not every slicer reads 3MF yet (most do now — Bambu, Prusa, Cura)
  • Less tooling for mesh editing compared to STL
Typical use: Modern 3D printing workflows, multi-material prints

How to convert STEP to 3MF

  1. 1
    Drop a .step or .stp file. The browser tessellates the CAD B-rep via OpenCascade (WASM) locally.
  2. 2
    Preview the generated mesh in 3D and verify the triangle count is acceptable for printing.
  3. 3
    Click Download .3MF. Load directly in Bambu Studio, PrusaSlicer, Cura, or OrcaSlicer.

FAQ

Why convert STEP to 3MF?

STEP carries exact CAD geometry but no slicer can print it directly. 3MF is the modern mesh format every current slicer prefers. This page tessellates the STEP into triangles and packages them as a units-aware 3MF — one step instead of STEP → STL → load-into-slicer.

What tessellation quality is used?

We use OpenCascade defaults (linear deflection tuned for visual fidelity). For most PCB-component and mechanical parts this gives sub-0.1 mm surface error, which is below any FDM layer height.

Are units preserved?

Yes — STEP mandates millimetres, and 3MF stores units explicitly. The output will load at the correct real-world scale in every slicer.

Do I still need a STEP viewer?

If you just need a print, no — drop STEP, get 3MF, slice. If you need to machine the part (CNC/mill), keep the STEP; mesh formats lose the B-rep a CAM tool needs.

Is anything uploaded?

No. OpenCascade runs entirely in WebAssembly inside your browser. The STEP file never leaves your device.

Related converters

STEP → STLSTEP → OBJSTEP → GLBSTEP → USDZSTL → 3MF