Convert STEP to 3MF
Convert STEP to 3MF locally in your browser. The selected file is not uploaded. Check the output report for reader and writer limitations.
Control how CAD surfaces become a mesh. Your file stays in your browser.
Supported output and limits
Supported output
- A mesh imported from supported CAD geometry
- An output unit declaration in millimetres
- Supported flat part colours
Limits and checks
- Rounding can change positions and topology; watertightness is not guaranteed
- Texture images, UV coordinates, animation and rigs are not exported
- Per-vertex colour variation is not exported
- Preparation exports bake scene transforms into each mesh instance; original hierarchy and shared instancing are not preserved
- Exact CAD curves, surfaces and native design history are not retained
- Point geometry is unsupported by this writer
↺ the reverse: 3MF → STEP · about .step · about .3mf · just view it instead
When to convert STEP to 3MF
Prepare a CAD part for printing when the receiving slicer accepts 3MF and a recorded output unit is useful.
Availability and file handling
This page uses the adjustable tessellation preparation tool. Its limits are 25 MiB, 200,000 triangles and 1,000,000 vertices. Worker operations stop after 45 seconds and can be cancelled. Files stay in this browser; there is no hosted fallback. Preparation exports bake scene transforms into mesh positions and check coordinates, dimensions and topology after readback. These checks do not establish manufacturing suitability.
What this implementation exports
- A mesh imported from supported CAD geometry
- An output unit declaration in millimetres
- Supported flat part colours
What needs checking
- Rounding can change positions and topology; watertightness is not guaranteed
- Texture images, UV coordinates, animation and rigs are not exported
- Per-vertex colour variation is not exported
- Preparation exports bake scene transforms into each mesh instance; original hierarchy and shared instancing are not preserved
- Exact CAD curves, surfaces and native design history are not retained
- Point geometry is unsupported by this writer
The CAD reader uses the linear and angular deflection settings selected in the tool. Requested deflection is separate from measured surface error. The example cylinder provides an independent analytic comparison; another model needs its own reference.
Size and units
Check one known dimension after opening the output in its destination application. A one-inch length is 25.4 millimetres; interpreting a coordinate value of 1 as millimetres makes that length 25.4 times smaller. Assigning units to a unitless file requires a known reference or information from its author.
What the test result establishes
The recorded core matrix checked this pair against 44 sample files on 2026-09-07. Those fixture results do not guarantee success for every file, prove manufacturing suitability, or establish a public route. Output readback failures must remain visible; a file being parseable does not prove equivalent geometry.
Keep the source
Keep the original STEP file. Exporting it as 3MF does not make the process reversible: a later conversion cannot recover information omitted by a reader or writer. For an existing model, compare dimensions, components and any required colours before replacing a working file.