Convert STL to 3MF to put an existing triangle mesh into a structured package with explicit millimeter units. Choose how to interpret the source coordinates, inspect the resulting size and download a valid manufacturing-format archive. This is geometry packaging for an existing surface, with all processing inside your browser.
Use STL to 3MF to hand a unitless prototype to a collaborator with its intended scale declared. For an inch-based accessory, select Inches before opening, then check the millimeter preview against a known dimension. This avoids relying on the recipient’s default unit assumption.
The downloaded package carries geometry and units, so your collaborator still chooses printer and material settings. No account or monthly allowance is needed. Save the package before navigating away.
Set STL input unit to Millimeters (mm) or Inches (inch), using the design's known convention. STL does not record that information. Then select Open STL or drop an ASCII or binary mesh into the preview. Changing units clears the model; reopen to apply.
Check Width X, Depth Y and Height Z, which are always displayed in millimeters. Use Fit model to view for an overview. In this STL to 3MF workflow, inch input multiplies each coordinate by 25.4 before preview and export; it does not merely attach a different label.
Select Download 3MF to write the archive. Open the downloaded file in a compatible application and compare its dimensions and triangle count. The STL to 3MF writer creates one mesh object and one build item, even when the source contains multiple disconnected shells. Keep the original STL.
A genuine STL to 3MF export contains an OPC content-type manifest, root relationships and a model XML part. The model declares millimeter units, lists vertices and triangle indices, defines one object resource and places that object in the build. Renaming a filename cannot create any of this structure.
Repeated vertices with identical numeric coordinates share a single vertex entry. Deduplication preserves triangle connections. ZIP compression then packages the XML files. Smaller downloads are not guaranteed.
The writer retains the source triangle arrangement. It cannot recover curves or CAD history. Multiple shells remain within the one exported mesh object. Prepare separately selectable assembly objects in another application.
STL describes a triangulated surface using coordinates with no standard unit declaration. 3MF can express units, resources and richer manufacturing information. This STL to 3MF tool adds a valid container and an explicit scale convention, but source triangles alone cannot supply missing colors, material assignments or printer profiles.
An exported package is therefore a geometry document rather than a complete slicer project. Choose printer, layer, support and material settings in your slicer. Packaging a model does not make an open surface solid, improve a coarse curve or establish a successful printing orientation.
This STL to 3MF converter cannot recover metadata absent from the source, repair holes, assign multiple materials or split shells into separate objects. It accepts one file at a time, up to 25 MiB and 400,000 triangles. Generated model XML is limited to 64 MiB, and the final package to 25 MiB. Invalid coordinates and incomplete meshes are reported rather than wrapped into a misleading download.
No. The input surface has no reliable source for those properties. Set colors, materials and printer configuration in an application that supports them after importing the package.
Choose the convention used to create the STL. If that is unknown, compare a known physical dimension first. Inch input is converted to millimeters rather than stored as an inch-unit model.
Yes. Both encodings are parsed as real triangle geometry. The resulting archive uses indexed model XML, not an embedded STL with a different extension.
No. Identical vertices are deduplicated, but triangle count is retained. Mesh simplification and geometric repair are separate operations outside this converter.
Use the reverse converter to read the package and compare its dimensions. Binary STL output introduces normal 32-bit coordinate rounding, so allow small numeric differences.
No account is required and no cloud project is created. Save the download locally and reopen your source if you want to repeat the conversion in another session.