3MF to STL Converter — Local Parts & Unit Check
Convert 3MF to real binary STL locally. Preserve supported part transforms, check millimeter dimensions, select mesh instances, and download a separate-parts ZIP with a clear loss report.
3MF Studio
Local conversion with explicit limits. Keep your original 3MF.
Supported scope: 32 MiB input · 100,000 triangles · 128 mesh instances
Your 3MF package
Required fields are marked with an asterisk.
Geometry, parts and conversion losses
Review your output, then save it to your device.
Make the next step clear.
Your findings, assumptions and next steps will appear here after you run the check.
3MF Studio · https://threemf.kitforma.com/ · KitForma
Real binary STL and separate-part ZIP
Millimeter dimensions and supported nested transforms
Local files, selectable parts and an explicit loss report
Understand the evidence.
Focused guides explain the rules, the edge cases and the checks worth doing before you act.
Convert 3MF to STL without losing the scale
Read the source unit, export millimeter coordinates, and verify a known dimension before printing.
Read the guide ↗Field guide / 02Export separate 3MF parts with their placement intact
Understand mesh instances, nested assemblies and the difference between a combined STL and a Boolean union.
Read the guide ↗Field guide / 03What a 3MF to STL conversion keeps and loses
Use the loss report to decide whether a geometry-only copy is suitable for the next application.
Read the guide ↗Before you start
Are my 3MF files uploaded?
No. ZIP decoding, XML parsing, geometry transforms, previews and exports run on your device. Product analytics do not receive the file, its contents or its filename.
Does STL keep the colors and printer settings?
No. STL contains geometry only. The report records exported instances and explains losses; it does not preserve the original color/material assignments or slicer settings. Keep your original 3MF.
Will my parts keep the right size and position?
Supported Core units are converted to millimeter coordinates. Nested component and build transforms are applied, including reflection-aware face order. Import the resulting STL as millimeters and keep assembly placement in your receiving application.
Can I download just one part?
Yes. Choose numbered instances in the form, or use the preview checkboxes and its selection download buttons. The ZIP contains one STL per selected mesh instance. Repeated uses of the same mesh remain separate instances.
Does this support every slicer project or repair broken meshes?
No. It is a bounded Core/Production geometry converter, not a full slicer or repair service. Unknown required extensions, unsupported helper geometry, external references, mixed-unit model parts and unsafe or oversized files are refused. Slicer-specific plate and modifier semantics are not reconstructed.
What are the limits?
32 MiB compressed, 96 MiB expanded, 24 MiB per ZIP entry, 3,000 entries, 128 mesh instances, 100,000 source or expanded triangles and 32 nested levels. Transformed coordinates must remain within ±10,000 mm. Zero-area or float32-collapsed faces are rejected.
Sources & assumptions
Formats, algorithms and supported features are documented below. Check the stated scope and inspect your output before using it.
- 3MF Consortium specifications ↗
Core model units, packages, resources and published extensions.
- 3MF Core specification ↗
Authoritative Core XML model and geometry specification.
- Prusa: exporting from a slicer ↗
STL export and the distinction between geometry and a saved project.
- Prusa: saving projects as 3MF ↗
Project settings and data that a geometry-only export cannot retain.
Reviewed 2026-10-17. Read our methodology or report an issue.