Convert 3MF to STL free in your browser. The file’s units set the size, multi-part plates import as named parts, and you export a print-ready STL.
Drag your .3mf file into OwlCAD in your browser, then click Export and save it as STL. The parts arrive at their true size, and there is nothing to install.
A 3MF can hold a whole plate. Check, rearrange or drop parts, then export.
3MF records its units, so the model arrives at its real size in millimetres.
A multi-object 3MF imports as separate, named parts in their own colours, so you can move, hide or delete one before exporting.
The import checks the mesh for holes, and Repair closes them before you export.
Drop the file on the build plate, check the parts, and export an STL for your slicer.
It opens on your device, it is saved to your workspace as you work, and it exports back out in the format your slicer wants.
Your browser reads and renders the model itself, so it appears as soon as you drop it in — you are never queued behind anyone else’s upload, and the file does not travel anywhere before you can see it.
Most online viewers forget your file the moment you close the tab. OwlCAD keeps the model in your own workspace and syncs it as you work, so it is still there when you come back to this browser. Create a free account and it follows you to any device, and your projects dashboard lets you delete anything you no longer want.
When you are done, export STL, 3MF, OBJ, GLB or STEP — the format your slicer or your colleague actually needs, not a project file that only opens here.
Each object imports as its own named part. Export STL writes every visible part into one file, because STL has no idea of separate objects; export 3MF instead to keep them apart.
Not in the STL, which stores geometry only. The colours arrive in OwlCAD and survive a 3MF export, and you can also export one file per colour for a printer without a multi-material unit.
No. A 3MF states its unit, so the model keeps its size in millimetres, and the STL carries those numbers. Slicers read an STL as millimetres.
Yes. Importing, editing and exporting in OwlCAD is free, and you can start without an account. AI generation is the optional Pro upgrade.