3MF to STL for PrusaSlicer, with no upload
PrusaSlicer reads 3MF, but plenty of workflows still need a flat STL first. This is the fastest route from a 3MF to a PrusaSlicer-ready mesh — entirely in your browser.
Drop .3mf files here
or drag & drop — up to 150 MB each, multiple files supported
Why flatten 3MF to STL for PrusaSlicer
PrusaSlicer opens 3MF directly, so the honest answer is: you do not have to convert. But there are three situations where a flattened STL is the better artefact.
- You will move the model. STL is the common denominator; a hand-off to Bambu Studio, Cura or a print farm stops being a compatibility question.
- You want multi-body assemblies in one mesh. A flattened STL has no build tree to disagree about — every part is baked at its correct transform.
- You need repair first.PrusaSlicer's fix tools work on a mesh you can inspect; converting to STL first gives them a clean input.
Convert 3MF to STL in three steps
- Drop the 3MF. One model or a whole queue — the converter reads the ZIP, unpacks the meshes and resolves the build tree locally.
- Keep binary STL. PrusaSlicer loads binary fastest; it is roughly five times smaller than ASCII for identical geometry.
- Save and import. Add the STL to PrusaSlicer. Parts keep their relative positions, so nothing needs re-placing.
The problems people actually hit
- Model lands off the bed. STL has no unit tag, so PrusaSlicer assumes millimetres. If the model is off, it is a scene-scale setting — the coordinates came through 1:1.
- Holes in the surface. Real gaps in the source mesh. Fix them upstream in Fusion 360, Blender or tinkercad, then convert.
- “File too large”. Over the 150 MB ceiling per file. Re-export without textures or split the assembly.
Worth knowing: nothing is uploaded. Everything is parsed by JavaScript on your machine, so a confidential print job never reaches a server. For the full list of failure modes, see the 3MF to STL troubleshooting hub.
Related routes
Comparing slicers? Check the Cura route, the Bambu Lab route, or the binary vs ASCII explanation.
Frequently asked
Why convert 3MF to STL for PrusaSlicer at all?
PrusaSlicer reads 3MF, but STL is the most portable format and the safest input for repair tools — especially when the model will travel to another slicer or a print farm.
Will multi-object 3MF stay aligned?
Yes. Nested components and each item's 4×4 transform are resolved before flattening, so parts sit where the designer put them instead of piling at the origin.
PrusaSlicer reports holes in my converted model — why?
Those are genuine gaps in the source geometry; conversion cannot invent triangles. Repair the mesh upstream or run PrusaSlicer's fix on the STL.
Is there a file size limit?
150 MB per file to keep the tab responsive. Re-export without textures or split the assembly, then convert each part.