A Bambu Studio project with two plates
Saved by Bambu Studio itself, with a modifier and a negative part on plate 1 and another part on plate 2. Only the printing part of plate 1 goes into the STL.
Free 3MF to STL converter
Drop a 3MF and see what is inside it before you convert: which plate each part sits on, which volumes are modifiers or negative parts, and what unit the file uses. Then export one plate as an STL. The file never leaves your browser.
Drag and drop a 3MF file here, or
Accepts .3mf, including Bambu Studio, OrcaSlicer and PrusaSlicer projects. Nothing is uploaded.
Saved by
Unit in the file
Parts on this plate
This plate has a negative part. This converter leaves it out but cannot cut the hole, so the body in the STL is solid where the designer wanted a hole. To keep the hole, open the file in Bambu Studio, use File, Export, Export all objects as one STL, and answer Yes when it offers a mesh boolean.
A mirrored part was found; its faces were turned the right way out.
Output size
Mesh check
Checked in your browser. Nothing is uploaded.
The file is read and converted on your device. It is never uploaded to a server.
Try it on a real file
A PrusaSlicer project
PrusaSlicer keeps every volume in one mesh and records which triangles belong to which. They are separated and labelled the same way.
A 3MF saved in inches
The unit is read from the file and converted, so a 1.575 inch box comes out as 40 mm. Four of the nine converters we tested missed this.
What it reads that other converters miss
Plates
A slicer project can hold several plates. You choose one, so plate 2 does not end up in the same STL as plate 1.
Parts that do not print
Modifiers, negative parts and support blockers are listed with what they do and left out by default, instead of turning into solid blocks.
Units
3MF records its unit. Inch and centimetre files are converted, so the STL is the size the designer meant.
We tested nine 3MF to STL converters on files with known right answers. On a two plate Bambu Studio project, every one of them that opened the file also exported the part from the other plate, and five turned the modifier and negative part into solid blocks. This one reads the slicer project data that decides what should print, so it can list it and leave it out. Read the test of nine converters · See the results table
What it does not do
- No holes cut. It does not cut negative parts into the body. That needs a mesh boolean; it tells you when a plate has one.
- No colour or settings. It does not carry colour, painted supports or print settings. STL has no field for any of them.
- Positions kept. It keeps the positions from the file. Slicers usually place an imported STL on the bed for you.
Questions
Is my file uploaded anywhere?
No. The 3MF is unzipped and read by code running in this page, and the STL is written in the same place. Nothing is sent to a server.
Why does the converter show parts I did not see in the slicer as separate objects?
Slicer projects store modifiers, negative parts and support blockers as extra volumes inside an object. The slicer draws them as helpers; in the file they are just more triangles. They are listed here so you can see them, and they are left out of the STL unless you tick them.
My 3MF has several plates. Can I get all of them in one STL?
Choose "All objects" in the plate list. Bear in mind that Bambu Studio places each plate beside the previous one, so the parts from plate 2 sit about one bed width to the right of plate 1 in the file.
Why will my Bambu 3MF not open in PrusaSlicer, when it opens here?
PrusaSlicer rejects a Bambu project that contains a modifier or negative part, because Bambu writes those as a kind of object the 3MF specification does not allow a printable object to reference. This page reads Bambu's own project data instead, so it can tell those parts apart.