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3MF File Compressor

Reduce a 3MF to the size you need and get a 3MF back. Only the mesh triangles change: plates, slicer settings, thumbnails and colour regions stay exactly as they were.

📉
Drop a 3MF file here or click to browse
Up to 300 MB · 3MF (.3mf)
Choose 3MF file
Or drop several files at once: 3 on the free plan, up to 25 with a Day Pass or Pro.
1
Upload 3MF
2
Set target MB
3
Download
MB
1 MB500 MB

We aim for exactly this size. Quality-preserving quadric decimation stops as soon as the file fits. If the mesh cannot be reduced further without breaking, we return the smallest safe result.

Pick a 3MF file to continue.
🔒 Files are processed on our server in isolated memory and removed within 15 minutes of your download.
Server-sideProcessed on our server, then deleted

Your file is uploaded to our server to be processed, so it does leave your device. Temporary files are removed as soon as processing finishes, and the uploaded original is deleted automatically within 120 minutes at the latest. Nothing is stored permanently.

About

A Bambu Studio or PrusaSlicer project grows fast: a detailed figure, a multi-plate build or a four-colour print can push the .3mf past 100 MB, and MakerWorld refuses uploads over 150 MB. The usual advice, export an STL and decimate it, throws away the plates, the filament assignments and every setting you tuned. This page reduces the 3MF itself: set a size in MB, drop the project, and you get a .3mf back that opens in the same slicer, on the same plates, with the same settings, only lighter.

Why it is big in the first place: a 3MF is a ZIP package, and the meshes inside are XML with a line for every vertex and every triangle. The package is already compressed, so zipping it again gains nothing; the size is in the triangle count. That is the one thing this tool changes. Slicer project settings, plates, thumbnails, object transforms, units and every other file in the package are copied byte for byte; only the mesh parts are rewritten, along with the triangle counts Bambu Studio and OrcaSlicer keep in their metadata.

Colour and material regions are reduced one by one, so the border between two filaments stays where it was and one colour does not bleed into its neighbour. The geometry goes through the same quadric decimation as the STL Compressor, which keeps sharp edges and small text while flat areas give up their spare triangles. Files from Bambu Studio, PrusaSlicer, OrcaSlicer and Cura are supported; a painted multi-colour Bambu project cut to a tenth of its triangles still sliced with filament use within 0.3 percent of the original.

Painting is handled with care. Triangles that the slicer subdivided for multi-material, support or seam painting are locked and kept exactly; regions painted in one colour are simplified only inside the region; objects painted in PrusaSlicer's JSON paint format are passed through unchanged. The reduction runs on a native C++ engine on our server and lands between 98.5 and 100 percent of your target. Uploads up to 300 MB go up in chunks and are deleted within 15 minutes of your download, at most 120 minutes otherwise. One 3MF up to 50 MB a day is free, and paid plans are shared with the STL tools.

How it works

  1. 1Drop your .3mf project or model (up to 300 MB) on the upload area.
  2. 2Set the size you need in MB, for example under an upload limit.
  3. 3Start the reduction; only the mesh triangles are reduced.
  4. 4Download the .3mf, open it in your slicer and check painted areas before printing.

FAQ

›Will my plates and slicer settings survive?
Yes. Only the mesh triangles change. Project settings, plates, thumbnails, object transforms, units and every other file in the package are copied byte for byte, and the triangle counts in Bambu and Orca metadata are updated, so the project opens as you saved it.
›My 3MF is too big for MakerWorld. Will this get it under?
Set the target a little under the 150 MB limit, for example 140 MB, and upload the project. The plates, settings and colours stay, so the upload still shows your print profile.
›Will the colours bleed into each other?
No. A multi-material or multi-colour model is reduced region by region, so the border between two filaments stays a border and each region keeps its own material.
›What happens to painted supports, seams and multi-material painting?
Detailed painting survives exactly: triangles the slicer subdivided for painting are locked and not reduced. Areas painted in a single colour are simplified only within that colour, so borders stay sharp. Objects that use PrusaSlicer's JSON paint format are left as they are.
›A 3MF is already a ZIP. Why does zipping it again not help?
Because the size is in the mesh, not in the packaging. The XML inside lists every vertex and every triangle, and the ZIP is already compressed; only fewer triangles make the file smaller.
›Which slicers' files work?
3MF files from Bambu Studio, PrusaSlicer, OrcaSlicer and Cura. Slicer-specific files in the package are carried over as they are.
›How close to my target does it land, and what does it cost?
Between 98.5 and 100 percent of the target; if even the smallest intact version is bigger, you get that and the result screen says so. One 3MF up to 50 MB a day is free, and paid plans are shared with the STL tools.