The limit: MakerWorld
- File size cap
- 150 MB
- Triangle cap
- no fixed cap
- Triangles at that size
- 3.15 million
This page opens the reducer at 140 MB. Source: Bambu Lab forum, MakerWorld upload limits (checked 2026-09).
Why the file is over it
Print profiles bundle the model with plate layout and settings, so the STL is not the only thing counted. Models that come from a scan, a sculpt or Bambu Studio's mesh boolean can carry 3 to 6 million triangles; at 50 bytes each that is 150 to 300 MB before anything else is added. The forum threads on this limit are mostly people with exactly that kind of file.
How to get under it
- 1Drop the STL below. The target is preset to 140 MB; lower it if the profile has several plates.
- 2Press Reduce. Flat areas lose triangles first, so the printed surface changes far less than the number suggests.
- 3Read the result card. It shows the new size and whether the mesh is still watertight.
- 4Download, place it in Bambu Studio, and upload the profile.
What to expect
A 220 MB scan (about 4.6 million triangles) reduced to 140 MB keeps 2.9 million: at the resolution of a 0.4 mm nozzle the difference is not printable. Going to 60 MB still leaves 1.25 million triangles and uploads faster; most figures and busts look identical at that level.
Other ways
Bambu Studio has Simplify Model in the right-click menu, which works but gives no size target and can make curved surfaces look faceted at aggressive settings. Splitting the design across several profiles avoids the per-profile cap but not the 250 MB raw model total.
Questions
Is the limit 150 or 200 MB?
Bambu raised the per-profile limit to 200 MB in March 2024; older guidance and some regions still show 150 MB. Aim under 150 MB and you are safe either way.
Does the 250 MB total include the 3MF?
It counts the raw model files attached to the design. The 3MF you export from Bambu Studio contains the meshes, so a lighter STL makes the 3MF lighter too.
Will reducing change how supports generate?
Only where the surface actually changes. Overhang angles are preserved because decimation merges triangles along the existing surface rather than smoothing it.