The limit: Blender
- File size cap
- no fixed cap
- Triangle cap
- no fixed cap
- This page opens the reducer at
- 25 MB
This page opens the reducer at 25 MB. Source: Blender manual, Decimate modifier (checked 2026-09).
Why the file is over it
Sculpting needs dense geometry to hold detail while you work, and the STL exporter writes every triangle at whatever level is active. Applying the multires modifier at its top level before export is the usual mistake. Blender also happily exports non-manifold results from booleans and Dyntopo, which slicers refuse.
How to get under it
- 1Export from Blender as binary STL (the default) at full detail, then drop it below. The target is preset to 25 MB.
- 2Press Reduce. Quadric collapse keeps sculpted creases; smooth expanses give up their triangles.
- 3Read the result card, including the repair notice: it lists non-manifold edges separated and degenerate faces removed.
- 4Download. The file is print-ready; re-import into Blender if you want to compare.
What to expect
A 240 MB sculpt (5 million triangles) to 25 MB keeps 525,000 triangles. On a 150 mm bust that is a triangle every 0.12 mm, finer than a 0.2 mm layer. Compared with Decimate at ratio 0.1 the result is similar in count and the surface is slightly smoother, because the collapse order is driven by curvature rather than a global ratio.
Other ways
Decimate (Collapse mode) inside Blender is the closest equivalent; set the ratio, apply, export, check the size, repeat. Its Planar mode is better for CAD-like meshes. The Remesh modifier rebuilds the surface and loses sharp detail; avoid it for size reduction.
Questions
Should I export ASCII or binary STL from Blender?
Binary, always: ASCII is about five times larger. The reducer writes binary regardless.
Does the reducer respect my sculpted detail?
It keeps triangles where curvature is high and removes them where the surface is flat, which is where sculpted detail lives. Fine skin texture below the print resolution is the first to go.
Can I reduce before applying multires?
Export at the level you want to print, then reduce. Exporting a lower multires level loses detail everywhere; reducing removes it only where it does not show.