Why is my STL tiny in PrusaSlicer?

The mesh has no reliable unit field. A design exported in metres becomes 1000× smaller when a slicer treats the numbers as millimetres. Check the bounds here, then fix the unit at export time.

Does PrusaSlicer repair STL files automatically?

PrusaSlicer can attempt repairs, but complex holes, self-intersections and non-manifold edges may remain. A local clean or full repair before import gives a more predictable result.

Why does my object have no layers in PrusaSlicer?

The mesh may be open, have zero volume, be positioned below the bed or be too small for the current layer height. Check triangle count, bounds and boundary edges before changing the profile.

Can PrusaSlicer import OBJ and 3MF files?

Support varies by version and build. STL remains the most portable option, but a clean 3MF or OBJ can work when the exporter writes a standard mesh. Verify the imported dimensions after loading.

What does this local check change in my file?

Nothing. The checker reads the file and reports diagnostics only; it does not modify the original or upload it. Use the linked repair tools if you want to create a new cleaned file.

Slicer import fixes

PrusaSlicer model not showing? Diagnose the STL locally

PrusaSlicer is strict about files that cannot be turned into a closed volume. A model that imports but produces no layers, a 200 mm part that appears 0.2 mm wide, or a repair that never finishes all point to different file problems. Use this page to inspect the actual geometry, units and topology before changing the slicer profile or trying another download.

PrusaSlicerNo uploadSlicers · Windows / macOS / Linux

Typical symptoms

The object appears in the list but the plater stays empty or shows no layers.
PrusaSlicer reports an import error or says the file is not a valid STL.
The object is 10, 25.4 or 1000 times larger or smaller than expected.

File import check

No upload

PrusaSlicer

The detected signature, bounds and topology are reported locally. These are triage signals, not a slicer validation.

File checks

The detected signature, bounds and topology are reported locally. These are triage signals, not a slicer validation.

Detected file signatureBoundary edges · Non-manifold edgesTypical symptoms

Drop the file that won't open

STL, OBJ, PLY, 3MF, GLB, glTF, or a .gltf with its .bin companions. The file is read locally.

Choose a file

Max file size: 500 MB · No upload

No upload · Worker

Typical symptoms

The object appears in the list but the plater stays empty or shows no layers.
PrusaSlicer reports an import error or says the file is not a valid STL.
The object is 10, 25.4 or 1000 times larger or smaller than expected.
The repair dialog runs for a long time, then leaves a mesh with holes or non-manifold edges.

Common causes

The STL header disagrees with the file length

PrusaSlicer reads the declared triangle count in a binary STL. A truncated download or a text file renamed to .stl fails before the slicer can show the model.

The mesh has no closed volume

A surface with boundary edges can import, but it cannot be sliced as a solid. Large holes and inconsistent winding produce empty layers or unexpected repair failures.

The object is hidden or empty in the source scene

Some exports contain only a camera, an annotation or an empty mesh node. The file is readable, yet there are zero triangles for PrusaSlicer to place on the bed.

Units and transforms were baked in incorrectly

STL has no unit field and OBJ units are ambiguous. A metre-based CAD export becomes 1000× small, while an inch-based export is 25.4× large unless the scale is corrected at export.

Export checklist

1
Export binary STL or 3MF in millimetres and verify the triangle count is greater than zero.
2
Close the mesh in CAD and apply all object transforms before exporting.
3
Avoid saving a web page or an error response under an .stl filename.
4
If the source is a 3MF project, export a fresh archive rather than editing its ZIP contents by hand.

How it works

1
Drop the file and read the detected format, triangle count and bounds.
2
If the file is empty or unreadable, go back to the CAD export instead of fighting the slicer.
3
If the geometry is present but open, close holes and remove non-manifold edges before slicing.
4
If only the scale is wrong, correct the units in the export settings and re-export.

Questions

References

https://www.prusa3d.com/page/prusaslicer_424/
https://help.prusa3d.com/
PrusaSlicer product page
Prusa Knowledge Base slicer documentation
STL binary header and triangle-count convention

Specs verified: 2026-11-01

Each page checks the file header, triangle count, bounds and topology in this tab. No account, upload or slicer integration.

Other slicer checks

Cura

Check an STL, OBJ, PLY, 3MF, GLB or glTF for corrupt headers, empty geometry, open boundaries, non-manifold edges and unit mix-ups before you blame Cura. The model stays in this tab.

Open diagnostic

Bambu Studio

Diagnose an STL or 3MF that Bambu Studio will not open: header damage, empty geometry, open boundaries, non-manifold edges and scale errors. Local analysis, no upload.

Open diagnostic

OrcaSlicer

If OrcaSlicer fails to load a model, check the file signature, empty geometry, open boundaries, non-manifold edges and scale before trying another download. Local diagnosis, no upload.

Open diagnostic