What we tested
| File | UltiMaker Cura said | Actual problem | Result |
|---|---|---|---|
| 40 × 20 × 12 mm block with a 0.5 mm speck 300 mm away | Unable to slice: Please review settings and check if your models: … | 2 shells, 300.5 mm wide | Not sliced |
What is going on
Cura leaves models that stick out of the build volume out of the slice (source); if nothing is left, it shows this message (source). Such models are drawn striped on the plate. Other "Unable to slice" messages name a setting, the material, the prime tower or a disabled extruder instead.
A model that is too big is the plain case. A stray piece is harder to spot: the object list showed 300.5 × 20.0 × 12.0 mm for a 40 mm block, and the speck itself was barely visible. FixSTL reported the file as a clean solid with 2 shells and the same 300.5 mm width; it does not delete shells.
What was actually wrong
How to fix it
- Look for striped models on the plate; they are outside the build volume.
- Check the size under the object list. If it is far larger than the part, zoom out and look for a stray piece.
- Check the file in FixSTL: an extra shell and an unexpected size point to leftover geometry. Delete it in your modelling program and export again.
- If the part is simply too big, scale it down or split it.
- If every model is set as a modifier mesh in Per Model Settings, set one back to a normal model.
Source: Seen in our tests · UltiMaker Cura 5.13.0 on macOS