What we tested
| File | PrusaSlicer said | Actual problem | Result |
|---|---|---|---|
| Square pyramid 20 mm across, 15 mm tall, standing on its tip | There is an object with no extrusions in the first layer. | Clean solid; touches the bed at a point | Not sliced |
| Same pyramid, supports on | There is an object with no extrusions in the first layer. | Clean solid; touches the bed at a point | Not sliced |
| Square pyramid 4 mm across on its tip | There is an object with no extrusions in the first layer. | Clean solid; touches the bed at a point | Not sliced |
| Same 4 mm pyramid with its bottom 2 mm cut off | Detected print stability issues: … Low bed adhesion … | Clean solid on a 0.53 mm square base | Sliced |
| 20 mm block exported 2 mm above a 0.05 mm-wide leftover sliver | There is an object with no extrusions in the first layer. | 2 shells: the block and the sliver | Not sliced |
| Same block and sliver, supports on | No warning | 2 shells: the block and the sliver | Sliced; the block prints on supports |
What is going on
The full message adds "Object name:" and the file name (source). PrusaSlicer also warned "Low bed adhesion" for the parts standing on a tip.
Supports fixed the block on the sliver, because they can start on the bed under the block. They did not fix the tips, which still touch the bed with almost nothing.
Bambu Studio and OrcaSlicer have the same check with their own wording. FixSTL showed the pyramids as clean solids and the sliver as a second shell; it does not move or delete either.
What was actually wrong
How to fix it
- Look at what touches the bed in the preview: a point, an edge or a separate piece.
- Cut the bottom flat or rotate the part onto a flat face.
- Delete a stray piece under the part in your modelling program, or turn on supports so the part prints on them.
- Check the file in FixSTL: a small extra shell under the part is the stray piece.
Source: Seen in our tests · PrusaSlicer 2.9.6 on macOS