How to spot it
- PrusaSlicerAuto-repaired 4 errors: 4 degenerate facetsPrusaSlicer 2.9.6 source
- Blender 3D Print ToolboxDegenerate: faces and edges which have 0 area or length3D Print Toolbox wiki
Why it happens
- Coordinates rounded to fewer digits on export
- Conversions between formats
In our tests
83/ 89
89 of the 198 public test files had zero-area or duplicate faces. After FixSTL’s repair, 83 were free of them.
The faces themselves almost always go; whether the whole file is repaired depends on what else is wrong with it.
Public Thingi10K test set, FixSTL engine 0.6.0 (a7ea280), default repair. How we test
How to fix it
What FixSTL does
- Removes zero-area and duplicate faces
- Welds corners that almost touch; nothing moves more than 0.1% of the model’s size
What it leaves
- Removing a sliver can leave a gap; that gap is then an open edge to fill
Elsewhere
- Blender Mesh › Clean Up › Degenerate Dissolve, then Merge by Distance