Select Degeneracies selects degenerate triangles: very long and thin triangles, or triangles collapsed almost to a line. Such triangles are common in tessellated CAD exports and can cause problems in later steps, for example in simulation. Use the tool to see where they are before you repair or remesh the model.
Select degenerate triangles
- Select one mesh in the scene list.
- Click Select › Select Degeneracies. The panel opens, and the degenerate triangles are selected at once.
- Change Min Aspect Ratio if needed. The selection updates as you change the value.
- Close the panel.
The found triangles are added to the selection the mesh had when you opened the tool.
Settings
| Setting | What it does | Default |
|---|---|---|
| Min Aspect Ratio | Selects triangles with an aspect ratio of at least this value. The aspect ratio is the radius of the circle through the three corners divided by twice the radius of the circle inside the triangle: 1 for an equilateral triangle, larger for longer and thinner ones. Lower the value to select more triangles. | 1000 (shown as 1.000e+03); the minimum is 1 |
| Boundary Only | Selects only degenerate triangles that have at least one boundary edge, on the edge of a hole. | Off |
The drop-down arrow next to Select Degeneracies opens Select Outer Layer, a separate tool for double-layer meshes.
Fix degenerate triangles
- Turn on the Zero-Area Triangles check of Mesh Healer. It finds triangles by the same aspect ratio (Triangles Aspect Ratio in Advanced Mode) and fixes them.
- To improve thin triangles without moving vertices, use Make Delone. To rebuild the triangulation with nearly equal edges, use Remesh.
- To remove the selected triangles, use Delete Selected, then close the gap with Fill Holes.
