| 15 | | * Remove double vertices, edges and faces. |
| 16 | | * Vertices in plain air |
| 17 | | * Faces, edges and vertices inside your mesh |
| 18 | | * Overlapping faces |
| | 15 | * Double vertices, edges and faces. In Edit Mode, you can remove double vertices by selecting all and hitting W -> Remove doubles. |
| | 16 | * Non-manifold edges, that means edges that do not have exactly 2 adjacent faces. To see which edges are non-manifold, switch to edge selection mode in Edit Mode and choose Select -> Non-manifold. |
| | 17 | * Vertices in plain air. |
