Design Nomenclature / Form & Geometry
Pole
Also called star, singularity, extraordinary vertex, e-pole, n-pole
This entry has not been translated yet and is shown in English.
A vertex where a number of edges other than four meet — three-valence (E-pole) and five-valence (N-pole) being the common cases. Poles terminate edge loops and concentrate Gaussian curvature, so under subdivision a small region around them cannot be made smooth. A closed quad mesh cannot be built without them.
In practice
'Star' or 'singularity' in CAD. The craft is not eliminating poles — on a sphere the valence defects must sum to exactly eight, so it is impossible — but parking them in flat, low-curvature regions that never deform.