Reply To: Questions regarding the “Pull” or “pinch”?

Hi Nougat,

The whole issue of Poles, has to do with the effect of unevenly sized Faces on the shading of a Mesh and on its deformations.

If you have two Edges close next to each other, the Subdividing the Mesh, will give a high density of Edges in that area. (I think that one is obvious. Look at your last screenshot, for instance).

With Poles, sort of the opposite happens. To understand this, you need to know, that the Subdivision Surface algorithms use the center of Faces and connect them to the (center of the) Faces’ Edges.

The more Edges are connected to a Pole, the smaller the angle between two adjacent Edges, and the center of the Face gets ‘pushed’ away from the pole, so the density of the Mesh around a Pole, when Subdividing is less, than further away from the Pole:

See how the centers get ‘squeezed’ outward, away from the Pole. This, together with the fact that the ‘pizza slices’ also get more ‘stretched’, when the number of connected Edges of a Pole increases, can cause serious Shading issues and uneven deformations.

If there are not going to be any deformations, Poles and N-Gons are usually no problem if they are on flat surfaces.

I hope this helps a bit.