Reply To: Purpose of the star junctions

Another way of looking at this:

a head as we sculpted is topologically equivalent (homeomorph) to a sphere (if you did it well and didn’t make holes in the mesh) and you cannot retopologize it without poles. (I can prove this, but it is not trival) The only 2 dimensional object in 3D space that can be made without poles is a (one-holed) torus (or something homeomorph to it, like, for instance a coffeecup (with handle)).

Now we want to subdivide it later to sculpt fine details, so we want a retopology that has (almost) only quads and they should be as similar in size and ‘squareness’ as possible and as we have non-concentric loops (around the eyes and mouth for instance), we need star junctions between them to avoid stretching like this:

The placement of those poles on an organic model takes into consideration, where they can do the least harm when the mesh deforms.