Ideally, a mesh will contain faces that consist of only four vertices (these faces are generally referred to as quads) and are fairly even sized. Such a configuration is optimal when deforming the mesh, as is often necessary with animations. Of course, there is nothing intrinsically wrong with three-sided faces (tris) but in general it is better to avoid them because small triangular faces wreck havoc with subsurface modifiers, causing them to show unsightly ripples.

Now even when you have a mesh that consists only of quads, some vertices are the center of more than four edges. These vertices are sometimes called poles, hence the name of the scripts in the following sections. If the number of edges is excessive, say six or more (as shown in the previous screenshot), such an area might become difficult to deform and difficult to manipulate for the modeler. In a large and complex mesh these vertices might be difficult to pinpoint and therefore we need a selection tool that selects those vertices.