I'm completely new to 3D Modeling. I don't have a favorite modeler yet, but maybe a few questions will get me moving in the right direction?

The first thing I want to do with any modeler is import a Head MT.OBJ. I see the next thing I'd be doing as pulling on vertexes, but I know one of two things are going to happen. A.) It will be the only thing that moves, thus causing a sharp spike in the surface of my MT, or B.) There will be a standing rule in place which dictates how many of the surrounding vertexes move with it, and how, in order to keep the skin looking smooth always.

What is this rule known as? Are there any Modelers that have a particularly large selection of variations of this rule?

= )