3ds Max Modifiers - Affect Region
The Affect Region modifier is a surface modeling tool, primarily used with vertex sub-object selections while surface modeling. With Affect Region, transforming a selection of vertices can also transform vertices in the region that surrounds the selection. This can help you form a bubble or indentation in the surface of an object. The easiest way to see this modifier's effect is with a shallow, flat box object with plenty of subdivisions. The Affect Region modifier has a two-part, arrow-shaped gizmo plus numeric controls.
My 2 Cents : I hardly ever use this modifier, but as a way to keep a parametric selection it seems like it would be useful. Paired with other modifiers like Slice or Noise, I think one could get interesting results. In the past (prior to looking into this modifier) I would apply an Edit Poly modifier, use soft selection and leave the selection active. Essentially, it is a parametric soft selection.
