Description

The flexibility of the surface, and hence the complexity of shape that it can model, are determined by the degrees of freedom available. This is measured in terms of the number of individual patches and the way they are distributed, plus the number of control points defining each patch.

Increasing the number of patches and/or control points enables more complex shapes to be modelled. However, this increases the danger of the surface being unfair, and also makes the surface less amenable to correction through the manual manipulation of control points.