A deformer can create deformation effects on any deformable object. NURBS curves, NURBS surfaces, polygonal surfaces (meshes), and lattices are all deformable objects.
A character’s model can consist of one deformable object (for example, a large polygonal surface) or groups of deformable objects (for example, groups of NURBS surfaces).
Control points
A deformable object is any object whose structure is defined by control points. Control points include NURBS control vertices (CVs), polygonal vertices, and lattice points. In this documentation, control points are often called points, and the control points of deformable objects are often called deformable object points.
Maya automatically converts edges and faces into vertices when you create a deformer that supports polygonal components. For example, select an edge loop, then select Create Deformers > Cluster to add a cluster to the selected edges.
Deformer sets
When you create a deformer, Maya puts all the deformable object points that the deformer can affect into a set, called a deformer set. This set is editable. For more information, see Editing deformer set membership.