Apply a deformer to a subdivision surface
 
 
 

When you apply a deformer to a subdivision surface selected as an object, the deformer applies to the base (level 0) vertices. To apply the deformer to a different level, select the vertices at that level and then apply the deformer. You can assign blend shapes to vertices at any level.

Creating blend shape and cluster deformers for subdivision surfaces

To create a blend shape for subdivision surfaces, you can either select the object or select vertices on a given level. If you select the object, Maya blends all vertices at all levels of the surface. If you select vertices of a specific level, Maya blends only those vertices.

To create a cluster for subdivision surfaces, you need an extra row of vertices completely surrounding the vertices you want in the cluster. These extra vertices should not be in the cluster itself, but they must exist on the surface. Without the extra row, you will experience problems weighting the vertices in the cluster.

If the extra row does not exist, select the vertices and select Subdiv Surfaces > Expand Selected Components.