In the next steps, you create a cluster deformer on the duplicated face (target object) to reshape the expression into a smile. The cluster deformer on the target object will be used to change the unsmiling baseFace (base object) into a smiling face.

A cluster deformer creates a set whose members consist of selected points (CVs, vertices, or lattice points). You assign a percentage weight to each point, indicating how much you want each point to be affected by any translation, rotation, or scale of the cluster set. When you transform the cluster, the points are transformed according to the percentages you have specified. A cluster is useful for stretching, moving, or compressing part or all of a surface.

To create a cluster deformer

1. Position the mouse pointer over the face, then right-click and select Vertex from the marking menu.

   Next, you’ll select the smilingFace vertices as shown in the illustration, which are roughly the vertices at the chin, cheeks, and lips, but not the nose.

   

2. An easy way to select the vertices is to use the Paint Selection Tool. Open the Paint Selection Tool by double-clicking the icon in the Toolbox to display the Paint Selection Tool settings.

   

3. In the settings window, set Radius(U) to 0.2. Drag the mouse over the desired vertices to select them. Ctrl-drag (Windows and Linux) or Control-drag (Mac OS X) to cancel the selection of unwanted vertices.

   The region of selected vertices does not need to be exact, although you want to avoid selecting vertices at the back of the head inadvertently. Also make sure you don’t inadvertently miss a few vertices in the region you do want to select.

   The objective is to select all vertices where a smile might deform the face. You might want to look in a mirror to see which parts of a face move while smiling. It’s better to select too many vertices than too few. It’s easier to work with too many vertices than too few.

4. Close the Tool Settings window when you are finished.
5. Select Create Deformers > Cluster.

   This puts the vertices into a cluster—a set of points you can move as single entity. The cluster’s handle appears in the view as a C icon.

6. In the Outliner, make sure the cluster2Handle is selected.
7. Use the Move tool to drag the cluster handle up along its Y-axis a small amount until smilingFace is deformed as follows:

   

   The cluster set on smilingFace should be slightly higher than the cluster on the original face. This will become the basis for the blend shape deformer.