In this section you will use the Paint Cluster Weights Tool to further refine the smilingFace. As you saw in previous steps, the points in a cluster move when you move the cluster handle. The distance a particular point moves depends on its weight. Lower weights cause less movement, while higher weights cause exaggerated movement. In the next steps, you create a smile by editing the weights.

To edit cluster weights using the Paint Cluster Weights Tool

1. Select smilingFace.
2. Select Edit Deformers > Paint Cluster Weights Tool > . This displays the smilingFace in grayscale.

   

   The white area shows the points that make up the cluster. The whiteness also indicates the weights—how much the points move in response to the movement of the cluster handle. White indicates a cluster weight of 1—the points move the same distance as the handle. By default, each point has a weight of 1.

   Black indicates a cluster weight of 0. The points do not move in response to cluster handle movement. Note that regions that are not part of the cluster are also black.

   Although there are no gray regions currently, gray means the movement is partial. The lighter the gray, the more the movement. Gray regions indicate a cluster weight between 0 and 1.

3. In the Paint Attributes section of the Tool Settings window, set the following:
   • Paint Operation: Replace
   • Value: 0.5
4. Click Flood.

   This gives all the cluster points a weight of 0.5. The white region is now gray:

   

   The selected vertices move down a bit, as the weight of 0.5 lessens the effect of the prior movement of the cluster by 50%.

5. To check the shape with full-color shading, click the Select Tool. (You might also prefer to cancel the selection of smilingFace to eliminate the display of the highlighted wireframe.)
6. To return to the Paint Cluster Weights Tool, select smilingFace and Edit Deformers > Paint Cluster Weights Tool > again.
7. In the Tool Settings window, set the following:
   • Radius(U): 0.1

     A Radius(U) of 0.1 sets the radius of the region affected by the stroke. The red circle icon on the face displays the radius.

   • Opacity: 0.3

     An Opacity of 0.3 scales down the effect of painting weight values so you can build up values gradually with repeated strokes.

   • Paint Operation: Replace

     A Replace operation paints the Value specified on the points stroked.

   • Value: 1

     A Value of 1 sets the weight value you paint on the points.

8. Paint the region at the corners of the mouth with repeated strokes until the face looks roughly like the following figure. If your results differ from the figure significantly, undo the strokes and try again.

   

   While painting weights, it’s useful to intermittently check the shape with with full-color shading rather than with the grayscale shading. To do this, click the Select Tool to turn off the Paint Cluster Weights Tool. (You might also prefer to cancel the selection of smilingFace to eliminate the display of the highlighted wireframe.)

9. Enter a Value of 0.25 and paint the central region above and below the lips as follows:

   

   Because the corners of the mouth have a high weight and the central region around the lips have a low weight, the corners move up more in response to the prior positioning of the cluster handle. This creates a smiling mouth. The cheeks and chin have a medium weight, so they also move up slightly also. (For many people, skin at the chin and neck moves during smiling.)

10. In the tool settings editor for the Paint Cluster Weights Tool, set the Paint Operation to Smooth. Paint any region where the surface has become irregular. Irregular regions are typically indicated by jagged wireframe curves (isoparms) or where a grayscale color makes an abrupt change to a lighter or darker color. Smoothing averages the weights of the stroked points with the weights of the surrounding region. The Value setting has no effect on smoothing.
11. Replace and smooth weights in other regions of the face until you are satisfied with the smile. For example, you might want to reduce the weight values at the side of the nose and immediately below the nose.

    Your smilingFace should now have a slight smile as a result of your cluster weight edits.

12. Hide the Paint Attributes Tool settings window.