[Figures 6 & 7] The shapes of the muscles of the face correspond to the surface layout used in the NURBS.
[Figures 8 & 9] The patch surface layout of the ear.
[Figures 10 & 11] The patch model has several advantages to the single-surface modeling paradigm.

The original NURBS ear is shown in Figure 8. The surface layout of the ear is similar to the surfacing layout used at the mouth and eye. Using a single surface to describe the center of the ear and having the detailed areas of the ear radiate out from the center are efficient ways to get the required detail of the ear and have this complex area transition to the smooth area of the cheek. Figure 9 shows a diagram of the surfaces.

Why a NURBS Patch Model First?
In earlier chapters, the subject of creating a model that has parameterization that follows the flow of the geometry is mentioned. Modelers can use other modeling paradigms for building a character’s face, but no method handles the issues related to building a character’s head as well as the patch modeling method. Other modeling techniques, such as the single-surface head, do not cover all of the issues related to surface layout as well as the patch modeling method.

First of all, the flow of the geometry does not match the musculature beneath the skin as well. And the single- surface head (Figure 10) has to overcompensate for the detail in the nose and eyes by adding isoparms. The patch model (Figure 11) can use less geometry and include just as much, if not more, detail. Most important, the extreme stretching that occurs at the back of the face and around the chin on the single surface head does not occur at all on the patch model.

Overall, a patch model has a more even distribution of geometry in the proper location, which makes this a great starting point for building the rest of the model.