ZBrush Character Creation - Advanced Digital Sculpting 2nd Edition

70 chapter 2 ■ Sculpting in ZBrush

1. Hold down Ctrl to make a mark with the
   Masking brush on the neck to represent the start
   and end of the sternomastoid muscles. The ster-
   nomastoid originates at the pit of the neck, and
   its insertion point is behind the ear at the mas-
   toid process. By making a mark for the insertion
   and origin, we can easily draw the direction and
   fl ow of the muscle as it turns around the cylin-
   der shape of the neck. When the shape is masked
   in, Ctrl-click the background to invert the mask
   (Figure 2.83).


2. Using the Claytubes brush, mass in the muscle
   form. Try to keep it thicker at the top than the
   bottom. When it reaches the pit of the neck, the
   sternomastoid splits into two distinct heads.


3. Using the Claytubes brush, sketch in the sweep
   of the clavicles (Figure 2.84).


4. Using the Rake, stroke across the forms we have just created. The intention here is to
   start to tie the shapes together with the neck. Notice the use of ZAdd rakes in the recess
   on either side of the sternomastoid. This softens the transition between the muscle and
   the rest of the neck (Figure 2.85).

Figure 2.83 Adding the sternomastoid muscle

Muscle Origins and Insertions

Many anatomy books will refer to a muscle’s point of origin and insertion. The origin of a muscle

can be determined by the direction in which it pulls or the end at which the muscle has the least

range of motion. For example, the origin of the sternomastoid is the pit of the neck; the muscle

moves the least here. The insertion is at the mastoid process. Here the muscle moves with the

head in all directions. You can also remember this by the fact that the muscle pulls down toward

the pit of the neck when in fl exion.

Figure 2.82 The sternomastoids and clavicles