82 chapter 3 ■ Designing a Character Bust
If you have holes in your base mesh that you want to maintain—for instance, a head that
is separated from a shirt—you will find smoothing in ZBrush will cause the border edges
to shrink. To correct this when you import your base mesh, click the Geometry Crease
button under the Tool menu. This will tag the border edge of the geometry and keep it in
place while smoothing the rest of the model.Other options for generating meshes directly inside ZBrush include the tools ZSpheres
and ZSketch. ZSpheres allow you to create organized polygon meshes quickly by drawing
interconnected chains that are converted to polygon meshes. Although ZSpheres do not offer
the same control of edge placement that direct polygon modeling does, ZSpheres use certain
controls to create form and edge loops. The resulting models are light, organized, and ready
for subdividing and sculpting.
ZSketch, on the other hand, allows you to create models by building up volumes with
successive brush strokes. The meshes generated from ZSketch are denser than ZSphere meshes
and usually require different working methods. Figure 3.5 shows examples of both ZSphere and
ZSketch meshes.Optimizing Meshes for ZBrush
In this section we will import a simple mesh to show how a poorly distributed edge layout
can create problems with sculpting. For this example I’ll use the model goblin in Figure 3.6.
Notice the edge distribution on this character. The goblin has a concentration on edges in the
face and arms. These areas will subdivide denser than the rest of the body as you subdivide—
which may be desirable in some cases, but most of the time it’s best to keep an even mesh.
Preplanning is key to getting a suitable mesh into ZBrush. If you can avoid topology at the
outset and remesh later, I find that is the most versatile approach.
Also notice the stretched faces in his tail (Figure 3.7). Because the faces are tighter in the
body and longer in the tail when subdividing, they will not divide as densely as other areas,
making details in the tail softer and less sharp.Figure 3.5 A ZSphere model on the left and a ZSketch model on the right