86 chapter 3 ■ Designing a Character Bust
Common Topology Issues
You may encounter problems when using models that contain irregular topology. ZBrush
prefers quad geometry or tris. A quad is a polygon face with only four vertices whereas a tri
has only three (Figure 3.11). ZBrush will not accept n-gons, that is, a polygon with five or
more vertices. ZBrush will triangulate these faces before importing.Figure 3.11 The polygon on the left is a quad, the middle is a tri, and the right is an n-gon.Another common problem will come in star configurations (also known as extraordi-
nary vertices). These can sometimes pinch while sculpting and be difficult to smooth out.
They will also often cause problems when rendering with a displacement map in Maya. This
will usually manifest as a pinch or split in the mesh.Increasing Polygon Counts with Local Subdivision
In some cases, you may find that you need to subdivide certain areas more than others. This
could be when you are working on a character in costume whose body is not as important
as, say, his head and hands. In these instances, it is good to keep your subdivisions in these
areas to maximize detail instead of spreading it over the entire model. Another case may be
that you have maximized your subdivisions and yet you still need more detail in a certain
area of the mesh. A full subdivision level would put you over the max levels, but dividing a
portion of the mesh would work. You can accomplish this with local subdivision.
To locally subdivide a mesh, follow these steps:- Load your ZTool into ZBrush, enter Edit mode with the T key, and step up to the highest
subdivision level.