UVs in ZBrush
UVs are the coordinates that allow the computer to unwrap a 3D object into a 2D plane for texture application. A good analogy is to think of unstitching a soccer ball and laying it out flat (Figure 5-1); this is a spherical object that has been unfolded into a flat plane. In Figure 5-2 you can see a 3D model of a head and the accompanying UV Texture coordinates. There are several methods of generating UVs using ZBrush’s built-in automatic mapping tools, or you can lay out UVs by hand in third-party applications such as Maya or Headus UV.