Masks began as a way of protecting surfaces so that they would be unaffected by your subsequent sculpting and painting. Over the ten year history of ZBrush they have evolved to accommodate a wide variety of needs. Masks continue to protect surfaces, giving greater control as you work. They can also be used to define parts of your model that you wish to extract into a whole new object. They are at the heart of Shadow Box – ZBrush’s powerful silhouette-based mesh generation tool. There’s no limit to what you can accomplish with masks!
Because masks are so important to sculpting and painting in ZBrush, we have greatly enhanced the ways that they can be drawn. A single keyboard and mouse combination can instantly mask the entire visible surface of the model. They can be derived from an alpha that has been applied to the model or from a texture’s intensity, saturation, etc. Masks can also be generated on parametric objects by capitalizing on their mathematically precise shapes to mask rows and columns of polygons. Most powerful of all, however, is the fact that ZBrush 4 fundamentally changed the way that masks can be painted on your model by converting the feature into an actual brush.
In fact, there are five masking brushes: Mask Circle, Mask Curve, Mask Lasso, Mask Pen and Mask Rectangle. Each of these offers specialized and highly useful ways to paint masks onto your figures. And because these are brushes they are also able to take advantage of all the same brush modifiers that you use for sculpting.
The more you use masks, the more you will wonder how you ever lived without them!