The Mask By Polygroups option in the Brush > Auto Masking sub-palette can speed up sculpting and polypainting by confining your strokes to a single polygroup when working. By using the Polypaint/Material/Masking to Polygroups’ commands, you can quickly set up complex polygroups to aid your sculpting and/or polypainting. Just brush on some high-intensity colors or materials (preferably with the Layer brush for hard-edges) and then use the various Polygroup commands (see the Tool>Polygroups sub-palette) to convert the areas into polygroups. Afterwards, simply crank up Brush > Auto Masking > Mask By Polygroups to 100 to confine your strokes to the first group you click on. You can also take advantage of the GroupsLoops feature to create edge loops around your polygroups for clean painting and sculpting effects.