Used to drag a group of vertices around. Grab selects a group of vertices on mouse-down, and pulls them to follow the mouse. And unlike other brushes, Grab does not move different vertices as the brush is dragged across the model. The effect is like moving a group of vertices in Edit Mode with Proportional Editing enabled, except that Grab can make use of other Sculpt Mode options (like textures and symmetry).
Snaps the maximum strength of the brush to the highlighted active vertex, making it easier to manipulate low-poly models or meshes with subdivision surfaces.
Enabling this option also enables a dynamic mesh preview which generates a preview of vertices connected to the active vertex. This helps to visualize the real geometry that is being manipulating while sculpting with Modifiers.
Attempts to preserves the object's silhouette shape. The shape of the silhouette is determined by the orientation of the 3D Viewport.