At the top of the panel is a preview of the Brush alpha shape followed by a series of behavior controls.
Brush Rotation: This sets the initial orientation of the alpha at the beginning of the stroke.
Zero Pressure Radius: When using a tablet stylus, this number indicates the default radius at the beginning of the brush stroke.
Depth Modulator: The default depth for each brush being used.
Rotation Amplitude: Sets the amplitude for additional brush rotation.
Radius Variation: Sets the percentage of random brush radius variation.
Depth Variation: Sets the percentage of random brush depth.
Jitter Opacity: Defines the randomness of the brush opacity setting.
Jitter Position: The overall randomness of brush behavior.
Jitter Hue: Defines the randomness of the brush hue when used for painting color.
Jitter Brightness: Varies the brightness randomly over the course of a stroke.
Jitter Saturation: Varies the saturation of the primary color randomly over the course of the stroke.
Vary color per stroke: Use this option to produce painting effects, like fur or hair, when you need to either vary the Hue/Saturation/Brightness as you paint a single stroke (variegated strand color), or when you want each stroke made to have a slightly different Hue/Saturation/Brightness, as determined by the corresponding “Jitter” setting.
Random flip (x, y): This randomly flips the selected brush across its x or y axis while painting.
Paint with dabs: Creates paint or sculpting “dabs” which occur at some set spacing, as determined by the “Spacing” control.
Rotate along stroke: When using brush alpha shapes, you want to align like the bristles of a brush so that they change relative direction as the brush changes direction; all along the stroke, use this option.
Skip eraser: Disables the “Erase Layer” of the Brush.
Sharp Shape (old style): This check box allows you to draw alphas more sharply (it is closer to old-style 3DCoat painting). Spots will not blend with each other. It means better following alpha shape but also sharper stroke self-intersection. This option is not working for airbrush and native (not surface) voxel tools. Airbrush and voxel tools are always working in sharp mode.
Sharp Shape with all alphas: Use this setting to cause both sculpting and painting brushes to strictly adhere to the shape defined by the Brush Alpha.
Fade on edge: All strokes painted with this option checked will have a smoother edge transition.
Use spacing: When used with the “Paint with dabs” option, adjusting the “Spacing” percentage slider determines how close or far apart the paint dabs are applied.
How to fast rotate your alpha ?
Evil_Weasel: you can assign a shortcut for rotating alpha. There is an action called “Start brush rotation” in Customize navigation menu.