This setting specifies the line width to use with the Rub and Crop commands: Circle, Line, Polyline, Arc, and Crop Line.
This value is also used if you have Rub selected as your VTools Removal Method. As you trace your raster objects, the vectorization tools use the rub/crop line width to determine the width of the raster that is rubbed. For more information, see General VTool Settings.
Changes that you make to Autorub at the command line update the settings in the Raster Design Options dialog box: