You can remove a raster arc by picking the start, center, and end points of the raster arc. You must set an appropriate line width. For more information, see Rub and Crop Line Width.
Note: Unlike previous versions of AutoCAD Raster Design toolset, rubs permanently change the raster data after you have saved the image. They do not temporarily remove raster data from the display. To reverse a rub, use the AutoCAD UNDO command.