Generally, all planes are used to flatten, reduce the thickness of, and impart a smooth surface to a rough piece of lumber or timber. Planing is also used to produce horizontal, vertical, or inclined flat surfaces on workpieces usually too large for shaping, where the integrity of the whole requires the same smooth surface. Special types of planes are designed to cut joints or decorative mouldings. A longer sole registers against a greater portion of the board's face or edge surface which leads to a more consistently flat surface or straighter edge. Conversely, using a smaller plane allows for more localized low or high spots to remain.