About direction lines and direction points


    Before you draw and modify curved segments with the Pen tool, it's important to understand two elements that are associated with anchor points on curves. When you use the Direct Selection tool or Lasso tool to select an anchor point connecting curved segments, the segments display direction lines, which end in direction points. The angle and length of the direction lines determine the shape and size of the curved segments. Moving the direction points reshapes the curves. Direction lines don't print.

    For information about selecting anchor points, see Selecting path segments or anchor points.

    After selecting an anchor point (left), direction lines appear on any curved segments connected by the anchor point (right).
    After selecting an anchor point (left), direction lines appear on any curved segments connected by the anchor point (right).

    A smooth point always has two direction lines that move together as a single, straight unit. When you drag the direction point of either direction line on a smooth point, both direction lines move simultaneously, maintaining a continuous curve at that anchor point.

    In comparison, a corner point can have two, one, or no direction lines, depending on whether it joins two, one, or no curved segments, respectively. Corner point direction lines maintain the corner by using different angles. When you drag a direction point on a corner point's direction line, the other direction line, if present, does not move.

    Adjusting direction lines on a smooth point (left) and a corner point (right)
    Adjusting direction lines on a smooth point (left) and a corner point (right)

    Direction lines are always tangent to (perpendicular to the radius of) the curve at the anchor points. The angle of each direction line determines the slope of the curve, and the length of each direction line determines the height, or depth, of the curve.

    Moving and resizing direction lines changes the slopes of curves.
    Moving and resizing direction lines changes the slopes of curves.