Center marks and centerlines Center marks and centerlines are dimensioning references to centers of holes and axes of symmetry. Center marks and centerlines are associative objects. If you move or modify the associated objects, the center marks and centerlines adjust accordingly. You can disassociate center marks and centerlines from objects, or reassociate them to selected objects. Center Marks You can create a center mark to indicate the center of a circle or an arc. You can control the center mark size and the scale and font of the centerline extensions. You can also turn off the centerline extension. Centerlines You can create an associative centerline by selecting two line segments. A centerline is created between the apparent midpoint of the start and endpoints of the selected two lines. When selecting nonparallel lines, the centerline is drawn between the imaginary intersection point and the endpoints of the selected lines. The centerline bisects the angles of the two intersecting lines. In this example, the location of the pick points defines the direction of the centerline. Limitations The center mark and centerline feature set is available as an alternative to current methods. This feature set is best suited for the following: Drawings that will be printed or published from model space. Drawings that are annotated in paper space. Both annotative scaling and dimension style support is not available.