To Draw Center Marks and/or Centerlines for Radius and Diameter Dimensions (AutoCAD Mechanical Toolset)

In the drawing area, double-click the radial or diameter dimension you want to edit. The Power Dimensioning Ribbon Contextual Tab displays.
Click Power Dimensioning tabFormat panelEdit Geometry.
In the graphic showing the dimension, select the center marks. Click once for a center mark. Click twice for a centerline.
Under Center mark size, enter the desired numerical value.
Click OK.
Note:
If arrows or text are inside the arc, center marks do not appear as part of a dimension.
Click Power Dimensioning tabClose panel Close Editor. Find