Datum Center Plane Elements on a rectangular, symmetrical part or feature can be located and dimensioned in relationship to a datum center plane. Axis and center plane datum feature symbols must align with or replace the dimension line arrowhead or be placed on the feature, leader shoulder, dimension line, or feature control frame. The representation and related meaning of datum center plane symbols are shown in Example 3-39. Datum center plane Datum center plane Datum center plane Datum center plane Datum center plane Example 3-39. Placement of center plane datum feature symbols. Chapter 3 Datums 111