A number of Datum Feature symbols attached to the surface edges of objects in a Board Assembly View.
A Datum Feature is a graphic object that can be placed on a Draftsman document sheet to identify a physical feature to which it is attached, such as an object edge. It acts as a reference on that drawing object so that relative dimension tolerances included in Feature Control Frames can refer to this and other placed datum.
Datum Feature objects are available for placement in the Draftsman Editor as follows:
Choose the Place»Annotations » Datum Feature command from the main menus.
Click the button in the graphic objects drop-down on the Active Bar located at the top of the design space. Click and hold an Active Bar button to access other related commands. Once a command has been used, it will become the topmost item on that section of the Active Bar.
Right-click in the drawing design space then select Place » Annotations » Datum Feature from the context menu.
Click the the entry on the Drawing Annotations toolbar (View » Toolbars » Drawing Annotations to enable).
After launching the command, the cursor will change to a cross-hair and the editor will enter Datum placement mode. Placement is made by performing the following actions:
Position the cursor over a highlighted object edge then click to attach the Datum Feature to that object face.
Move the cursor to set the position of the Datum label then click again to complete placement.
The graphical method of editing allows a placed Datum object to be selected in the design space and its edge attachment point or label location changed. When a Datum Feature object is selected, editing handles/nodes become available at its attachment and header label points.
A selected Datum Feature with its two positioning nodes
Click and drag the label node to reposition it on the drawing document.
Click and drag the edge attachment node to reposition it along the selected object face. An extension line is added when the attachment point is moved beyond the boundary of the object face.