The position of the text along the dimension line in relation to the extension lines is referred to as horizontal justification. To place text yourself when you create a dimension, use the User Defined option. Use the Horizontal Justification options to automatically place text at the center of the dimension line, at either extension line, or over either extension line. The vertical justification settings determine where the text appears in relation to the dimension line.
When text is at either extension line, it can be either vertical or horizontal. When it is over an extension line, it is always aligned with the extension line. The illustration shows the difference between the Centered and Above vertical justification options when text is placed above the first extension line.
First and second extension lines are defined by the order in which you specified the extension line origins when you created the dimension. For angular dimensions, the second extension line is counterclockwise from the first. In the following illustrations, 1 is the first extension line origin and 2 the second.
With the User Defined option, you can place the dimension text anywhere along the dimension line, inside or outside the extension lines, as you create the dimension. This option provides flexibility and is especially useful when space is limited. However, the Horizontal Justification options provide better accuracy and consistency between dimensions.
See Also
Justifying Dimension Text Vertically