A named dimension style is a group of dimension settings that determine the appearance of the dimension. Using named dimension styles, you can establish and enforce drafting standards for drawings. The illustration shows types of arrowheads.
All dimensions are created using the current dimension style. If you do not define or apply a dimension style before creating dimensions, AutoCAD LT applies the default dimension style, STANDARD.
To set up a parent dimension style, you begin by naming and saving a dimension style. The new dimension style is based on the current dimension style and will include all subsequent changes to the layout of the parts of the dimension (DDIM Geometry dialog box), the positioning of dimension text (DDIM Format dialog box), and the appearance of annotation (DDIM Annotation dialog box). Annotation in this case means labels for primary and alternate units, tolerances, and text.
With dimension style families, you can design a dimension style and then specify variations on it for each dimension type without having to set up and use an entirely new dimension style.
For example, you may want to force use of a dimension line for radius and diameter dimensions only. Instead of creating a different dimension style for each dimension type, you create the parent style with Force Line Inside (DIMTOFL) turned off, and then create radius and diameter family members with Force Line Inside on. When dimensioning, you select the parent dimension style, and AutoCAD LT automatically applies the appropriate family member dimension style based on the type of dimension you're creating. In this case, AutoCAD LT forces a dimension line only when you create radius or diameter dimensions.
You can set up family member styles for linear, angular, radius, diameter, and ordinate dimensions and for leaders. Changes to a parent dimension style after it has been created and saved are not applied to family members.