You can modify all of properties of the existing dimension objects in a drawing using dimension styles. You can also create a dimension style override to temporarily change a dimensioning system variable without changing the current dimension style.
As you create dimensions, the system applies the default current dimension style to the dimensions. The created dimension remains this style unless you apply a new dimension style to it or set up dimension style overrides.
You can also modify the current dimension style and apply it to existing dimensions. If a dimension style is changed, the dimension associated with that dimension style updates automatically.
Override a Dimension Style
Overriding a dimension style changes a dimensioning system variable without changing the current dimension. You can define dimension style overrides for the following situations:
For individual dimensions, you may want to modify some properties of dimensions, such as suppressing a dimension's extension lines or modifying text and arrowhead placement so that they do not overlap drawing geometry, without creating a new dimension style.
Set up overrides to the current dimension style. As you have create a dimension style override, all dimensions that are created in this dimension style include the overrides, until you delete overrides, save the overrides to a new style, or make another style current. For example, you can change the extension lines' color on the Lines and Arrows tab by clicking the Override button in the Dimension Style Manager, and keep the current dimension style unchanged. However, the new value for color is stored in the system variable DIMCLRE. The extension lines of the dimension you create will apply the new color. The dimension style overrides can be saved as the current dimension style.
Dimension style includes some common dimension characteristics that are suited to be saved permanently, and some are applied on an individual basis that can be applied more effectively as overrides. For example, a single type of arrowhead is often used in a drawing, so it is suited to be saved as part of the dimension style. However, suppression of extension lines often applies in individual cases only and is more suited to a dimension style override.
The overrides apply to the dimension you are creating and all subsequent dimensions that are created with it, until you reverse it or set another dimension style to current.
DIMOVERRIDE: Overrides dimensioning system variables
DIMSTYLE: Creates and modifies dimension styles
PROPERTIES: Controls properties of existing objects
System Variables Reference
DIMCLRD: Assigns colors to dimension lines, arrowheads, and dimension leader lines
DIMSTYLE: Shows the current dimension style