The size and scale at which annotation objects are displayed in model space or a layout are controlled by annotative objects and styles. The process of scaling annotation objects is automated when you use annotative objects.
The difference between a normal dimension and an annotated dimension is that the latter is intelligent and always appears in the same size regardless of the view scale.
The annotative property was introduced in AutoCAD 2008 and is a valuable tool for maintaining the size of annotations in AutoCAD. Prior to the introduction of AutoCAD's annotation scale, plotting objects with the correct scale for different viewports was a time-consuming effort.
Text or a dimension can be added.
Change the Annotative setting in the Properties palette to Yes.
To enter the Annotative Object Scale dialogue, click the "..." next to the current scale.
After you've added all of the necessary scales, click OK.
Choose a viewport. Choose Properties from the context menu when you right-click on the drawing area. Select the Annotative Scale property in the Properties window and set the current scale.