by John Flanagan
Introduction
Do you ever wonder why some dimensions update when the geometry changes and others do not? Dimensions that update are linked or associated with the geometry they measure (dimension associativity). Dimensions can be associative or non-associative depending on how they are created. They can also become disassociated if the geometry they measure gets deleted or exploded.
Control Whether New Dimensions are Associative
By default, all new dimensions are associative.
In the Options dialogue box, User Preferences tab, under Associative Dimensioning, make sure that Make New Dimensions Associative box is checked.
Example of an Associated Dimension
Create a new drawing and add three circles and a dimension string as shown below.
Select the middle circle and move it to the left. Observe how the dimension values change. That is because the dimensions are associated to the centres of the three circles.
Next erase the middle circle. A yellow badge displays on the dimensions indicating that they are no longer associated to the circles. Deleting the middle circle created two disassociated dimensions
Working with Disassociated Dimension
Due to the previous design change, we now have two disassociated dimensions. To fix this, we will delete the dimension that is no longer needed and reassociate the other dimension to the remaining circles.
Left click the yellow badge and choose Delete from the menu to remove the dimension that is no longer required.
Left click the yellow badge on the remaining dimension and choose Reassociate from the menu. Use object snaps to accurately select the centre of the circles to reassociate the dimension to the remaining circles.
The yellow exclamation badge disappears, indicating that the dimension is now associated with the centres of the two remaining circles.
Move the circle to the right. The dimension displays the new distance between the circles.
Note: When the annotation monitor is off, there is no visual indicator that displays if a dimension is associative or non-associative.
To Turn the Annotation Monitor On
Click Customisation, located at the far-right end of the status bar, and select Annotation Monitor. When the annotation monitor is active, the Annotation Monitor icon is added to the status bar.