Model-Based Definition > Model-Based Definition > Annotation Features > Annotation Feature Basics > Strong and Weak References
Strong and Weak References
The Annotation Element references can be Strong or Weak:
Strong references are checked during regeneration of the Annotation feature. If a Strong reference is lost, the Annotation feature fails regeneration.
Weak references are checked at the end of the model regeneration. If a Weak reference is lost, the Annotation feature does not fail regeneration. If the missing Weak reference is used by an annotation leader, the leader is lost (not displayed). If the last remaining leader is lost, the annotation becomes inactive. Inactive annotation is not displayed.
For example, if an Annotation Element includes a note, and the note is attached to two edges, then the two edges are Weak references. If one of the edges is not found at the end of regeneration (for example, if was chamfered somewhere later in the regeneration sequence), the leader that used to be attached to this edge is not displayed. The note has only one leader, attached to the second edge. However, if the second edge is also lost, the note would lose its last remaining leader and become inactive.
When the references are automatically populated from an annotation item, they are designated Strong or Weak according to the following rules:
Annotation plane is a Strong reference.
Leader attachments are Weak references.
The reference entity of a Geometric tolerance (the entity to which the GTOL applies) is a Strong reference.
In Driven and Reference dimensions, all their references are Strong, because without these references, the dimension cannot exist.
By default, all the additional Annotation Element references that you select are Weak. You can change a reference to Strong by selecting the checkbox in the Strong column next to the reference name in the appropriate reference collector in the ANNOTATION FEATURE dialog box.