The Backup Refs checkbox next to the Annotation Element name defines whether the backup references of the Annotation Element are to be created within the Annotation Element.

Creating the backup references of an Annotation Element ensures that the reference does not change during regeneration of consecutive features.

In the following example, an Annotation Element of type Note is created and attached to a middle point of the front surface of the part.

Later, a cut is created. The cut trims the front surface. If the Annotation Element was created without the backup references, the note attachment is recalculated and updated to reference the middle point of the new surface.

If, at the time of creating or redefining the Annotation Element, the Backup Refs checkbox is selected, the system creates an invisible backup surface, and both the Annotation Element and the note reference this backup surface instead of the new surface. In this case, the note attachment is not displaced.