About Annotation Orientation by Plane
You can define the orientation for annotations by selecting a datum plane or flat surface which is parallel to the annotation. The annotation orientation defined by a reference plane can be driven by plane or frozen. You can place an annotation on the reference plane if its annotation orientation is defined by plane.
Driven By Plane
When an annotation orientation is driven by plane, the datum plane or flat surface is displayed as a reference of the Annotation Element in the References collector in the ANNOTATION FEATURE dialog box. If you delete the reference, Creo Parametric replaces the reference with an alternative reference. If an alternative reference is not found, then the orientation becomes frozen. Similarly, in a model annotation if the reference is deleted, then the annotation is not displayed.
If you change the datum plane or flat surface orientation, the annotation orientation changes accordingly.
When an annotation orientation is frozen, the annotation orientation is stored in the annotation and the annotation plane reference is not required. Therefore, even if you delete the plane reference, the annotation is not affected.
Creo Parametric does not display references for an Annotation Element with a frozen annotation orientation in the References collector in the ANNOTATION FEATURE dialog box
You can switch the annotation orientation between the driven-by-plane state and frozen state by clicking or clearing the Freeze annotation plane reference check box. However, you can revert the annotation orientation of an annotation to the driven-by-plane state only if the annotation plane still exists.
It is not necessary to place or copy the datum plane of an annotation with frozen annotation orientation to UDF or DSF. You can change the annotation orientation of the target Annotation Element independent of the source Annotation Element.