About Working with Draft Datums
When you create a draft datum in parametric Sketcher mode, the draft datum and the entity that it references maintain a parametric association.
You can manually adjust the ends of the draft datum that you create on the entity, by dragging the end handle. However, you cannot manually adjust the ends of a draft datum that you create using a vertex.
If you change the draft datum to a draft set datum, the parametric association between the draft datum and the entity that it references, is not affected.
The draft datum that references a model entity is similar to a parametric draft sketch entity. That is, if you move, delete, or erase the view of the model entity that the draft datum references, then the draft datum is also moved, deleted, or erased, respectively.
Similarly, the draft datum that references a draft entity is similar to a parametric draft sketch entity. That is, if you move the draft entity that the draft datum references, then the draft datum also moves. However, if you delete the draft entity, the draft datum is not deleted.
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The draft datum created in releases prior to Pro/ENGINEER Wildfire 4.0 remain non-parametric to the entity that it references.
Use the leader_elbow_length Detail option to set the default length of the leader elbow for a draft datum and model datum. However, use the set_datum_leader_length Detail option to set the default length of the leader for a draft set datum and model set datum.
If you change the value of the set_datum_leader_length Detail option, the new default length is set for the leaders of new set datums. This will also change the leader length of all existing set datums whose leader lengths have not been previously adjusted.
If you explicitly change the length of the leader for a set datum, the value of the set_datum_leader_length Detail option no longer affects the leader length of that leader.