Create drawings from models (Creo Elements/Direct Annotation) > Modify drawings > Add and modify dimensions > Modify dimensions > Extend an external base point
  
Extend an external base point
To extend an external base point,
1. Click Annotation and then, in the Annotate group, click More.
2. Click Extend external base point.
3. Click the dimension line whose base point you wish to extend.
4. Click a new location for the dimension line starting point.
5. Click to complete the operation.
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You can only extend external base points for JIS, DIN, and ISO dimensions.