You can create intersection lines for dimensions created in the drawing. Unfortunately you cannot do it for dimensions created in the model and then shown on the drawing.
For Creo 4.0:
- select dimension
- click "display" button
- select "enable intersection witness lines" checkbox
For Creo 2.0:
- select dimension
- right click and select "properties"
- select "display" tab
- select "enable intersection witness lines" checkbox
