Mark,
Not sure if there's a way but here's a workaround:
1) Create a dimension that's parallel to the line (not quit 3D)
2) Create the desire dimensions using the orthographic views
3) Switch dim to show the dimension id in step 2 (i.e., &ad28)
4) Edit the dimension in step 1 and use the @O &ad28 to override the dimension shown.
If your model changes so will this dimension. If there's another method, please share 🙂
Good luck!
Calvin
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