Lock angled model lines with out using align

[jwilliams16644965]

I am trying to make a simple nominal lumber section detail family that can adjust in length in the model.
I have looked at similar families and have noticed that they have been able to lock model lines and angled lines that are not directly aligned with a reference line. I know how to create and set the parameters for a simple 2D box drawing but when I put in the two crossing lines indicating a cut through the lumber it will not allow me to expand the blocking. Attached is an example of what I would like the family to do. Any feed back would be appreciated.

[DaveP]

Detail Lines like that are kind of one of Revit's magic things.
There's nothing you really DO to make them lock, they just do.
The thing I've found most reliable is to be specific when you draw the diagonal lines and explicitly tell Revit you want to snap the the Intersection of the other lines by typing SI before you place each endpoint. Once it's drawn, if you go back and select the line, you should see the lock icon to verify.

[jwilliams16644965]

Thank you so much!!! It worked like a Charm!