Vertical Design Rules were designed to use coordinates independent of the lines. With the tolerance this allows the user to make minor adjustments to the lines as well as add and remove lines from the design and the rules will find the lines and update the design. Tying to a station of a line ties it to a line that might get broken, edited or otherwise changed that would break the rule. Typically only the centerline of a corridor has the desired stationing as the offset lines have different lengths and may be in segments.
The initial design is to not allow them to be moved as they depend on specific selected lines and the relative position of the rules. You can however adjust them one at a time using grips. If you select a slope rule that goes from one line to another you can pick the center grip and the rule will slide along between the two lines.
As always we are open to improving how the product works but the changes must work with the primary workflow being addressed. We welcome more discussion on these tools and how people want to use them. There are sure to be many enhancements and fixes we can do.
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