Feature Line Relationship Lock

Summary: Lock the relationship between points on a feature line.

Description: Feature Line Elevation Relationship Lock:
I would like to see, within a Civil 3D feature line, the ability to lock or hold a specific relationship between elevation points (vertices). In other words, if I have a feature line with two vertices (A & B) and a grade between A & B of 2%, I�d like the ability to change the elevation of vertex A and maintain the same grade of 2%, effectively forcing the elevation of B to increase to satisfy the specified relationship. One might say that we can �lock� the relationship between vertices A & B.

How Used: Where I see a practical application of this ability would be within sub-division lot grading. With the introduction of �dynamic feature lines from a corridor� there exists the prefect beginning for simplified lot grading, but without the ability to lock the relationship between elevation points on a feature line (as described above) a true dynamic solutions falls short.
Most (if not all) lot grading uses some elevation along the street or curb as the basis for establishing lot/pad elevations.

Feature Affinity: Feature Lines

Submitted By: Mike Bandich on May 29, 2008

Did you ever figure this out?

There is no perfect solution for this, as Civil 3D just isn't designed for residential lot grading.

If you 'lock' the Feature Line grades, then you can disrupt the OOTB relationship between Feature Lines on the same Site, or now have to make your drawings more complex to account for more Sites... But this can be done:

https://www.screencast.com/t/NJjPseV7BfAM

https://forums.autodesk.com/t5/civil...t/true#M408987

https://forums.autodesk.com/t5/civil.../idi-p/8043560

Don't forget that all lots aren't necessarily the same; we'd need a mechanism to define, assign, modify, identify & remove these different 'Feature Rules', so some simply reside themselves to grading Feature Lines via LISP, where it's a bit easier to quickly roll out individual commands for 'only grade between the first two vertices', or 'grade the entire Feature Line like this' as needed.

Plus, there's overhead associated with dynamic relationships - which means there's a tipping point where dynamic is advantageous over manually editing (even with LISP), and vice versa - the more complex/large drawings you need to grade, the more overhead associated with dynamic relationships.

I feel like the sweet spot that makes something like this beneficial at any scale, is the have a system for associating Feature Lines with specific 'Feature Rules' but perhaps use a custom sysvar to allow them to be dynamic or not, with a command to manually update the applicable values en-mass or via selection - that would give users the ability to test it for themselves on various sized projects, and see which works better for their needs.

HTH