I recently found an old InRoads video that shows what I am trying to achieve in ORD. I want the ditch to show when the existing grade slopes toward the road and a fill slope when it falls away. The video used the template below. When the slope is below LT_DTCH_BS it has a fill slope. When above, it draws the ditch.
Here's a link to the video: https://youtu.be/FvlgMV3_eWA?t=854
At its most basic, exactly what you have shown here, you would create a component that stops at LT_DTCH_BS. then add the end conditions to that. The fill EC, which would have the higher priority, would continue down to existing surface. If that doesn't solve (because I would be in the cut condition) the second priority EC would draw the ditch.
But that begs the question of where you would put LT_DTCH_BS. If you don't have a fixed point (like a grade break hinge or minimum slope length) it could get more complex. If that's the case, you may want to create one end section just to hit existing ground. Then you could create a null point further out on your existing surface. Then you can use vertical Max-Min between that and your tie point to control whether a ditch is drawn.
MaryB
Power GeoPak 08.11.09.918Power InRoads 08.11.09.918OpenRoads Designer 2021 R2
Seeing what I saw of the video, I believe that the ditch is not where this control is. I suspect it is part of the fill slope end sections, so you may need to watch earlier in the video to see what control they used.
It definitely looks as if there is a null point at the end of the ditch as I mentioned below.
I found the previous video and they make it work by creating a vertical offset of 0.1 from the intersection of the foreslope. I would have never figured it out this way, but it works.https://youtu.be/WqFKY-0Q9TU?t=2154
I'm glad you found that! Thank you for sharing.