Feature Line Styles Control What?

So, sometimes you just simply forget a feature exists in the software. There’s just so much new stuff in the application that you are trying to learn with every release, and you get sucked into the big ticket items like Surface Simplify or improved Data Shortcuts. Then you’re sitting in a meeting one day, talking about something else and you mention a good idea for a new feature. The fun part is when the developer looks at you and says, "It already does that."

Then your whole development life flashes before your eyes, and you remember that, yeah, it does already do that, but I’ve forgotten that, and so has the person next to me, and the person you wrote the books with forgot too. Then you know it’s time to write a blog post and throw your ego up on a pole and simply say, "Oops."

So what’s the magic feature? The headline helps, but read more after the jump.

By now, most of you are familiar with the idea that feature lines within the same site react. For example, in this image, you see FL1 and FL2, both of the Basic FL style. FL1 is at 350′, FL2 is at 0. Where they cross, FL2 spikes up, creating a PVI in the FL.


Nothing magic about this. I make a few changes, and hey, something kicked in, and my FL1 has gone to 0 in the middle. That damned edit order has kicked in, and my elevations have gone wacky!


So, how to control this? Feature Line Styles. "What?" you say, "Feature line STYLES? Style just control display properties in C3D, they don’t control elevations!"

And you’d be right, except you’re wrong. Feature line styles actually have a priority, much like they do in Parcels. In parcels they really control priority of segments, so they control display. In Feature Lines, they control priority of segments, so they control elevation. So, to keep going in our example, I change the FL Style of FL2 to Flowline and FL1 to Grading. A nice color change, but nothing happens.


Here’s the magic. In Prospector, I expand the site, then get to the Feature Lines branch, right-click and select Properties as shown here.


This pulls up a dialog, one I’d bet a donut most of you have never been in. And it has a neat Otions tab, that even fewer of us have visited, shown here.


Notice how the FL objects look now, based on the order of the FL styles in the Options. I select Grading in the list, and use the blue arrow to push it to the top.


Now, I do have to admit, I had to leave the dialog, then re-enter to get this effect to happen, but you can see the change immediately. By setting a priority in the Site’s Feature Line’s Options, you can control which FL drives an intersection of two FL objects. And this can make all the difference in a happy day versus a frustrating day.

And thanks to the guys in NH for not laughing out loud for TOO long as Dana and I stared at each other with our mouths open as we recalled this neat feature. I’m hoping it will make your day easier too!


  1. Christian Barrett says:

    Nice! After reading this I’m reminded of this one fact; the more I learn, the more I know that I don’t know as much as I think I do!

  2. John Mayo, PE says:

    Excellent post James.

    Umm, I owe you a donut.

  3. Is this new in 09?

  4. Nice one James. I actually haven’t seen that new feature – I just wish if I named the featureline – the name would become be the breakline name…

  5. Yes, Mark, it is new to 2009.

    It’s one of those things that I remember seeing in testing, and Eric saw at Gunslinger, but it was just overshadowed by the bigger changes.

  6. John Barrus says:

    Wow. Sounds like this could be very useful. I’m going to have to look into it. Thanks.