Creating a Waterline at a Constant Depth

I was writing some new EE training material and was searching for a snappy way to create a waterline that was at a given depth below the ground.  After a few different approaches that just didn’t feel easy enough I came across a great solution!

It turns out you can create a pipe network from lots of different objects, including a feature line.  So I thought….what if I created a feature line, assigned elevations to it from a surface, dropped it 4 feet (or whatever) to set the depth, and then made it into a pipe network?  Well guess what…it works great but you have to know about two key boxes that need to be checked along the way.

Here are the basic steps:

1.  Draw a polyline along the path of the waterline.

2.  Launch the Create From Objects command on the Feature Lines toolbar.


3. While running through the Create from Objects command be sure to check all of the Conversion Options.  You’ll need them all, especially Weed Points (key check box #1).  This will keep you from having hundreds of short pipe segments.


4.  Assign elevations from the appropriate surface.  For cases where your waterline passes through existing and finished ground, you’ll want to have a composite surface.


5.  On the Weed Points dialog, use only the Length option and enter a length that makes sense.  As you can see here, I used 25 feet.  Notice how my waterline would have had 152 vertices without this option and will now only have 9.


6.  Now that the feature line is in place you can right-click it and use Raise/Lower to drop it to the depth you need.


7.  Finally, use the Create Pipe Network from Objects command to turn the feature line into a pipe network.


8.  This brings us to key check box #2: Use vertex elevations.


The rest is history…


Of course this approach can be used for anything underground that parallels the ground surface (gas line, conduit, etc.)



  1. Dale Miller says:

    This is very cool. I do have a question though. When eliminating vertices, does the straight line section still remain +4 feet below grade at all points? Seems like depending on which vertices are picked, it could potentially draw a line between two points that could cross the 4 foot barrier.. effectively cutting the corner short.

  2. Yeah, if you do not weed vertices you’ll have a perfect 4′ depth at every point along the waterline but you’ll also have a ton of pipe segments (152 in the example above). That’s where judgement comes in. You can always add a network node if there is a spot or two where it has cut the corner too closely. Good point!

  3. Eric, I’m so glad you posted this process. We’ve been do it this way for a while now. It works really well. When revising at Pipe Network horizontally, we turn the Null Structure’s on and move them. It’s still a bit of a challenge to update each vertice and invert if a long run of pipe moves.

  4. JOHN GIBLIN says:

    I’ve been using this method for some time to create water line projects. On a small project I’ll draw the feature line at pipe intersections and laterals to keep the number of null structures down. I also set my pipe rules to cover only and structure rules to 0.00 sump and have my structure style for the profile block to have an insertion to the bottom of pipe. I would like to see Autodesk add more water line options

  5. Erik Boe says:

    When I try to “Create Pipe Network from Object”, the “Structure to create” box is grayed out, even though I have a Null Structure in my parts list. Also grayed out is the “OK” button. Any idea why this would be the case?

  6. I remember that being an issue in Civil 3D 2008. Apparently you need some kind of “real” structure on the parts list. It’s pretty dumb.

  7. also note that the feature line elevations are applied to the pipe CENTERLINE elevation, not the invert, so be sure to accomodate your pipe diameter when raising/lowering.

  8. dave benda says:

    This post is great I just have one question, when you have an intersection where your water pipe splits off in a different direction how do you connect them, would you just edit layout and draw the rest in from that junction or is their a way to add multiple feature line object selected utilities to the same network?