Design and Manufacturing solutions through Digital Prototyping and Interoperability

# Civil 3D – Existing Pipe Network Tip

We often do not create any Pipe Networks to represent the existing utility mains in a project.  There is usually limited information on the correct depth of the utilities, even with a utility spot.  The best we can hope for is to draw the main in the plan view based on paint markings, and draw the crossings in our profile manually based on an approximate depth after a phone call to the respective agency.

On a recent design, not knowing the depth of the existing utility mains was a problem.  We have Force Main and Water Main running along and under a dirt road that will be paved.  Everyone is concerned that vibratory packing will cause a problem.  So they potholed the lines.

Now I have 3D point locations along 2 mains.  A pipe network would be best, so that it is easy to bring into my profile, and can be managed by styles. This presents a nuisance since the locations are on top of the pipes, and there are a lot of locations; that’s a lot of pipe edits.

Here is what I came up with.  Again, not rocket science, but I hope that it will help someone else.

• Style the points so that it is easy to discern them from others.
• Make the style respond to the elevations
• Create a 3D polyline from point to point
• move the polyline down the HALF (see below) the respective inner diameter plus one wall thickness.  I used he move command.
• Make sure the Pipe style prepared as desired, and the correct pipe size is in the Parts List.  Don’t forget the wall thickness
• Create Pipe Network from Object

### Half the diameter

The reason for this is that the Create Pipe Network from Object will use the elevation of the 3D polyline for the CENTERLINE of the pipe.  If you move the polyline down a full diameter, then the pipe will be created too low.  I mean to tell you that is a lot of edits.

If you did do this wrong, you can fix the pipe network easily.  Just expand the pipe network in the prospector, select the individual pipes (I highlight and pick ‘Select’ from the right click menu), and use the AutoCAD Move Command again.  Move it up HALF the pipe diameter.  Double check your values.

The wall thickness is somewhat negligible for structures like ductile iron, but I like consistency, so I add it.  If you are simulating RCP, then that thickness will be substantial.

That’s it.  Again, not rocket science, but the 3D poly really speeds things up.

Did you notice the wrong pipe linetype in the plan view?  10 seconds later it’s FM instead.  Another benefit of pipe networks in this case – 1 style can direct both Plan view and Profile view independently.

• Rita Davis

I have just read all thru this and am completely confused on what any of this means, but I am thrilled that my son, John Evans, understands what he is saying and I hope all of you at the University have a wonderful time and learn alot.