How To Create Dynamic Pipe Labels for Crossing Pipe Stations and Inverts

[cpennetti]

I started to design in Civil3D recently, and was frustrated by Civil3D not being able to show information related to crossing inverts and elevations, but there's enough variables to create an expression that i think can do it... 

Ok, so this is my thought:

Civil 3D has the ability to provide variable of a crossing pipe's starting structure station, ending structure station, and then starting offset and ending offset right?  So if you think about it from plan view, you've created a triangle based on that information, with respect to the crossing pipe and the profiled pipe.  So if you could figure out the distance from the starting station to the crossing point, you could add it to the starting station, and then get a crossing station which could be done by relating similar triangles

For land development engineers, we tend to show profile of the pipes, and then call out the sta/inv of crossing pipes, so our pipe is the alignment, and is then profiled.

So, if we use a custom expression under settings, pipe, label styles, plan profile, and then new expression, we can use the variables described above, to create a new pipe label option (which will show up in the pulldown menu once your expression is created).

Crossing Station Expression:

IF({Pipe Start Station}<{Pipe End Station},{Pipe Start Station}+{Start Offset}*(({Pipe End Station}-{Pipe Start Station})/({Start Offset}-{End Offset})),{Pipe End Station}-{End Offset}*(({Pipe Start Station}-{Pipe End Station})/({Start Offset}-{End Offset})))

The reason for the IF statement is because of the possibility of direction of pipe crossing

For Crossing Invert, we can use some 3rd grade math, using Pythagoras theorem, consider the same idea, using the new length that we've just discovered, and determine the hypotenuse, then use the slope, and the starting/ending invert

Crossing Invert Expression:

 IF({Pipe Start Station}<{Pipe End Station},{Start Invert Elevation}-({Pipe Slope}*(SQRT(SQR({Start Offset})+SQR(IF({Pipe Start Station}<{Pipe End Station},{Start Offset}*(({Pipe End Station}-{Pipe Start Station})/({Start Offset}-{End Offset})),{End Offset}*(({Pipe Start Station}-{Pipe End Station})/({Start Offset}-{End Offset}))))))),{End Invert Elevation}+({Pipe Slope}*(SQRT(SQR({Start Offset})+SQR(IF({Pipe Start Station}<{Pipe End Station},{Start Offset}*(({Pipe End Station}-{Pipe Start Station})/({Start Offset}-{End Offset})),{End Offset}*(({Pipe Start Station}-{Pipe End Station})/({Start Offset}-{End Offset}))))))))

I can't say i've tested it to death, and it might be worth trying some unusual conditions, such as a modeled waterline pipe that might have a negative slope and such, but this is my first shot at how this can all be done.

The final step is to create a label style with these new expressions, and then apply the label to one of your crossing pipes (showing the crossing display information).  Be sure to select similar all of your labels, and in the label properties, choose the alignment to be the alignment that the crossing pipe is being displayed on.

Someone might want to double check my equations, maybe we throw in some absolute values, but the philosophy is sound i think...

Thoughts? 

-Cody

[Civil3DReminders]

I remember going down this path, but if I remember correctly I started having issues once the alignment had a curve or if my crossing pipe was curved.

Christopher

http://blog.civil3dreminders.com/

[cpennetti]

Hm, it did seem too easy, but I hadnt seen it posted so I wasnt sure what issues there might be.

Thinking through the curve issue, it would also have a problem if the starting crossing structure existed on a separate leg of the pipe that's it's crossing, thereby eliminating the triangle setup... Is there a way for the crossing pipe to recognize where its starting/ending structure is in relation to the pipe that it's crossing?  Have you guys looked into that, and is there a discussion open about this method?

I wonder if the curve issue could be resolved through angles and arc lengths, but i have to remember how civil3d treats curved pipes/alignments... mainly concerned about pipes 

[Anonymous]

If you just want to know station at a crossing, use a null structure with no display in profile view.  You are basically drawing things twice but it makes stationing at crossing a little easier and dynamic.

[Anonymous]

I tried using the expressions  you posted for crossing station & inverts under my Label styles>Plan profile and then used that expression in my pipe label, but the expression nevers displays in my label style. I can't figure out how to make this work. If you have time to help I would appreciate it.

Now, I don't want to take without giving, so here is a expression & pipe Label style that I use on my sewer profiles when I have to annotate my profiles in "soft' metric. It's simple but still useful.

Expression for Pipe "soft" metric size:

Name: Metric Equiv. Pipe Size

({Pipe Inner Diameter or Width}*12)*25.00

Contents for Pipe "soft" metric label style:

<[2D Length - Center to Center(Uft|P2|RN|AP|Sn|OF)]>' [<[2D Length - Center to Center(Um|P2|RN|AP|Sn|OF)]>M] - <[Description(CP)]> [<[Metric Equiv Pipe Size(P0|RN|AP|Sn|OF)]>mm] @ <[Pipe Slope(FP|P2|RN|AP|Sn|OF)]>

Thanks,

Paul
 

[emgerecke]

Why can't they just add Crossing Pipe Station for the plan label expressions like they do for the profile label styles? Seems like a simple update and frankly not sure why this wasn't done to begin with....

[Jerry_Barnes]

Like many of the "why didn't they just do this?" questions we all have for Civil 3D, the quickest solution is, unfortunately, often found in third-party software. (We use RTC Pipe Network Tools with many commands for simplifying pipe work, including pipe crossing labels for plan view.) Third-party tools can be a great idea... right up until the cost part. 

[brian.strandberg]

So far Dynamo seems to be the best option.  This one is a good start: https://www.youtube.com/watch?v=h4bvFdrowGM