Label Pipe Slope From Center-to-Center in Civil 3D

Title:

 Label Pipe Slope From Center-to-Center in Civil 3D

Issue:

y default, Civil 3D labels pipe slope using invert-to-invert, which is correct for hydraulic calculations but not ideal for plan/profile clarity—especially when working with shallow utilities, multiple drops, or treatment structures.

Many agencies and utility departments require designers to show slope based on centerline-to-centerline elevations, not invert-to-invert.

Civil 3D has no direct out-of-the-box label style that reports center-to-center slope, so designers often resort to manual calculations or static labels, which:

Break when pipes update

Cause drafting inconsistencies

Create conflicts in review packages

Increase rework during profile adjustments

Solution:

Use Civil 3D’s Part Dimensions and Expression-based label styles to compute pipe slope based on center elevations (crown or center-line), then display it dynamically in your pipe labels.

Step 1 — Expose Pipe Centerline Elevation Using Expressions

Civil 3D knows the pipe inside diameter, so we can compute the pipe center elevation using:

Expression for Centerline Elevation:

Centerline Elev = Invert Elev + (Inner Diameter / 2)

Create two expressions:

1. Start Center Elevation

Start_CL = StartInvertElevation + InnerDiameter / 2

2. End Center Elevation

End_CL = EndInvertElevation + InnerDiameter / 2

Step 2 — Create a “Centerline Slope” Expression

Now calculate the true slope between the two center elevations:

Expression:

CenterlineSlope =

(End_CL - Start_CL) /  (2D Length)

Format as percentage for labeling:

Format > Percent

Precision > typically 0.01%

Now this slope updates automatically whenever pipe elevation, size, or horizontal geometry changes.

Step 3 — Build the Label Style

Go to:

Toolspace > Settings > Pipe > Label Styles > Plan/Profile

Create a new label style ("Slope – Center to Center")

Insert a text component:

"Slope (C-C): <[CenterlineSlope(P3)]>"

Adjust formatting and drag state as needed.

Your label now reports true pipe centerline slope, even if diameters change or the pipe is dropped into a structure.

Step 4 — Apply the Label to Pipes

Apply the new label style to:

Plan labels

Profile labels

Pipe networks imported from GIS

Existing model pipes

The label updates automatically whenever the pipe is edited.