Civil 3D Alignment Labels that Flip Out, in a Good Way

The Issue:

During a recent template creation, a client wanted perpendicular, Station/Offset labels for the Left and Right side of an Alignment that would automatically flip, as the default would only maintain its original reference rotation. 

The Goal:

Instead of duplicate labels for ALL the label options we wanted to create something smart enough to know what side of the Alignment the label was at and automatically flip/rotate.

The Technique:

A few things went into the making of this dynamic label as there is no default embedded function within the label, we had to approach the solution via an Expression.  Initially I attempted to use the “Side” property, but it did not work as expected.

The solutions were achieved with an expression, called “Side”:  DEG2RAD(IF(Offset<0,0,180))

1. Use the “Offset” value, negative or positive to determine left (-) or right (+) side,
2. Embedded with an “If” statement that will issue a 180 flip when greater than (<) Zero Value
3. And because the way Civil 3D calculates angles, I added a DEG2RAD function.

We then also wanted to add a gap (0.01) to space the Label from the Marker and built another expression based upon the same idea as above, called “Ofst”:  IF(Offset<0,0.01,-.01)

The Expressions can be seen below from the Toolspace > Settings tab > Alignments > Labels > Station and Offset

The label style itself used the “Side” expression for its Rotation Angle and the “Ofst” expression for the Y offset value

I hope you guys have fun with this simple and awesome way to create smart Alignment Offset Labels and this serves as a reminder of what Expressions can do for you.

About the Author

Civil Solutions Team Manager<br><br>Kevin is responsible for managing a team of Technical Engineers who educate and support Autodesk products for all AEC Engineering Services. He has 40 years of industry experience specializing in public sector surveying and right-of-way needs for infrastructure improvement projects and Global Positioning System (GPS) surveying services. Kevin’s 40 years of experience also includes management and field surveying experience on hundreds of transportation, site development, environmental, and construction projects throughout Ohio.

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