Expressions and Cross Sections

Civil 3D can be fairly complicated at times. Often times lots of work may need to be done in order to get stuff to look correct. Take this image for instance.

The arrows are pointing in the wrong direction and the slope labels are not consistent if we want the lane to show a constant slope value of –2%. To fix this we need to create some expressions or use some that are already available.

The first expression is the Grade Check Expression. This can be found in the _AutoCAD Civil 3D (Metric) NCS.dwt template. If you don’t have it the expression value is:

IF({Link Grade}<0,0,pi)

This will rotate the arrow to the downslope and is placed in the Rotation Angle of the label component.

The next expression is to label the slope the same for both sides. This will use an expression to see if the slope is positive and then multiply the grade by 1 or –1 to get the desired slope.

IF({Link Grade}>0,-1,1)*{Link Grade}

Then add the expression to the text component.

I’d use a label name to apply to what code you want to change, in my case Flat Grades-Pave. Then in the code set style apply the correct label style to the link code.