Now, I’m not a big fan of the way Civil 3D handles contour labels, I think there are some alternatives that might work a bit better but, I don’t have much say in that so I’ve learned to handle what I’ve got.  When I’m showing contour labels in my classes, inevitably, someone asks, “Do those lines plot?”  Well, read on and I’ll explain to you what I explain to my students.

My first response is, yes, they do plot, if you want them to.  The trick is, how do I keep them from plotting?  I don’t know of anyone that would want these things to plot so what do we do.

Just Don’t Display Them

The first thing I show them is how to change the display of the contour label line directly.  There is no style that controls the display of the lines so you have to go into the properties of the line.  Select a label line, right click, and choose “Contour Label Line Properties…” (tip:  you can also pick Properties as they do the same thing).  In the AutoCAD Properties palette, you can change the display of the contour label lines to false.

If you want to change all the label lines in your drawing, you can select one, right click, Select Similar and then proceed as above.  You can also change the default settings for the newly created label lines.  To change the settings, right click on Surface under the settings tab and choose Edit Feature Settings…  In the dialog box, expand out Contour Labeling Defaults and change the value of Display Contour Label Line to false.

If you read the newsgroups a lot, this is the method you will see recommended most of the time.  Personally, I’m not a big fan of this method and here’s why.  If my surface changes and there is no longer a contour that crosses that label line, how can I tell if there is now a label missing?  If the line is displayed, I see a line sticking out in the middle of nowhere and it gives me a visual clue that something is amiss.  The only way to tell where there used to be labels is to select one and select similar.  If I have a lot of label lines, this doesn’t even work because I exceed the max display of grip points, so now I’m totally screwed.

Display Them but Don’t Plot!

So, I want to leave the contour label lines visible in my drawing but I don’t want them to plot, what do I do?  Well, my first thought was to simply turn the layer containing the contour label lines off.  I turned off the layer and everything looks great… until a regen.  Yup, after regening the contour labels disappear.  The labels layer is still on and the layer within the label style is still on, so why did the labels disappear?  I’m not sure but I have my suspicion which I’ll explain later.

Well, turning the layer off didn’t work.  What other layer tools do we have at our disposal?  We can set the layer to not plot!  What a great idea!  Change the pr0perty of the layer the label line is on to no plot… the labels remain.  Don’t get too excited because we’ve been here before with turning the layer off.  Do a quick regen and, YES!  The labels remain!  Submittal time roles around, you plot out your drawings and, NO LABELS!!!!!!!  Don’t believe me?  Try it yourself.

Here is my reasoning as to why the previous two methods don’t work.  When it’s time for Civil 3D to place the labels, it looks for label lines that cross contours.  Since the layer is turned off, there are no lines crossing the contours so no labels are placed.  If the layer is set to no plot, when you look at your drawing, you see the labels and that’s because the lines are drawn in the drawing and they cross a contour.  When you go to plot the file, the display of everything is regenerated and the no plot layers are skipped.  Since the label lines aren’t generated, no labels are placed in the drawing.  So what to do?

Here’s my solution:  use a color or plot style that doesn’t plot.  Yup, that’s it.  Talk about old school, huh?  In your .ctb file, choose a color and change it’s properties so when it’s plotted, no ink is put on the paper (likewise for the .stb file but instead of color, create a plot style).  Now, when it comes time to plot, the line is generated, it just doesn’t put anything on the paper so it looks like it’s off or set to no-plot.  And because the line is generated, the labels are placed as desired.  The nice thing about this is, I can see the label lines in my drawing and I can be clued in on missing labels without too much effort.

If you have any other methods for handling this, I would love to hear them.