Contour “Hooks” into Existing Grade

This one’s for Lucy since she inspired the idea. Many users have to place small glyphs, ticks, dots, whatever as “hooks” into the existing ground when showing proposed surfaces. It’s a bit of a hassle, but with a little labeling trick, you can get 90% of them done almost automatically. Make the jump to see my solution.image

Once you have your proposed surface, it will probably look something like this image.

Now you can spend your time and insert a little block or dot or whatever…or you can label. I’ve made a contour label style called DOT that’s simply a dot block centered on the line with no masking turned on. Here’s what it looks like in the middle of the contour.


Now, I need to put this label on the end of every contour, right where the contour ties to the existing ground. To do this, I’ll first extract the boundary of the surface by changing my surface style to display a border, then extracting that using the tool on the Surface Tools panel.

To make life easier, you’ll want to set the border as a flat line as part of the style. When you set your style as shown here, the extracted polyline will be a LWpoly, all the easier to manipulate.


Now that you have a polyline to play with, turn your border display back off. Offset the polyline a VERY small amount so that it sits just inside your proposed surface. I used .025 for example.

Now, pull up your Surface label dialog and set the DOT style as shown here and click Add.


One of the options many people ignore is the ability to use Objects to label. Follow the prompts at the command line and instead of drawing a new line, simply select the polyline we made and then offset. Right-click to finish the selection, and you’ll have this:


As you can see, there are some spots you’ll need to play with, and you’ll want to turn off the contour label line display. After a little tweaking, here’s how my surface display turns out:


You can use almost any block, or you could use this technique to label all contours along the outer edge with normal labels. I’d also suggest you weed the polyline before turning it into a contour label line!

It’s been a busy week, got to see some great folks, but it’s time to go home. Have a great weekend!


  1. Rick Graham says:

    Nice tip! However this only works some of the time and only with grading objects projected to a surface. If you do it any other way there is a good chance that your proposed contours won’t hit the existing due to triangulation. At least this has been my case. My ‘workaround’ to this is to have my running osnap set to Apparent Intersection and then add points where the proposed and existing contours meet. Not an exact science yet. 🙂

    • Drape a FL along the surface 1″ from the daylight, make it part of the proposed surface, and they all hook just fine. You’ll need to update with revisions, but it’s not much of a moving target, EG is EG.