Level Curves from Polylines (2 Step)

In the previous post Had georeferenced An image containing contour lines, now we want to convert them to contours of Civil 3D.

Digitize curves

For this there are programs that almost automate the process, such as AutoDesk Raster Design, equivalent of Descartes in Bentley or ArcScan at ESRI. In this case, I am going to do it on foot, drawing polylines.

They should not be done with Smartlines, But with normal polylines.

It is recommended to create levels with the names of the main curves. Help for visual aspects.

It is preferable to work with lines of thickness of 0.30 to be able to visualize the advance.

To view the line thickness, the LWT button must be activated.


Smooth and join curves.

This is not always necessary, but for educational purposes, let's see how it's done. It happens that some polylines could not be joined because the command was interrupted, or we made some vertices a bit of race that do not behave with the curve.

  • The edit polyline command is activated Pedit
  • The multiple option is selected, with the letter M and then enter
  • All the polylines that we hope to treat are selected
  • We use J to join
  • We use S to soften

Civil curves1

Assign elevation to polylines
You have to touch the curves, one by one, activating the properties and assigning the corresponding elevation. In this case, since they are every 25 centimeters, the green curve would be 322, and the following for Curves ciil2To get to the blue would be 322.25, 322.50, 322.75

In the case of the celestial ones, see that criteria are used to know how the behavior of that area is. For this reason, the main ones should be put in a different color.

You can check that all were elevated, seeing an isometric view.

View> 3D Views> NE Isometric.

Civil curves3

Convert the polylines to contour lines.

To do this, we go to the left panel, in the tab Prospector, And we created a new surface, type TIN.

Here, once the surface is created, you can see the properties, among which appears Masks, Watershedsand Deffinitions. This is where the criteria for contour lines appear (Contours).


Right-click on Contours, then Add.

In the description we will put Scanned Curves, and then do ok. Then we select all the polylines that we have digitized.

See how from there, triangulation is generated.

Adjust the properties of the curves.

One detail remains that causes despair when it is done for the first time. And it is, that the contour lines seem to be not visible, but it is a matter of Display properties.

To do this, right-click and select Edit surface style. In this panel, we choose the tab Contours. In Contour Intervals, We choose the same interval as the map scanned, to check if everything went well.

The main curves for each 1.00 and the secondary curves for each 0.25.


And there it is. It is clear that the extremes there is treatment to do, because the program tries to close the Boundary assuming there is no continuity with another sheet. We'll see if in another post we compare it with Google Earth data and promote the tourist destination of friends Pipiles.

Civil curves4


3 Replies to "Contour lines from polylines (Step 2)"

  1. Hi, I'm new to this civil3d and I had a problem because they gave us some level curves in another dwg file format or an old autocad format in which we can not work in the civil 3d I would like to know the steps to convert those files to the most current version of civil3d so that we can work as if they were level curves without the need to use an autodesk file converter thanks in advance.

  2. Yes, when you have a lot to digitize Raster Design is a great help.


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