How to Generate Contours

In Civil Designer, there are 2 methods available for the calculation of contours.

The default method is quick contours - in this method Civil Designer dynamically calculates the contours. This means that as you modify the breaklines or move points, the contours will update automatically. The second method is generated contours - in this method the contours are stored in a contour file, and therefore the contours are not updated dynamically.

The beauty of the generated contours is that it dramatically improves the re-draw speed of large projects because instead of recalculating the contours during the re-draw the program reads the contour file. Generated contours can also be labeled.

Due to the different way the 2 methods calculate the contours, on certain projects, the generated contours might look a little strange. A common problem for generated contours is a strip survey, with a large open area in between (contours will cross over the open space).

Below is a figure of a typical site with quick contours. Note how the contours are only drawn where there is data.

The following figure shows the same site, now using generated contours. Note the open area where the generated contours cross the open space.

To overcome this problem, exclusion polygons need to be used.

Select the Terrain Mode and the Model › Define Polyfence option.

Click within the area that needs to be excluded, Civil Designer will shade the selected area and allow you to name the polyfence. Multiple polyfences can be defined.

If the polyfence needs to be deleted use the Model › Remove Polyfence function.

Once the polyfences have been defined generate the contours again with the Terrain › Contours from lines option.

Make sure that the Use exclusion polygons option is selected and click OK to continue.

A dialog will appear listing the polyfences in the project, the user can select which polyfences to use (multiple selections are made by holding down the shift key and left clicking with the mouse)

Click OK to continue.

The generated contours are now re-calculated using the exclusion polyfences.

Note that the open area no longer has contours crossing over.

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