Monday, 6 February 2012

Copying Superelevation Data Between Alignments

In order to get C3D to automatically apply superelevation (SE) from the design criteria file you will need to have properly defined geometry on your horizontal alignment. That is to say that Civil 3D needs to see transitions and curves on the alignment to automatically apply the SE.

If you are using a surveyed road centreline (for overlay jobs for example) to define your alignment geometry you will probably not have defined curves and transitions on your alignment. This will be usually be the case if you create the alignment from a polyline. The polyline connecting the surveyed points consists of a series of straights. While we might know by looking at the alignment where a curve exists, Civil 3D only sees a series of short straights joining the points and will not be able to apply SE automatically from the design criteria file.

You can add it manually using the SE curve manager. To do this select the alignment and click on Superelevation on the ribbon< Calculate/Edit Superelevation < Open the Superelevation Curve Manager. Here you can manually add SE data. You will need to enter data for each curve and transition manually however which is cumbersome.

An easier way to do this is to create a best fit alignment from your surveyed road centreline, apply SE automatically to this alignment and then copy these values and paste them onto the actual road centreline alignment.

First create an alignment from the surveyed road centreline polyline as before. Then use the create best fit alignment tool to create an alignment from the same polyline. Your best fit alignment will have curves and transitions which you can tweak to match the existing road alignment. You can then apply superlevation to the best fit alignment as you normally would. (Select the alignemnt and click on Superelevation on the ribbon< Calculate/Edit Superelevation < Calculate Superelevation now).

If you then open up the SE tabular editor for the best fit alignment there is a new command (see below) in 2012 that allows you to export SE values to excel file.

Export the SE values from the best fit alignment. Open the tabular editor for the surveyed road centreline alignment and click import. We then have SE values applied to our surveyed road centreline for the existing horizontal geometry.

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