Tuesday, 21 August 2012

Creating a Profile from Single Line of Points

I have come across this situation a number of times, particularly when working with water schemes where you might have a single line of survey points for a number of kilometres along a road.
What is the quickest/easiest way to create a profile along the surveyed points? One way is to use the Create Profile from File command. You will need the point file in a particular format before we can use this command however. We need the point information in chainage and elevation rather than easting, northing and elevation from the surveyed points.

First join the points with a 3D polyline. The points are in numerical order so we can speed the process up by using a transparent command. Type 3DPOLY at the command line and when prompted to specify first point type 'PN for the point number transparent command. Then type the points you wish to join, 3-102 in my case and the points are joined instantly.

Next create a featureline from object and select the 3D polyline. Untick the option to delete the existing entities - we will use the polyline again to create an alignment along the points.
Select the featurline, choose Edit Elevations from the ribbon and then right click in the dialog box and select Copy All. (You will notice that we have the information we need in this dialog box as well as some extra we can delete in excel.)
Paste the chainage and elevation columns into excel and edit the file to suit the requirements for the profile from file command - see help menu. When you have only the information required, paste into Notepad.
Back in Civil 3D we need to create an alignemt for our profile. We will turn the 3D polyline into an alignment - first we must turn it into a 2D polyline. Turn on your drop down menus at the top of your screen (type MENUBAR at the command line and set the value to 1). On the grading menu select Polyline Utilities and then Convert 3D to 2D Polylines.
Next use the Create Alignment from Objects command to turn the 2D polyline into a Civil 3D alignment (we need this in order to create our profile). Now use the Create Profile from File command.

Select the alignment just created and the point file and click ok.

Select the alignment and choose Profile View from the ribbon to complete.
When creating the water network in plan it is useful to know where the high and low points on the road are for placing the air and scour valves. you can add labels to the horizontal alignment that indicate where these points on profile are. First you will need to create a best fit profile from the profile just created. (the best fit profile will have proper geometry - curves and straights - as opposed to just a series of straights joining the surveyed points).
Next select your horizontal alignment in plan, right click and select Edit Alignment Labels. Add in Profile Geometry Labels and select to label the high and low points as below:
This labels the profile high and low points in plan...

1 comment:

  1. Good post - Incidentally the 3D to 2D conversion can also be found on the ribbon Modify and then hit Design and select from the flyout