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Table Of Contents
Chapter 3 Working with Profiles and Vertical Alignments
204
The following illustration shows the parameters used in calculating a vertical
curve based on the Through Point option:
Drawing a vertical curve through a point
Drawing a Sag Vertical Curve Based on
Headlight Data
One method of drawing a sag vertical curve is to specify a headlight
sight distance.
To draw a sag vertical curve based on headlight data
1
From the Profiles menu, choose FG Vertical Curves to display the Vertical
Curves dialog box.
NOTE
You can only use this command with a sag curve.
2
Select the Headlight option by clicking its name in the Description list. You can
also click the Headlight icon, and then click OK.
NOTE
If you do not see the graphic representation of the curve type you want to
create, then click the Next or Previous button at the bottom of the Vertical
Curves dialog box.
3
Select the tangents that represent the grades going into and out of the PVI.
4
Enter the value for the headlight sight distance.
5
Press ENTER to accept the default values for the headlight height above
pavement and maximum headlight angle, or enter new values.
The length of the curve is calculated.
6
Press ENTER to accept the calculated length of curve, or enter a new value.
If you enter a new length, the Headlight option recalculates the headlight sight
distance and draws the curve with the length specified. The final headlight sight
distance appears and the command draws the curve.