The Location module supports parabolic vertical curves.
Parabolic curves are defined by the K value: the length of curve divided by its change in grade %. A vertical curve that goes from 2% grade to 6% grade in 40 m. has a K value of 10 m./% (40 m./(6%-2%)).
A vertical curve is defined by the vertical point of intersection (VPI ) of two tangent lines. The Begin Vertical Curve and End Vertical Curve (BVC and EVC) points are inserted at the time the curve is created and can not be edited by the user except through the use of the Vertical Curves Panel.
To create a vertical curve:
1. Display the Vertical Curves Panel by selecting View | New Window | Vertical Curves or by clicking the button on the Standard toolbar.
2. Create an alignment containing three or more vertical points of intersection (VPIs) (see Interactive Operations).
3. Move the current point to the desired VPI (you may use the buttons in the Curve Panel). The IP and Tangent Parameters will be updated in the Vertical Curves Panel.
4. Select the Parabola radio button, then type in the desired K or Length value. If the value you type in is larger than the maximum allowable, a warning message will be displayed and the Apply button will be disabled.
5. After pressing Apply, the Location module generates a curve (including BVC / EVC points) and then updates the earthworks in the affected range. Steps 3,4,5 can be used as many times as necessary to change existing curves.
To remove a curve:
1. Display the Vertical Curves Panel by selecting View | New Window | Vertical Curves or by clicking the button on the Standard toolbar.
2. Move the current point to the desired VPI (you may use the buttons in the Curve Panel). The curve parameters will appear in the Vertical Curves Panel.
3. Select the No Curve radio button and press Apply.
button on the Standard toolbar.
buttons in the Curve Panel). The