Problem:

When using the Define Vertical Curve Set tool, I would like to be able to calculate my vertical curve length by specifying a radius.  However, "Radius" is not one of the options available.

Solution:

The options used to calculate the vertical curve length differ depending on the curve definition (parabolic versus circular).

The options for parabolic alignments are:

• Length of Curve - specifies the length of the vertical curve.
• r=(g2-g1)/L - specifies the rate of change.
• Middle Ordinate - specifies the middle ordinate or external distance.
• Pass-through - specifies the pass-through point by station and elevation.
• K=L/(g2-g1) - specifies the vertical curves K.
• Unsymmetrical Length - specifies the length from the PVC to the PVI and the distance from the PVI to the PVC.
• PVC / PVTStation - defines the PVC station or PVT station.

The options for circular vertical alignments are:

• Radius - specifies the radius of the element.
• Pass-through - specifies the pass-through point by station and elevation.
• Tangent - specifies the tangent of the element.

If you do not see "Radius" listed as an option, this means that your vertical alignment has a parabolic definition.  This can be verified by locating the vertical alignment in the InRoads Explorer menu.  If you right-click on the alignment name, you will be able to see which curve definition is being used.  You can also choose to change the curve definition from this same menu if you wish.