Examine Spiral

(This functionality is available with the Computations module)

Examines the dimensional attributes of a spiral object.

The Examine/Spiral command is selected from the Computations task.

Examine Spiral dialog box

Item	Used to
Spiral Number	Select the required spiral. The line number can be entered via the keyboard or the spiral can be selected via the mouse.
Examine	Displays the dimensional attributes.

Attribute	Description
Start Radius	The starting or maximum radius of the spiral. If the spiral is a full spiral, this radius is infinite.
End Radius	The ending or minimum radius of the spiral.
Length	The distance along the spiral.
Full Spiral Length	The distance along the spiral from the point of infinite radius. For a full spiral this is the same as the length.
Tangent Direction	The direction of the tangent at the beginning of the spiral.
Shift	This is applicable when a spiral is inserted between straights and a circular curve, partially replacing the circular curve. It is necessary in introducing the spiral, to shift the circular curve away from the straights by an amount known as the shift. If the curve is a part spiral this value is not applicable.
Minimum Spiral Angle	Also known as the minimum tangential angle, this is the spiral angle at the start of the curve. For a full spiral, this value is zero.
Maximum Spiral Angle	Also known as the maximum tangential angle, this is the spiral angle at the end of the curve.
Maximum Deflection Angle	This is the angle of deflection from the starting tangent to the end of the curve.
Chord Distance	The straight line distance from the start of the spiral to its end point.
Long Chord Distance	The straight line distance from the point of infinite radius to its end point. For a full spiral this is the same as the chord distance.
Start Point	The start point co-ordinates.
End Point	The end point co-ordinates.
Velocity	The maximum velocity at the exit of the curve based on the current LISCAD settings.

Start Point:- S End Point:- E Length:- S-E along the curve Tangent Direction:- S to T Maximum Deflection:- Angle T-S-E Chord Distance:- S-E End Tangent Direction:- I to E Spiral Angle:- T-I-E This is the difference between the maximum and minimum spiral angles.