Create a Transition Curve by Tangent, Length and Radii

Description

Create a two dimensional transition curve by tangent bearing, curve length and radii.

Access

Home / Tools / Create / Line or Polygon / Transition Curve / Tangent, Length and Radii

Requirements

Solve Module.

Controls

Control	Description
Name	Type a name for the generated object or click to increment to the next available name. See Naming Options below.
Type	Select the type of transition curve. Bloss - Curve with non linear curvature variation (non-spiral). Clothoid - Approximation of the Euler's spiral. NSW Cubic Parabola - A modified cubic parabola specific to the Australian New South Wales RailCorp.
Create partial transition curve	Select the checkbox to create a portion of the transition curve.
From	Input the from vertex for the transition curve segment.
Tangent Bearing	Select one of the following methods to input the tangent bearing. Entry Tangent Bearing - Indicates that the From vertex is the location on the transition curve where the radius is a maximum. Input the transition curves entry tangent bearing. Exit Tangent Bearing - Indicates that the From vertex is the location on the transition curve where the radius is a minimum. Input the transition curves exit tangent bearing. Note: This bearing is a local plane bearing when the direction type is configured to Local Plane.
Curve Length	Input the 2 dimensional transition curve length.
From Radius	Input the radius at the start of the transition curve. Note: Available when the bearing input method is configured to Exit Tangent Bearing
To Radius	Input the radius at the end of the transition curve. Note: Available when the bearing input method is configured to Entry Tangent Bearing
Height Method	Select one of the following methods to input a height for the vertex at the end of the line: Default Height - Use the default height for the created vertex. Grade (%) - Grade as percentage from the from vertex. Grade (1:) - Grade as a ratio from the from vertex. Height - Height of the created vertex. Height Difference - Difference in height from the from vertex.
Clockwise	Specify the direction of the transition curve: Select the checkbox to draw the transition curve in a clockwise direction. Clear the checkbox to draw the transition curve in an anticlockwise direction.

Notes

Click OK to add the transition curve segment to the constructed line. Click End to create the line.
Relative heights are computed from the from Vertex.
Select or clear the Clockwise checkbox prior to inputting other values.
The geometry of a line containing a transition curve can not be viewed or edited when a User Coordinate System is applied.
The curve distances is used to compute the vertices height when the Grade (%) or Grade (1:) height method is selected.
When creating an alignment, this tool is available providing the horizontal design standard in the create options is configured to 'None'.