Create a Circular Arc by Start, Centre and Distance

Description

Create a circular arc segment by start and centre vertices, and arc or chord distance.

Access

Home / Tools / Create / Line or Alignment or Polygon / Circular Arc / Start, Centre and Distance

Requirements

Controls

Control	Description
Name (Line or Alignment)	Type a name for the generated object or click to increment to the next available name.
Start	Input the start vertex.
Centre	Input the centre vertex.
Distance	Select one of the following methods to input the distance from the Start vertex. Arc Distance - Input the arc distance. Chord Distance - Input the chord distance.
Height Method	Select one of the following methods to input a height for the end vertex: Default Height - Use the default height for the end vertex. Grade (%) - Grade as percentage from the start vertex. (Valid for 2D arcs only) Grade (1:) - Grade as a ratio from the start vertex. (Valid for 2D arcs only) Height - Height of the end vertex. Height Difference - Difference in height from the start vertex.
3D circular arc	When creating circular arcs do one of the following: Select the checkbox to compute the circular arc in 3 dimensions. Clear the checkbox to exclude the vertices heights from the arc calculations.
Clockwise	Specify the direction of the arc: Select the checkbox to draw the arc in a clockwise direction. Clear the checkbox to draw the arc in an anticlockwise direction.

Notes

Relative heights are computed from the start vertex.
Click the Components tab prior to clicking OK to view the values computed for the arc.
If 3D is cleared:
- Distances input are interpreted as 2 dimensional distances.
- Heights are not used to compute the arc components.
- The arc distance is used to compute the vertices height when the Grade (%) or Grade (1:) height method is selected.
- Lines will display as a circular arcs in the Plan view.
- Vertices heights are used to display the curve in 3D view.
When creating an alignment:
- You can create 2D circular arcs only.
- This tool is available providing the horizontal design standard in the create options is configured to 'None'.