ArcGIS Pro 2.7 API Reference Guide
CreateEllipticArcSegment(Coordinate2D,Double,Double,Double,esriArcOrientation,SpatialReference) Method
Example 

ArcGIS.Core.Geometry Namespace > EllipticArcBuilder Class > CreateEllipticArcSegment Method : CreateEllipticArcSegment(Coordinate2D,Double,Double,Double,esriArcOrientation,SpatialReference) Method
The center point of the ellipse.
The angle in radians by which the ellipse is rotated from the x-axis. A positive value corresponds to counterclockwise rotation.
The length of the semi-major axis.
The ratio of the length of the semi-minor axis to the length of the semi-major axis.
The ellipse orientation, clockwise or counterclockwise.
(Optional) The spatial reference of the ellipse. The default value is null.
Convenience method to create a new instance of the EllipticArcSegment class. The new instance will build an ellipse.
Syntax

Parameters

centerPt
The center point of the ellipse.
rotationAngle
The angle in radians by which the ellipse is rotated from the x-axis. A positive value corresponds to counterclockwise rotation.
semiMajorAxis
The length of the semi-major axis.
minorMajorRatio
The ratio of the length of the semi-minor axis to the length of the semi-major axis.
orientation
The ellipse orientation, clockwise or counterclockwise.
spatialReference
(Optional) The spatial reference of the ellipse. The default value is null.

Return Value

Example
// Construct an ellipse centered at (1, 2) with rotationAngle = -pi/6,  
// semiMajorAxis = 5, minorMajorRatio = 0.2, oriented clockwise.
// Use a builder convenience method or use a builder constructor.

Coordinate2D centerPt = new Coordinate2D(1, 2);

// Builder convenience methods don't need to run on the MCT.
EllipticArcSegment ellipse = EllipticArcBuilder.CreateEllipticArcSegment(centerPt, -1 * Math.PI / 6, 5, 0.2, esriArcOrientation.esriArcClockwise);

// Builder constructors need to run on the MCT.
ArcGIS.Desktop.Framework.Threading.Tasks.QueuedTask.Run(() =>
{
  using (EllipticArcBuilder builder = new EllipticArcBuilder(centerPt, -1 * Math.PI / 6, 5, 0.2, esriArcOrientation.esriArcClockwise))
  {
    // do something with the builder

    EllipticArcSegment anotherEllipse = builder.ToSegment();
  }
});
Requirements

Target Platforms: Windows 10, Windows 8.1

See Also

Reference

EllipticArcBuilder Class
EllipticArcBuilder Members
Overload List