ArcGIS Pro 2.8 API Reference Guide
CreateEllipticArcSegment(MapPoint,MapPoint,Coordinate2D,SpatialReference) Method
Example 

ArcGIS.Core.Geometry Namespace > EllipticArcBuilder Class > CreateEllipticArcSegment Method : CreateEllipticArcSegment(MapPoint,MapPoint,Coordinate2D,SpatialReference) Method
The point from which the arc starts.
The point to which the arc ends.
An interior point on the arc.
(Optional) The spatial reference. If spatialReference is null, then the spatial reference is inherited from startPt or endPt.
Convenience method to create a new instance of the EllipticArcSegment class. The new instance will build a circular arc from three points.
Syntax
Public Overloads Shared Function CreateEllipticArcSegment( _
   ByVal startPt As MapPoint, _
   ByVal endPt As MapPoint, _
   ByVal interiorPt As Coordinate2D, _
   Optional ByVal spatialReference As SpatialReference _
) As EllipticArcSegment

Parameters

startPt
The point from which the arc starts.
endPt
The point to which the arc ends.
interiorPt
An interior point on the arc.
spatialReference
(Optional) The spatial reference. If spatialReference is null, then the spatial reference is inherited from startPt or endPt.

Return Value

Exceptions
ExceptionDescription
Incompatible spatial references.
startPt or endPt is null.
Example
// Construct a circular arc from (2, 1) to (1, 2) with interior pt (1 + sqrt(2)/2, 1 + sqrt(2)/2).
// Use a builder convenience method or use a builder constructor.

MapPoint fromPt = MapPointBuilder.CreateMapPoint(2, 1);
MapPoint toPt = MapPointBuilder.CreateMapPoint(1, 2);
Coordinate2D interiorPt = new Coordinate2D(1 + Math.Sqrt(2) / 2, 1 + Math.Sqrt(2) / 2);

// Builder convenience methods don't need to run on the MCT.
EllipticArcSegment circularArc = EllipticArcBuilder.CreateEllipticArcSegment(fromPt, toPt, interiorPt);

// Builder constructors need to run on the MCT.
ArcGIS.Desktop.Framework.Threading.Tasks.QueuedTask.Run(() =>
{
  using (EllipticArcBuilder cab = new EllipticArcBuilder(fromPt, toPt, interiorPt))
  {
    // do something with the builder

    EllipticArcSegment anotherCircularArc = cab.ToSegment();
  }
});
Requirements

Target Platforms: Windows 10, Windows 8.1

See Also

Reference

EllipticArcBuilder Class
EllipticArcBuilder Members
Overload List