Use x1,y1; x2,y2; start and sweep angles to extract arc x3,y3 and x4,y4 points.
protected Void CalcArcPoints(Int32 X1,
     Int32 Y1,
     Int32 X2,
     Int32 Y2,
     Double startAngle,
     Double sweepAngle,
     Int32& X3,
     Int32& Y3,
     Int32& X4,
     Int32& Y4)

See Also

Graphics3D Class | Graphics3D Members | Steema.TeeChart.Drawing Namespace