This .NET class wraps the AcGiShadowParameters2::ExtendedLightShape ObjectARX class. 

It gives the collection of shape of the extended light source.

Public Enum ExtendedLightShape
  Linear
  Rectangle
  Disk
  Cylinder
  Sphere
End Enum

public enum ExtendedLightShape {
  Linear,
  Rectangle,
  Disk,
  Cylinder,
  Sphere
}