public override bool Intersect(IBoundingBox bB,out Vector hitPoint)
 {
     return bB.CircleIntersect(this,out hitPoint, new Vector(0,0));
 }
 public override bool Intersect(IBoundingBox bB,out Vector hitPoint, Vector velocity )
 {
     return bB.CircleIntersect(this,out hitPoint,velocity);
 }