Public Function AddTangent( _
   ByVal Element1 As Object, _
   ByVal Element2 As Object, _
   ByRef ConstrainingPoint1() As Double, _
   ByRef ConstrainingPoint2() As Double, _
   ByVal Offset As Double, _
   ByVal IsHalfSpacePositive As Boolean _
) As TangentRelation3d