Sub Example_PrincipalDirections()
    'Этот пример создает поле в пространстве модели.
    'Затем возвращает PrincipalDirections для этого поля.
              
    Dim boxObj As Acad3DSolid
    Dim length As Double, width As Double, height As Double
    Dim center(0 To 2) As Double
    
    'Определите поле
    center(0) = 5#: center(1) = 5#: center(2) = 0
    length = 5#: width = 7: height = 10#
    
    'Создайте объект поля (3DSolid) в пространстве модели
    Set boxObj = ThisDrawing.ModelSpace.AddBox(center, length, width, height)
    
    'Измените направление рассмотрения области просмотра, чтобы лучше видеть поле
    Dim NewDirection(0 To 2) As Double
    NewDirection(0) = -1: NewDirection(1) = -1: NewDirection(2) = 1
    ThisDrawing.ActiveViewport.direction = NewDirection
    ThisDrawing.ActiveViewport = ThisDrawing.ActiveViewport
    ZoomAll
    
    'Возвратите PrincipalDirections для поля
    Dim PrincipalDirections As Variant
    PrincipalDirections = boxObj.PrincipalDirections
    MsgBox "PrincipalDirections для поля " & PrincipalDirections(0) & ", " & PrincipalDirections(1) & ", " & PrincipalDirections(2), , "PrincipalDirections Пример"
        
End Sub