Specifies the direction of the major axis of the ellipse.
Supported platforms: Windows only
Read-only: No
Type: Variant (three-element array of doubles)
A 3D vector defining the major axis. The vector originates at the ellipse center.
The longer axis of an ellipse is called the major axis; the shorter one is the minor axis.

VBA:
Sub Example_MajorAxis()
' This example creates an ellipse and finds the major axis
' for that ellipse. It then changes the major axis for the ellipse.
Dim ellObj As AcadEllipse
Dim majAxis(0 To 2) As Double
Dim center(0 To 2) As Double
Dim radRatio As Double
' Create an ellipse in model space
center(0) = 5#: center(1) = 5#: center(2) = 0#
majAxis(0) = 10: majAxis(1) = 20#: majAxis(2) = 0#
radRatio = 0.3
Set ellObj = ThisDrawing.ModelSpace.AddEllipse(center, majAxis, radRatio)
ellObj.Update
MsgBox "The ellipse has a major axis of " & majAxis(0) & ", " & majAxis(1) & ", " & majAxis(2), vbInformation, "MajorAxis Example"
' Change the major axis of the ellipse
majAxis(0) = 5: majAxis(1) = 5: majAxis(2) = 0
ellObj.MajorAxis = majAxis
ellObj.Update
' Query the major axis of an Ellipse
Dim retMajAxis As Variant
retMajAxis = ellObj.MajorAxis
MsgBox "The ellipse has been udpated with the major axis " & retMajAxis(0) & ", " & retMajAxis(1) & ", " & retMajAxis(2), vbInformation, "MajorAxis Example"
End Sub
Visual LISP:
(vl-load-com)
(defun c:Example_MajorAxis()
;; This example creates an ellipse and finds the major axis
;; for that ellipse. It then changes the major axis for the ellipse.
(setq acadObj (vlax-get-acad-object))
(setq doc (vla-get-ActiveDocument acadObj))
;; Create an ellipse in model space
(setq center (vlax-3d-point 5 5 0)
majAxis (vlax-3d-point 10 20 0)
radRatio 0.3)
(setq modelSpace (vla-get-ModelSpace doc))
(setq ellObj (vla-AddEllipse modelSpace center majAxis radRatio))
(vla-ZoomAll acadObj)
(vla-Update ellObj)
(setq majAxis (vlax-variant-value majAxis))
(alert (strcat "The ellipse has a major axis of " (rtos (vlax-safearray-get-element majAxis 0) 2) ", "
(rtos (vlax-safearray-get-element majAxis 1) 2) ", "
(rtos (vlax-safearray-get-element majAxis 2) 2)))
;; Change the major axis of the ellipse
(setq majAxis (vlax-3d-point 5 5 0))
(vla-put-MajorAxis ellObj majAxis)
(vla-Update ellObj)
;; Query the major axis of an Ellipse
(setq retMajAxis (vlax-variant-value (vla-get-MajorAxis ellObj)))
(alert (strcat "The ellipse has been udpated with the major axis " (rtos (vlax-safearray-get-element retMajAxis 0) 2) ", "
(rtos (vlax-safearray-get-element retMajAxis 1) 2) ", "
(rtos (vlax-safearray-get-element retMajAxis 2) 2)))
)