Determines if the specified curve is closed (that is, the start point is the same as the endpoint)
(vlax-curve-isClosed curve-obj)
T if the curve is closed; otherwise nil.
Determine if the ellipse used to demonstrate vlax-curve-getArea is closed:
_$ (vlax-curve-isClosed ellipseObj)
T
Determine if the spline used to demonstrate vlax-curve-getDistAtParam is closed:
_$ (vlax-curve-isClosed splineObj)
nil