Alias and the API have slightly different definitions of curve and surface form. After building a Closed curve or surface in Alias where the first and last CV’s are co-incident, the information window will still report that the curve or surface is Open. This is because Alias does not support the concept of Closed geometry. The API supports Closed geometry and AlCurve::form() and AlSurface::vForm() or uForm() will report that the curve or surface is Closed.