The element created by this method is not inserted into the model. Use the GmlObject's @gml:TransObject!insertElement method to insert the new element into a parent object. Or, use the GmlObject's @gml:TransObject!createElement method to create an element and insert it into a parent object in a single step.
TIP: Prefer using this method to create composite elements. When creating a composite element, it is more efficient to create the element and its sub-elements off the model, before inserting the composite element to the model.