The IDLgrModel::Add procedure method adds a child to this Model.
Obj->[IDLgrModel::]Add, Object [, /ALIAS] [, POSITION=index]
An instance of an atomic graphic object or another model object to be added to the model object.
Set this keyword to a nonzero value to indicate that an alias-rather than the object itself-is to be added to the model. With this keyword you can add the same object to multiple models without duplicating that object and its children. If this keyword is set, the PARENT keyword on the object being added will not change. Furthermore, if this keyword is set, the object being added will not be destroyed when the model is destroyed.
Set this keyword equal to the zero-based index of the position within the container at which the new object should be placed.