From OpenSCADAWiki
Any dynamic system object is inherited from "TCntrNode" object, which contains a mechanism to connect via the "AutoHD" template. The main function of the template is to store the link to the object and the capture of the resource, excluding the deleting of the object at the time of use. Template supports copying the resource and its release in case of destruction of the template object. For clarity of the access to the objects generated by "TCntrNode" the "AutoHD" template supports casting, based on the dynamic cast.