http://ericwilhelm.homeip.net/uber-converter/doc/hub_is_a_node/ Hopefully, this helps to focus the design and clarify our discussions. The current goal is to create the rhizopod hub. Everything else comes later. That said, my suggestion is that the drawing entity contain a format name and version number. A connector would never be expected to operate on a hub with more than one format (e.g. a rhizopod connector cannot load sturgeon drawings), though it should be possible to load multiple versions of the hub format. Given that rhizopod is rhizopod, we should not be overly concerned about huge and incompatible changes within a hub format. Once the rhizopod spec reaches version 1.0, it should basically be done. --Eric -- "Politics is not a bad profession. If you succeed there are many rewards, if you disgrace yourself you can always write a book." --Ronald Reagan