From some experimentation I find that the only way to make a Viewable get a meaningful perspective argument when executing view_* methods is to make sure that the references to that Viewable are given to clients as return values from perspective_* methods called on a pb.Avatar.
In particular, if the Avatar gives a client a reference to a Viewable by passing it as an argument to a remote_* method on the client, subsequent invocations of view_* methods by the client result in perspective argument in view_* methods being None. I have attached a complete working example of a client and server that succinctly illustrates this issue. Question: Is there a way to distribute un-asked for references to Viewables that properly get the perspective argument in their view_* methods? Sincerely, Daniel Sank