Hi @flewis,
sorry, there has been some mix-up with access rights, you should be now able to access the page. About your fix: It does not really matter if you do it manually or not. While you can decouple the modification of the node attributes - which is allowed from within a thread - from the redraw event, to carry out that newly computed camera transform, you still will have to invoke a redraw, which you cannot do from within your threaded environment. When you invoke such redraw event, the first thing the internal code does, is to check if its running on the main thread and if not, it just gets out. So there is not much won by doing it manually, at least for what from my understanding is the premise of your problem: To constantly frame the viewport to the object that is currently processed by your async code.
Cheers,
Ferdinand