Please bear with us a bit longer. We've fixed the client so that it now properly works with the culling and rendering systems. This has exposed some world asset problems and a bug in the world cache system. We've identified these problems and are working on fixes and re-exported world assets as quickly as we can. While accepting that this a serious but temporary problem, the benefits of the client working properly are significant for the long-term. Two suggested temporary work-arounds are re-entering the game and clearing the world-cache.
Thank you for your continued patience,
David Bowman