not just a grid, but just start your own server-clientside system. i think you’ve come to terms with how your enduser for mainstream virtual worlds will always be using graphics cards 5+ years out of date – they can’t locally render the shadows and other coolness. so, solution: server-side render. client-side “navigation” (pan, zoom, walk data sent to server for render), but instead of local rendering, receives just a video feed of realtime rendering from serverside. This also makes for 3d interactive virtual worlds for mobile devices, as most nowadays can easily handle HD video!