Using a 512*512 node resolution with 16*16 nodes would mean too much terrain data. 512*512 resolution is only meant for very big nodes which should be used deep inside the playable area and at most 1 or 2 nodes per scene. We do not make every node 512*512 in any scene, let alone 256. We always reduce the resolution of the outer nodes. With a simple math, the weightmap and heightmap data 16x16 nodes with 512*512 resolution of 4 layers is around 4GB. Which is the internal limit of our terrain data compression utility. If you go with, lets say 8 or more layers, it becomes even more. No mod should go this high with the numbers because the players will not have that much GPU memory. If the memory is enough, the runtime performance will be bad too. A better question would be, why do you need to go that high with the layer weightmap resolutions?