Tiles imported into the Import Heightmap dialog, and the Tiles section, report: TerrainToolbox: Imported heightmap resolution is not power of two. UnityEngine.GUIUtilityrocessEvent(Int32, IntPtr) Well, it is actually. The menu options are not powers of two, they are powers of two plus one. I have tried tiles that are 2048 and 2049, but it throws this error every time. This on a 10km x 10km terrain. Or would be if it worked.