I've been creating terrain materials by modifying json files, but they don't always show up in the game. After checking all the commas, file paths, file extensions, and other errors I typically find (or make), I'm stumped on certain materials. I've added the material names to the terrain.json file. To create a persistentId that's unique within the level, I often change one character in the ID value. It's a very long string, so changing one random character should result in a unique value. But it led me to wonder whether it has to be unique within the level, or within the whole game. If it's just the level, I'm considering writing a json from scratch, using sequential values with the correct ID string length. Has anyone had success creating terrain material files from scratch?