I know sand and gravel generators are not allowed, but what about obsidian, cobble, and smooth stone generators?
^^ Thats true, smooth and cobble are parts of the game witch were ment to happen. Obsidian I asked about it and its allowed
To better detail: Smooth/Cobble is a natural game mechanic, so its allowed Obsidian, while its not natural, is still converting 1 item into another. It's not infinitely creating items out of thin air, so we allow it. Sand/Gravel gens however are creating items out of nothing, so its therefor duping, and not allowed.