u/BrowniesVsBagels

Does anyone know of a game feature or a mod that would let me paint lines and color tiles on the map, for purely design reasons? I know I can lay stone surfaces and paint on those, but that costs materials and time. I want to be able to shade an area and earmark it for some later purpose. Like sketch out where a refinery or mfg area, or roads, would be. A purely visual thing with no effect on the gameplay. Thanks!