OOC - Supplementary material to your games

Have you ever added anything to the games you play? Have you created a map, an illustration, or anything that adds to the world of the game? And why did you do it? Was it for fun or was it for practical reasons, like keeping track of where the players are and have been.

Adding material like this to your games can be a good way to both add flavour to the world and to give something for the players to add to the game that really makes them feel like they are contributing and making a difference. But at the same time, you want to avoid rail-roading people in their creativity should they want to go out with the boundaries of what has been depicted. While we should be consistent in our personal and professional writing, RPs can give leeway to Rule of Cool. What if the players need there to be a river nearby but the map doesn't show it and it has never been previously mentioned, for instance? How do you balance it?

Personally, I recently sketched up a design for Blue Dwarf, of the ship the crew are currently on. While it was fun to share the design with my fellow players, I also hope it doesn't limit what they want and/or need from that ship in the future (although I'm sure it won't!).