hawkeyefan
Legend
Established by the GM in their campaign notes, I would gather. Not every GM treats the world like a shapeless mass of potential until the PCs interact with it.
Edit: that came off as harsh, I'm sorry. It's a different way to play that plenty of people enjoy.
No worries. I was asking just to make sure there wasn’t more to it beyond that kind of play. I took @Fenris-77 ’s point to be that there must always be some element of “shapeless mass of potential” most of the time. The degree may vary, for sure, but no matter how detailed before hand, prep can only do so much. Hence his suggestion that @Lanefan add some qualifiers to his idea about illusionism and metagaming by the GM.
The idea presupposes that kind of approach, but even within that approach, the GM has to change things on the fly.