# Can we use MCTS without a generative model?

From what I have understood reading the UCT paper Bandit based monte-carlo planning, by Levente Kocsis and Csaba Szepesvári, MCTS/UCT requires a generative model.

1. Does it mean that, in case there is no generative model of the environment, we cannot use MCTS?

2. If we can still use MCTS, how does the roll-out happen in this case, as there is no simulation?