Most qualitative simulation techniques perform simulation at a single level of detail highlighting a fixed set of distinctions. This can lead to intractable branching within the behavioral description. The complexity of the simulation can be reduced by eliminating uninteresting distinctions through various abstraction techniques. Behavior aggregation eliminates occurrence branching by providing a hybrid between a behavior tree representation and a history based description. Envisionment guided simulation uses an attainable envisionment graph to focus the attention of a behavior tree simulation on behaviors of interest.