Large scale agent-based simulations typically face a trade-off between the level of detail in the representation of each agent and the scalability seen as the number of agents that can be simulated with the computing resources available. In this paper, we aim at bypassing this trade-off by considering that the level of detail is itself a parameter that can be adapted automatically and dynamically during the simulation, taking into account elements such as user focus, or specific events. We introduce a framework for such a methodology, and detail its deployment within an existing simulator dedicated to the simulation of urban infrastructures. We evaluate the approach experimentally along two criteria: (1) the impact of our methodology on the resources (CPU use), and (2) an estimate of the dissimilarity between the two modes of simulation, i.e. with and without applying our methodology. Initial experiments show that a major gain in CPU time can be obtained for a very limited loss of consistency.