The disclosure notably relates to a computer-implemented method for instancing a global physics simulation. The method includes obtaining a set of local simulations. The set of local simulations includes at least one local simulation. A local simulation is a physics simulation that is part of the global physics simulation and that can be computed alone and independently of the global physics simulation. Each local simulation of the set of local simulations is already computed. The method further includes, for each local simulation of the set of local simulations, computing a respective reduced model of the local simulation. The method further includes computing each global simulation of a set of at least one global simulation. Each global simulation is an instance of the global physics simulation. This constitutes an improved method for instancing a physics simulation.