1. A method comprising: spatially partitioning bodies among computational nodes, each computational node maintaining data for a different subset of the bodies; at a first node of the computational nodes, importing body data from a set of one of more spatially neighboring nodes; at the first node, computing data characterizing interactions between bodies, including: computing at least some data characterizing interactions between bodies that include at least one body for which the first node maintains data and at least one body for which data is imported from the set of spatially neighboring nodes, and computing at least some data characterizing interactions between bodies for which data is imported from the set of spatially neighboring nodes and not bodies for which the first node maintains data.