Resolving an interaction with the AMUSE Multiples module. This diagram shows the resolution of close interactions using the Multiples module. Upper left: if two (possibly compound) objects pass close to each other (as defined by distance ) control is passed to the Multiples module (right), which transforms to center of mass coordinates and retrieves the internal structure of the particles. It calls a sub code to resolve the collision. Once this is done, the interaction products (which may not correspond to the input systems) are transformed back and returned to the main code (lower left).