1. A method for creating an acoustic model of a structure based on a finite-element model of the structure, the method being performed by computer-executable instructions stored on a computer readable storage media that, when executed on a processor, perform a method comprising: retrieving a finite-element model having a plurality of elements with each element having a centroid; determining at least one composite centroid based on a first set of two or more first elements, the composite centroid having a spatial position and weight, the composite centroid being stored on the computer readable storage media; determining a cross-spectral correlation function of the structure based on the composite centroid; and predicting a reaction of the structure to acoustic stimuli using the cross-spectral correlation function as the acoustic model of the structure.