1. A computer implemented method for deriving reverberation characteristics for a computer-generated environment from graphics data that are used by a computing system having a processor and reverberation engine for visually displaying contents of the computer-generated environment, comprising the computing system performing steps of: (a) selecting a position of interest in the computer-generated environment; (b) accessing the graphics data that are used for displaying at least a portion of the computer-generated environment viewable from the position of interest when the computer-generated environment is rendered; and (c) automatically deriving reverberation characteristics for the position of interest from the graphics data for each of a plurality of points in the portion of the computer-generated environment, the reverberation characteristics being derived at least in part from: (i) a distance of the point from the position of interest; and (ii) a hardness value associated with the point, the hardness value indicating a relative level of acoustic reflectance that is associated with the point˜wherein the reverberation characteristics include a plurality of environmental parameters from which the property set values are calculable when the computer-generated environment is rendered, and wherein the environmental parameters for the points include at least two of: a mean distance to the points from the position of interest; a mode distance to the points from the position of interest; a median distance to the points from the position of interest; a mean hardness value associated with the points; and a total number of points in the portion of the computer-generated environment.