1. A computer-implemented method of generating a geologic model, comprising the steps of: (a) assigning a rock-property value, on a block-by-block basis, to each block of a space domain candidate geologic model having a three-dimensional array of blocks; (b) assigning, on a block-by-block basis, a local spectrum of said rock-property value to each of at least some of said blocks, each said local spectrum of said rock-property value incorporating a local spatial trend in rock property continuity for each respective block; (c) using said local spectra to frequency scale said rock-property value, on a block-by-block basis, at each of said blocks; and (d) using said scaled rock-property values to generate a scaled space domain geologic model incorporating said local spatial trend in rock property continuity.