Abstract

Mountain View, California 9403 In standard fractal terrain models based on fractional d Brownian motion the statistical character of the surface is, by esign, the same everywhere. A new approach to the synthesis p of fractal terrain height fields is presented which, in contrast to revious techniques, features locally independent control of the f f frequencies composing the surface, and thus local control o ractal dimension and other statistical characteristics. The new f i technique, termed noise synthesis, is intermediate in difficulty o mplementation, between simple stochastic subdivision and s n Fourier filtering or generalized stochastic subdivision, and doe ot suffer the drawbacks of creases or periodicity. Varying the w local crossover scale of fractal character or the fractal dimension ith altitude or other functions yields more realistic first approxm imations to eroded landscapes. A simple physical erosion odel is then suggested which simulates hydraulic and thermal ...

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