Animating Tree Movement with Sound Effects Generation

Abstract

This video demonstrates the methods for automatically generating tree motions and sound effects for an animation of branches and leaves moving in the wind. Natural motions of leaves and branches swaying in a wind field are created in real-time by our efficient method without using time-consuming physical simulation techniques based on the equations of motion. This method utilizes "1/f ? noise", which is observed in various natural phenomena. Specifically, in this method, the natural motions of leaves and branches are created by calculating appropriate motion angles using 1/f ? noise functions. The realism of the branch motion is enhanced by applying a real-time simple simulation technique based on the spring model. Sound effects are generated as follows: Each tree is divided into branches and leaves, and an independent sound effect generation process is employed for each element. The individual results are then compounded into one sound effect. For the branches, we employ an approach based on the frequencies of experimentally obtained Karman vortex streets. For the leaves, we use the leaf blade state as the input and assume a virtual musical instrument that uses wave tables as the sound source. All computations can be performed independently for each frame step.