Combining multiple flow fields for editing existing fluid animations

In this paper, we develop a method for synthesizing desired flow fields by combining existing multiple flow fields. Our system allows the user to specify arbitrary regions of the precomputed flow fields and combine them to synthesize a new flow field. In order to maintain plausible physical behavior, we ensure the incompressibility for the combined flow field. To address this, we use stream functions for representing the flow fields. However, there exist discontinuities at the boundaries between the combined flow fields, resulting in unnatural animation of fluids. In order to remove the discontinuities, we apply Poisson image editing to the stream functions.