Interactive Localized Liquid Motion Editing

This video is from the SIGGRAPH Asia 2013 paper entiled "Interactive Localized Liquid Motion Editing" by Zherong Pan, Jin Huang, Yiying Tong, Changxi Zheng and Hujun Bao Abstract: Animation techniques for controlling liquid simulation are challenging: they commonly require carefully setting initial and boundary conditions or performing a costly numerical optimization scheme against user-provided keyframes or animation sequences. Either way, the whole process is laborious and computationally expensive. We introduce a novel method to provide intuitive and interactive control of liquid simulation. Our method enables a user to locally edit selected keyframes and automatically propagates the editing in a nearby temporal region using geometric deformation. We formulate our local editing techniques as a small-scale nonlinear optimization problem which can be solved interactively. With this uniformed formulation, we propose three editing metaphors, including (i) sketching local fluid features using a few user strokes, (ii) dragging a local fluid region, and (iii) controlling a local shape with a small mesh patch. Finally, we use the edited liquid animation to guide an offline high-resolution simulation to recover more surface details. We demonstrate the intuitiveness and efficacy of our method in various practical scenarios.