A method for cartoonstyle rendering of liquid animations.pdfVIP

A Method for Cartoon-Style Rendering of Liquid Animations Ashley M. Eden UC Berkeley eden@ Adam W. Bargteil CMU adamwb@ Tolga G. Goktekin UC Berkeley goktekin@ Sarah Beth Eisinger UC Berkeley seisinger@ James F. O’Brien UC Berkeley job@ Figure 1: This sequence of water sloshing back and forth in an invisible tank demonstrates our cartoon rendering style for liquid animations. The sequence begins when the fluid is released from a cuboid shape, sloshes against the opposite wall, back against the first wall, and eventually settles on the ground. ABSTRACT In this paper we present a visually compelling and informative car- toon rendering style for liquid animations. Our style is inspired by animations such as Futurama,1 The Little Mermaid,2 and Bambi2. We take as input a liquid surface obtained from a three-dimensional physically based liquid simulation system and output animations that evoke a cartoon style and convey liquid movement. Our method is based on four cues that emphasize properties of the liquid’s shape and motion. We use bold outlines to emphasize depth discontinu- ities, patches of constant color to highlight near-silhouettes and ar- eas of thinness, and, optionally place temporally coherent oriented textures on the liquid surface to help convey motion. CR Categories: I.3.7 [Computer Graphics]: Three-Dimensional Graphics and Realism—Animation; Keywords: Non-photorealistic rendering, image processing, natu- ral phenomena, surface tracking, semi-Lagrangian contouring. 1 INTRODUCTION Although liquids have long been portrayed in traditional artwork and animation, there are no techniques designed specifically for the cartoon-style rendering of three-dimensional liquid animations. However, non-photorealistic rendering techniques do exist for the animation of other fluids. For example, Selle et al. [32] present a method for cartoon rendering of smoke animations. Because these methods are for rendering particle-based fluid flow, they are not well-suited to free-sur