Stephen Chenney

Learn More
We present <i>flow tiles</i>, a novel technique for representing and designing velocity fields. Unlike existing procedural flow generators, tiling offers a natural user interface for field design. Tilings can be constructed to meet a wide variety of external and internal boundary conditions, making them suitable for inclusion in larger environments.(More)
Crowd simulation for virtual environments offers many challenges centered on the trade-offs between rich behavior, control and computational cost. In this paper we present a new approach to controlling the behavior of agents in a crowd. Our method is scalable in the sense that increasingly complex crowd behaviors can be created without a corresponding(More)
Traditional collision intensive multi-body simulations are difficult to control due to extreme sensitivity to initial conditions or model parameters. Furthermore, there may be multiple ways to achieve any one goal, and it may be difficult to codify a user's preferences before they have seen the available solutions. In this paper we extend simulation models(More)
We describe a technique for generating cartoon style animations of smoke. Our method takes the output of a physically-based simulator and uses it to drive particles that are rendered using a variant of the depth differences technique (originally used for rendering trees). Specific issues we address include the placement and evolution of primitives in the(More)
Group behaviors are widely used in animation, yet it is difficult to impose hard constraints on their behavior. We describe a new technique for the generation of constrained group animations that improves on existing approaches in two ways: the agents in our simulations meet exact constraints at specific times, and our simulations retain the global(More)
We introduce Group Motion Graphs, a data-driven animation technique for groups of discrete agents, such as flocks, herds, or small crowds. Group Motion Graphs are conceptually similar to motion graphs constructed from motion-capture data, but have some important differences: we assume simulated motion; transition nodes are found by clustering group(More)
Culling of Dynamic Systems in Virtual Environments Stephen Chenney David Forsyth* University of California at Berkeley Scalable rendering of virtual environments requires culling objects that have no etTect on the view. This paper explores culling moving objects by not solving the equations of motion of objects that don’t tiect the view. While this approach(More)
Using dynamical systems rather than keyframing to animate a world is a desirable yet computationally expensive approach. We present techniques for culling dynamical systems that avoid unnecessary computation, and describe tools for automating much of the required work. Based on qualitative observations of how viewer’s predict dynamical state over time, we(More)
The generation of realistic motion satisfying user-defined requirements is one of the most important goals of computer animation. Our aim in this paper is the synthesis of realistic, controllable motion for lightweight natural objects in a gaseous medium. We formulate this problem as a large-scale spacetime optimization with user controls and fluid motion(More)