Keyframe Control of Complex Particle Systems Using the Adjoint Method
Control of physical simulation has become a popular topic in the field of computer graphics. Keyframe control has
been applied to simulations of rigid bodies, smoke, liquid, flocks, and finite element-based elastic bodies. In this
paper, we create a framework for controlling systems of interacting particles -- paying special attention to simulations
of cloth and flocking behavior. We introduce a novel integrator-swapping approximation in order to apply
the adjoint method to linearized implicit schemes appropriate for cloth simulation. This allows the control of cloth
while avoiding computationally infeasible derivative calculations. Meanwhile, flocking control using the adjoint
method is significantly more efficient than currently-used methods for constraining group behaviors, allowing the
controlled simulation of greater numbers of agents in fewer optimization iterations.
C. Wojtan, P. J. Mucha, and G. Turk, Keyframe Control of Complex Particle Systems Using the Adjoint Method. ACM SIGGRAPH/Eurographics Symposium on Computer Animation, 15-23 (2006).