A density-accurate tracking solution for smoke upresolution

Controlling smoke simulations is a notoriously challenging and tedious task, usually requiring many trial-and-error iterations that prevent using expensive computations at high resolutions. Unfortunately, naïvely going from a more efficient low-resolution simulation to a high-quality high-resolution simulation usually results in a different behavior of smoke animation. Moreover, the longer the animation, the more different the result. We propose a tracking procedure where we optimally modify the velocity field of the simulation in order to make the smoke density distribution closely follow the low-resolution density in both space and time. We demonstrate the benefits of our approach by accurately tracking various 2D and 3D simulations. The resulting animations are predictable, preserving the coarse density distribution of the low-resolution guides, while being enhanced with plausible high-frequency details.