Frequency-domain smoke guiding

We propose a simple and efficient method for guiding an Eulerian smoke simulation to match the behavior of a specified velocity field, such as a low-resolution animation of the same scene, while preserving the rich, turbulent details arising in the simulated fluid. Our method works by simply combining the high-frequency component of the simulated fluid velocity with the low-frequency component of the input guiding field. We show how to eliminate the grid-aligned artifacts that appear in naive guiding approaches, and provide a frequency-domain analysis that motivates the use of ideal low-pass and high-pass filters to prevent artificial dissipation of small-scale details. We demonstrate our method on many scenes including those with static and moving obstacles, and show that it produces high-quality results with very little computational overhead.