Adding visual details based on low-resolution energy cascade ratios for smoke simulation

Abstract

We propose a method for adding visual details to fluid animation while reducing noisy appearances. In grid-based fluid simulations, an issue is that while highly detailed fluids with small eddies can be obtained by increasing the number of grid cells, it costs much more computational time. To address this, various methods for adding details (or up-scaling resolutions) have been proposed. Those methods can generate fine animations quickly by adding high-frequency noises or external forces to coarse simulation results. However, those methods typically generate tiny eddies on a whole surface of fluid and the result appears too noisy. In this paper, we consider the distribution of kinetic energy in the spatial frequency domain and then apply it to two existing methods for adding details. By using our method, noises or external forces can be added to the appropriate positions of fluids and consequently natural-looking details can be achieved.