Context. In computer graphics, realistic looking fluid is often desired. Simulating realistic fluids is a time consuming and computationally expensive task, therefore, much research has been devoted to reducing the simulation time while maintaining the realism. Two of the more recent optimization algorithms within particle based simulations are two-scale simulation and regional time stepping (RTS). Both of them are based on the predictive-corrective incompressible smoothed particle hydrodynamics (PCISPH) algorithm.

Objectives. These algorithms improve on two separate aspects of PCISPH, two-scale simulation reduces the number of particles and RTS focuses computational power on regions of the fluid where it is most needed. In this paper we have developed and investigated the performance of an algorithm combining them, utilizing both optimizations.

Methods. We implemented both of the base algorithms, as well as PCISPH, before combining them. Therefore we had equal conditions for all algorithms when we performed our experiments, which consisted of measuring the time it took to run each algorithm in three different scene configurations.

Results. Results showed that our combined algorithm on average was faster than the other three algorithms. However, our implementation of two-scale simulation gave results inconsistent with the original paper, showing a slower time than even PCISPH. This invalidates the results for our combined algorithm since it utilizes the same implementation.

Conclusions. We see that our combined algorithm has potential to speed up fluid simulations, but since the two-scale implementation was incorrect, our results are inconclusive.