: Ellipse traveling through a shallow pool of water (left), formation of a milk crown (center), smoke rising past a sphere (right). We present a method for simulating water and smoke on an unrestricted octree data structure exploiting mesh refinement techniques to capture the small scale visual detail. We propose a new technique for discretizing the Poisson equation on this octree grid. The resulting linear system is symmetric positive definite enabling the use of fast solution methods such as preconditioned conjugate gradients, whereas the standard approximation to the Poisson equation on an octree grid results in a non-symmetric linear system which is more computationally challenging to invert. The semi-Lagrangian characteristic tracing technique is used to advect the velocity, smoke density, and even the level set making implementation on an octree straightforward. In the case of smoke, we have multiple refinement criteria including object boundaries, optical depth, and vorticity concentration. In the case of water, we refine near the interface as determined by the zero isocontour of the level set function.
Losasso et al. REF presented a method for simulating water and smoke with an octree data structure, exploiting mesh refinement techniques to capture small-scale visual details.
Simulating water and smoke with an octree data structure
SIGGRAPH '04
Computer Science