GPU Pro 5

60 I Rendering

4.6 Particle Update

We update the position and velocity of particles following the Particle-In-Cell

(PIC) and Fluid-In-Particle (FLIP) approaches that mix particles and grids [Zhu

and Bridson 05]. The main idea with these numerical schemes is that instead of

sampling the grid to assign new values (e.g., velocities) to the particles, we can

recover only the differences to their original values.

4.6.1 Particle Velocity

In PIC, the particle’s velocity is taken directly from the grid, which tends to

be very dissipative, viscous and leads to damped flow. For more lively features

and better energy conservation, FLIP assigns only the difference