Volumetric Fluid, Smoke, and Fire - Mastering Blender - page 449

There are two distinct ways to use the particles, although they are not entirely independent of each other.
One use of particles is to enhance the appearance of the fluid sim meshes themselves. In this case, the particles
are usedtocontribute actual geometry tothe mesh, which can result inthe appearance ofhigher-resolution sim-
ulations and greatly increase the “splashiness” of the simulation. The other option is to use the same particles
in a more traditional way, to add a halo-based haze to the fluid that follows the fluid's movement in a sensible
way. This can be particularly good for simulating foam and spray from rushing water and can be useful when
faking larger-scale fluid effects. Furthermore, there are three distinct types of particle systems created by the
fluid simulator that are used in slightly different ways, as you will see in the next section.
Particle Splash
To see a good example of how particles can be used to get splashier fluids, set up a fluid simulation with an
inflow along the lines of the example shown earlier in Figure 7-16 .
The relevant fields for adding a particle-based effect can be found in the Domain Particles panel in the Phys-
ics properties area of the Domain object. The degree of splashiness (and the number of particles) is determined
by the value in the Generate Particles field. The default value of 0 means no particles are generated. A value
of 1.00 means a “normal” number of particles are generated, and a value of greater than 1 means more than a
normalnumberaregenerated.Thedegreeofsplashinessthatyouactuallyseeasaresultoftheparticlesdepends
also on the force with which the fluid strikes an obstacle or wall. This, in turn, depends on the initial velocity of
the fluid and on the impact factor of the obstacle, which I talk about in the next section.
In order for the particles to affect the mesh geometry, it is also necessary to set the Surface Subdivisions on
the Domain Boundary panel to a value greater than 1. The values should be set as shown in Figure 7-22 .