Page History
...
The result of each simulation step is a velocity field - i.e. the fluid simulation calculates the speed and direction of the movement of the fluid in different points in space. In order to visualize the effect, a simulation can also transport visible fields, such as smoke density, temperature, and also different kinds of particles along the velocity field that gets simulated. The two most important processes in a simulation are Advection - how the fluid moves through space, and pressure solve, called Conservation in Phoenix - which is basically the step that makes simulated fluids behave like real-world fluids - swirling, rolling and creating plumes. Both of these options are controlled from the Dynamics rollout of the Phoenix Simulators.
In order to see the effect of the A fluid simulation , a simulation can also transport visible fields , such as along the simulated velocity field. Such fields can be smoke density, temperature, and also different kinds types of particles along the velocity field that gets simulated, etc. The velocity field is the raw result of the fluid simulation and by default it's invisible, but these additional channels make the fluid motion visible. You can enable these fields for simulation from the Output rollout and then actually create them in the simulation container using Sources, or other more advanced methods.
...
Particle data is rendered by connecting a Particle Shader to the Simulator, and you can also use the Particle Shader to render standard particle systems that don't come from Phoenix. The Particle Shader is quite versatile and can draw particles as points, bubbles, or could also voxelize particles into a grid and render that as fog using the volumetric shader - this is how you can render mist from a waterfall, for example.
...
The particles can interact directly with the simulation only as sources, depending on the Emit Mode (Volume Inject or Volume Brush) of the Fire Source | PHXSource. The velocity of the injected fluid is the velocity of the particle, which allows the fluid to be involved in the particles' motion.
...
There are two direct methods that can be used to add fine details in the shading. In order to enhance the realism of the movement of small details in the fluid, V-Ray comes with a Particle Texture called Particle Texture. When used in combination with a particle system driven by a Phoenix Simulator, the particle texture is capable of properly animating the small details along the fluid surface.
...
The Phoenix solution for creating foam and splashes is particle based and is achieved by two relatively separate features - a foam/splashes particle simulator and a foam/splashes particle shader. The particle simulator is embedded in the Phoenix Simulator node and exports its content via PhoenixFDPGroup nodes, supporting position, velocity, size and id channels. The particle shader is designed as a separate component: Particle Shader. This component can render PhoenixFDPGroup and any standard particle system that exports position, size and velocity channels.
...
The birth of particles can be performed automatically (for foam and splashes) by a user source (see Fire Source) or by a script. When automatic birth is used, the simulator calculates a "birth potential" for each cell and compares this potential with the birth threshold set by the user. If the potential is above the threshold, the simulator creates new particles in the quantity specified in the "birth rate" parameter, in thousands per cubic scene unit. Both foam and splashes are born in this way; the only difference is how the "birth potential" is calculated. Additionally, when a splash particle hits the water surface, foam is automatically created.
...
| Anchor | ||||
|---|---|---|---|---|
|
...
The Particle Shader node can render the particle systems in several different ways - as separate bubbles/droplets, as points, or as fog. In fog mode, the bounding box of all particles is calculated and a grid based shader is constructed using the bounding box and the fog resolution parameter. This mode is most suitable for surface foams, when the grid height is relatively large and the particle count is huge. The other mode (particle-based shading) is more complicated and interesting; it allows us to achieve a larger variety of effects. One reasonable question about this mode is why we need it, when one can render each particle as geometry with the proper material instead. There are several advantages, but the most important one is the ability to convert the scattering into diffuse color, which gives the natural bright appearance of the foam and the splashes. Another important advantage is cellular mode, which allows shading of close-up foam.
...