DyDomain - Particles: Liquid - SPH

The Dyverso domain holds the particles, while the emitter nodes represent the point of emission.

 

 

Type

There are eight different types of fluids and materials. All types, except "Dumb", are → GPU-accelerated:

  • "Dumb” particles are often used for spray or foam. These particles cannot react with each other and do not have the characteristic fluid properties, but they are simulated very fast.
  • "Liquid - SPH" is a very accurate fluid solver.
  • "Liquid - PBD" is a very fast fluid type (faster than “Liquid - SPH”).
  • "Granular" is suitable for substances like sand or snow.
  • "Viscous" fluids are suited for substances like lava, toothpaste, caramel, syrup, or mud.
  • "Viscoelastic" is the choice of materials such as rubber, caoutchouc, silicone, or "memory foam".
  • "Rigid" connects the particles with more or less rigid joints. This particle type requires at least one object instead of an emitter and you have to follow a specific → workflow.
  • "Elastic" lets you simulate jelly-like substances. This particle type requires at least one object instead of an emitter  and you have to follow a specific → workflow.

Different materials are partially able to interact: SPH + SPH + Granular (+ Rigid with limitations), PBD + PBD + Granular (+ Rigid with limitations).

Resolution

With this setting you can change the amount of particles, “Resolution” mainly depends on scene scale and emitter scale, but it also affects the fluid’s mass and therefore depends on “Density”, too:

  • With “Resolution” set to 1.0, a volume of 1 m x 1 m x 1 m filled with 1,000 particles.
  • The parameter accepts any positive value.
Density

This parameter is defined as mass per volume unit and is different for each substance. “Density” does not change the fluid's behaviour, but it is possible to mix fluids from different domains. This way you are able to simulate substances like oil and water. The unit is kilograms per cubic metre. The density of water is 1,000 kg/m3. Avoid very small values close to 0, because they can lead to instabilities.

Internal pressure

“Internal Pressure” simulates the forces between nearby particles and pushes them apart - this makes the fluid fill a greater volume.

External pressure

“External Pressure" tries to limit a fluid’s expansion tendency and can be compared to atmospheric pressure. Particles tend to "stick" together with higher values.

The substeps and iterations settings in RealFlow's → "Simulation Options" influence how this parameter acts on the fluid.

Viscosity

Substances with very high viscosity are honey, tar or syrup, for example. Fluids with low viscosity are alcohol, many solvents or liquid gases. The default value of 3.0 describes the viscosity of water. You can enter any positive value.

Surface tension

A fluid's tendency to contract and create drops and tendrils is increased with higher settings. You can enter any positive value. The substeps and iterations settings in RealFlow's → "Simulation Options" influence how this parameter acts on the fluid.

Vorticity boost

To get a more turbulent and water-like fluid, increase this factor, but try to avoid very high values (unless necessary), because they can completely distort the fluid. In many cases, values between 1.0 and 50.0 produce good results.

Max particles

Please enter a value to stop emission at a certain amount of particles. "Max particles" is based on the total amount of emitted particles. Let's say you have entered "50,000". If there are currently 1,000 particles in your scene, but you have already deleted 49,000 particles RealFlow will stop the emission. Here you can read how to use this parameter to → stop particle emission.

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