DyDomain - Particles: Viscoelastic

Owned by thomas (Unlicensed)
Last updated: 31 Jan, 2018
3 min read

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, caramel, syrup, or mud.
  • "Viscoelastic" is the choice of materials such as ketchup, toothpaste, or 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.

Not all materials are able to interact. For a complete list of possible interactions please visit this page (see "Particle and Material Types").

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 scale

This parameter 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.

Tensile strength

Higher settings increase a fluid's tendency to contract and form string-like structures. As a side-effect, the fluid's borders become thicker. "Tensile strength" accepts any positive value, but should not be greater than 1.

Viscosity

This parameter lets you create substances like cream, chocolate, oil, honey, or tooth paste:

  • “Viscosity” ranges between 0 and 1 and can be animated.
  • To get a more rigid behaviour increase the solver's → substeps (10/10 is a good start) and → iterations.
Cohesion

"Cohesion" is a force of attraction between nearby particles. "Cohesion" is a force of attraction between nearby particles. With particle streams you will get a look similar to toothpaste or thick paint coming out of a tube. Any value ≥ 0 is accepted. The substeps and iterations settings in RealFlow's → "Simulation Options" influence how this parameter acts on the particles.

Elasticity

The higher the value, the more "wobbling" effects and stronger bounces you will observe. It is possible counteract these bounces with “Damping”. The parameter accepts any input ≥ 0, but values greater than 1,000 normally do not make the material more elastic.

Damping

Damping smoothens the relative velocities between nearby particles. A small amount of damping helps to stabilize a simulation, while higher values introduce (more) viscosity to the material.

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.