Type
There are three different fluid types available:
- "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 solver and provides GPU support.
- "Liquid - PBD" is a very fast type (faster than “Liquid - SPH”) and provides GPU support.
Resolution
With this setting you can change the amount of particles. When “Resolution” is set to 1.0, a volume of 100 cm x 100 cm x 100 cm 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 combine fluids from different domains, e.g. to mimic 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.
Int Pressure
“Int Pressure” simulates the forces between nearby particles and pushes them apart - this makes the fluid fill a greater volume.
Ext Pressure
“Ext Pressure tries to limit a fluid’s expansion tendency and can be compared to atmospheric pressure.
Viscosity
Substances with very high viscosity are honey, tar or syrup, for example. Fluids with low viscosity are alcohol, many solvents or liquid gases. You can enter any positive value:
- The default value of 3.0 describes the viscosity of water.
- If the fluid does not behave correctly with higher settings (around 50+) you should consider increasing substeps under Scene > Solver.
- Equal values for "MIN | MAX Substeps" produce the best results with high viscosity. Try Liquid - PBD 20 | 20 or Liquid - SPH 200 | 200
Surface tension
A fluid's tendency to contract and create drops and tendrils is increased with higher settings. You can enter any value between 0 and 10.