HySPH - Particles (Liquid - Hybrido)

When this particle type is used the splash particles are no longer controlled by RealFlow's HySPH solver for secondary elements, but obey our grid-based HyFLIP method. For this reason, you will not find any particle-fluid related parameters, for example “Density” or “Viscosity”, but a “Cell size” value. “Liquid – Hybrido” particles also behave like fluid and share the same thresholds to trigger their emission. The difference is that the particles are not controlled by the HySPH solver for secondary particles, but the Hybrido grid solver (HyFLIP).

Type

If you do not want to use the default “Dumb” type you can also switch to “Liquid - Particles” or "Liquid - Hybrido". Simulations with "Liquid - Particles" take much longer, but they also create very realistic results, especially for mid-scale simulations. Other types, like “Elastics” or “Gas” are not available with HySPH emitters. With "Liquid - Hybrido" the particles will be controlled by RealFlow's Hybrido solver.

Cell size

The area in which the particles are created is subdivided into cells. Small values increase the number of cells and create more detail, but also take longer to simulate. Higher values are often used for previews, distant fluids or very large scenes. The number of cells is also responsible for the number of particles, because each volume element contains a certain number of particles.

The value given here is directly connected to the project's scene scale settings. With RealFlow's standard scale of 1.0, one square of the viewport's grid measures exactly 1.0 m x 1.0 m. With the parameter's default value of 0.3, the smallest volume element of the domain is 0.3 m x 0.3 x 0.3 m. A value of 0.01 represents a voxel size of 0.01 m x 0.01 m x 0.01 m – that is just 1 cm per side. With such a tiny voxel size, the number of particles can easily reach several millions – depending on the size of the emitter. "Cell size" is measured in metres [m].

When you work with “Cell size” and objects you also have to take the object's “Volume” panel into consideration. There you will find another “Cell size” value, but this time for the rasterization of the colliding/interacting object. The associated Hybrido domain provides a “Cell size” value as well. By default, all these different size parameters share the same value.

Max particles

This parameter provides a very convenient method of controlling the number of particles, although it is rarely used. When the total number of emitted particles exceeds this value, the emitter will not be able to create more particles and emission stops.