Domain - Particle Sampling

The parameters of this panel provide an easy-to-use method to control the number of particles per grid cell – even individually in the areas between the fluid and interacting objects. Maybe you have come across the Hybrido emitter node's particle sampling already, and ask yourself what the difference is between both options. With the domain's method, the number of particles is controlled in every simulation step. Whereas the Hybrido emitter's sampling creates the according number of particles at the beginning of the simulation only.

Please bear in mind that the freshly created particles currently do not inherit properties from their surrounding particles. This can be problematic in terms of the creation of UV coordinates, because the new particles might falsify the results. We therefore recommend disabling the domain's particle sampling if you want to extract UVs from the core fluid.

Min sampling control

When enabled, you will be able to control the minimum number of particles per cell with the associated parameter.

@ min sampling

This value represents the minimum number of particles per cell. When the number of particles is smaller than given here Hybrido will add new particles. Please bear in mind that it is not always possible to reach the given value exactly, because the new particles should not change the fluid's dynamics. This is mainly the case in areas between the fluid and the surrounding air, but also between the fluid and objects.

Max sampling control

The mode of operation is exactly the same as with “Min sampling control”. When set it to “Yes” you will be able to control the maximum number of particles per cell.

@ max sampling

In cells with more particles than given here, particles will be removed. It is important to understand that this limit is not always reached to maintain the fluid's dynamics. This is mainly the case in areas between the fluid and the surrounding air, but also between the fluid and objects.

Min sampling object boundaries control

This parameter is interesting for fluid-object interactions, because it addresses the problem of isolated, empty cells between the fluid and an object's boundaries, These cells are responsible for a temporary increase in the fluid's speed, resulting in a flash-like effect that can be seen when the particles' velocity channel is active in the “Display” panel. In many cases, this behaviour can be observed when a container is used to enclose the fluid.

@ min sampling object boundaries

Enter a value to define the minimum number of particles per cell in the transition between the fluid and an object.

Max sampling object boundaries control

When this parameter is set to “Yes” you will be able to control the maximum number of particles per cell in areas between the fluid and an object. Its main purpose is to reduce unwanted velocity changes which sometimes occur in areas when the fluid interacts with an object.

@ max sampling object boundaries

Here, it is possible to set a maximum particle limit in the areas between the fluid and interacting objects.