SPH - Fill Object

This emitter is a true all-rounder. The emitter subdivides any object into a certain number of cells – a process that is also known as rasterization. The cells are then filled with particles representing the object’s volume. The higher the emitter’s "Resolution" parameter, the better the result, because this value directly affects the number of grid cells. That is the reason why you can see jagged lines at the fluid’s edges.

You have to be careful with double-walled objects. In this case only the space between the walls will be filled, while the innermost volume remains empty. This often leads to confusion, but is not a malfunction of the emitter. Especially with low resolution values, you can sometimes hardly see the particles filling the object. To get a better impression and simulation result, raise “Resolution” to (much) higher values.

Another important thing to know about this emitter is that the particles are regularly arranged according to the given volume. If you add a "Gravity" daemon, for example, the particles will collapse and the resulting fluid volume becomes smaller, because it is not relaxed. This effect can be compensated with higher “Int Pressure” settings.

Object

This option is essential for the making the emitter work. You can choose any object from the appearing node list, but you cannot make multi-selections – only one object per emitter is allowed. Once an appropriate selection has been made, RealFlow unlocks a few more settings.

Fill volume

By default this option is set to “No”. If you want to fill the previously selected node, simply switch to “Yes”. This action activates more parameters and simultaneously locks the “Particle layer” field.

When the particles collapse due to external forces you can observe a strong up and down movement. To get rid of this sloshing you have to simulate for a certain time to let the fluid particles settle, create an initial state and start a new simulation from this specific point. This process is called "relaxing".

fill X/Y/Z ratio

This emitter allows you to create particles along certain axes. It is possible to combine all axes using different values to achieve partial filling. A value of 0.0 means that there are no particles in a certain direction, while 1.0 entirely uses the selected axis.

remove # layers

With this function it is possible to delete particle layers from the outside to the inside. This creates a gap between the object and the fluid.

jittering

Like any other emitter, “Fill Object” uses a regular particle distribution and this leads to sometimes unwanted patterns. “jittering” adds random displacement to the particles to give a more natural look. The allowed values range between 0.0 and 1.0 for maximum randomness.

@ seed

This value is directly connected to “jittering”: whenever a random value is used, it is necessary to define an initial value and that is called “seed”. It influences the way the particles are distributed and by changing “@ seed” you can easily achieve a different look.

Particle layer

This feature is only available when “Fill volume” is set to “No”. Instead of filling a volume, “Particle layer” regularly spreads particles over the node’s surface. The look is actually exactly the same as with the object emitter, but “Particle layer” does not create a constant particle stream.