Remove Air Bubbles

– This checkbox (which is checked by default), helps to avoid any space between the fluid and an obstacle.
– The result depends from the mesh of the obstacle and from the domain resolution.

– As you can see in this example, not all ‘air bubbles’ are removed, producing a little weird simulation also when this option os checked (actually I used an opaque material for the fluid Domain to help to understand what this parameter does and a low domain resolution but as usual my goal is not to render realistic simulations!).

Blender Fluid Remove Air Bubbles

Tracer

– The Lattice Boltzmann Method (LBM) used by Blender to simulate the evolution of a fluid stores average values over each cell (Voxel).
– Tracer particles are to track the evolution of the fluid using discrete particles in well-defined positions and independent of the dimension of the Voxels.
– Unfortunately at this moment tracer particles are not always behaving nice, some stick to the walls of the domain and seem to be dead. I hope blender developers fix this soon!
– To create tracer particle add another object with the Particle Fluid type, that uses the same bake directory as the Domain.

– In this example you can see how tracer particles follow the motion of the fluid. You can also see lot of particles sticked to the left side of the domain (Domain Boundary Type was set as Free-Slip so no particle should stick to it!).

Blender Fluid Tracer

Drops

– You need three Objects:

– A Fluid object Type: Domain
– A Fluid object Type: Fluid (inside the Domain)
– A Fluid object Type: Particle (no matter where)

– Set the same cache directory for the ‘Fluid: Domain’ object and the ‘Fluid: Particle’ object
– Check ‘Drops’ from the Settings tab of the ‘Fluid: Particle’ object
– Bake!

– In this example the Drops particles are coloured in light blue
– Note how the presence of Drops particles is not only a visual effects but also affects the simulation (as you can see from the poster image).

– And if you are curious to see how a video looks with the only drops rendered, here it is!

Blender Fluid Particle Drops

Floats

– You need three Objects:

– A Fluid object Type: Domain
– A Fluid object Type: Fluid (inside the Domain)
– A Fluid object Type: Particle (no matter where)

– Set the same cache directory for the ‘Fluid: Domain’ object and the ‘Fluid: Particle’ object
– Check ‘Floats’ from the Settings tab of the ‘Fluid: Particle’ object
– Bake!

– In this example the Floats particles are coloured in light blue
– Note how the presence of Floats particles is not only a visual effects but also affects the simulation (as you can see from the poster image).

– In this example I rendered (video on the right) only the Floats particles:

Blender Fluid Particle Floats

Impact Factor

– Amount of fluid volume correction for gain/loss from impacting with moving objects.
– If the obobstacle is not moving, this setting has no effect.
– Values smaller than 1 take volume of Fluid away from the Domain.
– Values greater than 1 add volume of Fluid to the Domain.

– In this example the container was set as an Obstacle, see how the volume of the fluid changes while the Obstalce is moving:

Blender Fluid Impact Factor

Export Animated Mesh

– Enable this option if the mesh is deformed by an Armature (as in this example), Shape Keys or Lattice.
– Is not required if the mesh is animated with position or rotation Ipos (Loc,Rot).
– Note that this can be significantly slower.
– Remember: these videos don’t pretend to be realistic, the only pourpose is to show how the parameters work!

– In this example note how the object fluid set as Obstacle (and deformed by an Armature) interacts with the fluid only when the Export Animated Mesh checkbox is selected:

Blender Fluid Export Animated Mesh