Liquid Dynamics

Expand – Opens a floating dialog that contains the selected rollout and automatically folds the command panel rollout.

Re-Center – Resets the position of the floating rollout.

? – Opens up the help documents for the Liquid Dynamics.

Simulate Air Effects | simair – When enabled, turns on the built-in air simulator for the areas in the simulation grid which are not full of liquid. The air velocity can be affected by the liquid movement, by Sources, or by fast moving obstacles inside the Simulator. In turn, the air velocity will affect and carry splash, mist, and foam particles. Note, however, that no matter how strong the air velocity is, it will not affect the liquid back. So for example you can use Simulate Air Effects when realistic mist is needed in waterfall setups, or stormy ocean scenes. The air simulation can dramatically increase the quality of splash and mist effects.

Motion Inertia | ext_wind – When enabled, moving the Simulator's object over a series of frames causes inertial forces in the opposite direction of the movement. This allows you to link the Simulator to a moving object and keep the size of the grid relatively small, as opposed to creating a large grid that covers the entire path of the moving object. Motion Inertia can be used for moving ground and water vehicles, torches, fireballs, rockets, etc. When this option is used together with the Initial Fill Up option and Open Container Wall conditions, a simulation of moving an object over a sea surface can be done. For more information, see the Motion Inertia example below.

Gravity | grav, gmul – Phoenix Gravity makes the liquids fall down and makes fire rise up. The Gravity option is a multiplier, so using the default 1.0 will make it behave like real world gravity, setting it to 0.0 will disable its effect completely, and you can also use negative values, which will inverse the gravity effect.

Initial Fill Up | initfill, flevel – When enabled, the container is filled up with liquid when the simulation starts. This option determines the fill-up level, measured in % of the vertical Z size of the Grid. For liquid simulations using Confine Geometry, you can enable Clear Inside on the geometry and liquid will not be created at simulation startup in the voxels inside the geometry.

Fill Up For Ocean | oceanfill – Changes the Open Container Walls of the Simulator so they would act like there is an infinite liquid volume beyond them. Pressure will be created at the Simulator's walls in order to support the liquid, and if the surface of a wall below the Initial Fill Up level, or the bottom, gets cleared from liquid during simulation, new incoming liquid would be created. You can also animate the Simulator's movement or link it to a moving geometry, and it would act like a moving window over an ocean that stays in place. This way you can simulate moving ships or boats that carry their Liquid Simulator along with them as they sail into an ocean, so you don't need to create one huge long Simulator along their entire path.

In order to eliminate air pockets between Solid geometry and the liquid mesh, this option will automatically set all Solid voxels below the Initial Fill Up level to contain Liquid amount of 1, even if they don't contain any Liquid particles. If you don't want this effect, enable Clear Inside from the Chaos Phoenix Per-Node Properties of the Solid geometry. See the Fill Up For Ocean and Clear Inside example below.

 Steps Per Frame | spf – Determines how many calculations the simulation will perform between two consecutive frames of the timeline. For more information, see the Steps Per Frame example below.

Time Scale | timescale – Specifies a time multiplier that can be used for slow motion effects. For more information, see the Time Scale example below.

Default RGB | lq_default_rgb - The Simulator is filled with this RGB color at simulation start. The Default RGB is also used to color the fluid generated by Initial Fill Up, or by Initial Liquid Fill from the Chaos Phoenix Per-Node Properties of a geometry - both of these options create liquid only at the start of the simulation. During simulation, more colors can be mixed into the sim by using a Phoenix Liquid Source with RGB enabled, or the color of existing fluid can be changed over time by using a Phoenix Mapper. If a Phoenix Liquid Source does not have RGB enabled, it also emits using the Default RGB value.

RGB Diffusion | rgbdiff – Control how quickly the colors of particles are mixed over time during the simulation. When it's set to 0, each FLIP liquid particle carries its own color, and the color of each individual particle does not change when liquids are mixed. This means that if red and green liquids are mixed, a dotted red-green liquid will be produced instead of a yellow liquid. This parameter allows the colors of particles to change when the particles are in contact, thus achieving uniform color in the resulting mixed liquid. For more information, see the RGB Diffusion example below.

Default Viscosity | lqvisc – Determines the default viscosity of the liquid. Viscosity means how thick the liquid is. Liquids such as honey, syrup, or even thick mud and lava need to be simulated with high viscosity. On the other hand, liquid such as water, beer, coffee or milk are very thin and show have zero or very low viscosity. The Default Viscosity value is used when no viscosity information for the emitted liquid is provided to the Simulator by the Source. Also note that the effect of the viscosity works more strongly with more Steps Per Frame, and also when the grid resolution is lower. Increasing the grid resolution or reducing the Steps Per Frame can make viscous liquid thinner. For more information, see the Viscosity example below.

Viscosity Diffusion | viscdiff -  Phoenix supports sourcing of fluids with different viscosity (thickness) values. This parameter specifies how quickly they blend together. A low value will preserve the distinct viscosities, while a high value will allow them to mix together and produce a fluid with a uniform thickness.

Non-Newtonian |  nonnewt – Modifies the viscosity with respect to the liquid's velocity to overcome the conflict between viscosity and wetting, where a high viscosity of real liquids prevents wetting. Non-Newtonian liquids are liquids that behave differently at different velocities. This parameter accounts for this behavior by decreasing the viscosity in areas where the liquid is moving slowly and retains a higher viscosity where the liquid is moving quickly. For example, to cover a cookie with liquid chocolate, high viscosity is needed in the pouring portion of the motion to obtain the curly shape of the chocolate as it lands on the cookie and begins to settle down. On the other hand, a smooth chocolate is needed to settle in over the cookie without roughness and holes. If the viscosity is high enough, the chocolate might look right during the pouring and settling motions but won't settle in to form a smooth thin layer over the cookie. This parameter decreases the viscosity where the liquid is moving slowly (over the surface of the cookie) while keeping the faster-moving stream tight and highly viscous. For more information, see the Non-Newtonian example below.

Droplets Surfing | dsurf – This parameter affects the liquid and the splash particles, controlling how long a particle hovers on the surface before it merges with the liquid. The parameter is used mostly in ocean/wave simulations. For more information, see the Droplets Surfing example below.

Strength | lqsurft – Controls the force produced by the curvature of the liquid surface. This parameter plays an important role in small-scale liquid simulations because an accurate simulation of surface tension indicates the small scale to the audience. Lower Strength values will cause the liquid to easily break apart into individual liquid particles, while higher values will make it harder for the liquid surface to split and will hold the liquid particles together. With high Strength, when an external force affects the liquid, it would either stretch out into tendrils, or split into large droplets. Which of these two effects will occur is controlled by the Droplet Formation parameter. For more information, see the Surface Tension example below.

Droplet Formation | lqstdropbreak – Balances between the liquid forming tendrils or droplets. When set to a value of 0, the liquid forms long tendrils. When set to a value of 1, the liquid breaks up into separate droplets, the size of which can be controlled by the Droplet Radius parameter. For more information, see the Droplet Formation example below.

Droplet Radius | lqstdroprad – Controls the radius of the droplets formed by the Droplet Formation parameter, in voxels. This means that increasing the resolution of the Simulator will reduce the overall size of the droplets in your simulation.

Wetting | wetting – Enables the wetting simulation. The liquid will leave a trail over the surfaces of bodies it interacts with.

Consumed Liquid | lq2wet – Controls how many liquid particles disappear when creating a single WetMap particle. The main purpose of this parameter is to prevent long visible tracks from being left by a single liquid particle. For more information, see the Consumed Liquid example below.

Drying Time (sec) | drying – Controls the drying speed in seconds. The WetMap particles are born with a size of 1, and if they are in an air environment, the size decreases until it reaches zero after the time specified with this parameter.

Sticky Liquid | wetdyn – This option produces a connecting force between the WetMap particles at the geometry surface and nearby liquid particles. For more information, see the Sticky Liquid example below.

Active Bodies | use_activeBodySolverNode – Enables the simulation of Active Bodies. 

Active Body Solver | activeBodySolverNode – Specifies the Active Body Solver node holding the objects to be affected by the Phoenix Simulation. 

Interpolation | texuvw_interpol_influence – Blends between the UVW coordinates of the liquid particle at time of birth and its UVW coordinates at the current position in the Simulator. When set to 0, no interpolation will be performed - as a consequence, textures assigned to the fluid mesh will be stretched as the simulation progresses. This is best used for simulations of melting objects. When set to 1, the UVW coordinates of the fluid mesh will be updated with a frequency based on the Interpol.Step parameter - this will essentially re-project the UVWs to avoid stretching but cause the textures assigned to the fluid to 'pop' as the re-projection is applied. If you intend to apply e.g. a displacement map to a flowing river, set this parameter to a value between 0.1 and 0.3 - this will suppress both the effects of stretching and popping. See the Interpolation example below.

Interpol. Step | texuvw_interpol_step – Specifies the update frequency for the UVW coordinates. When set to 1, the UVWs are updated on every frame, taking into account the Interpolation parameter. See the Interpolation Step example below.