Liquid

This page provides information on the Liquid rollout.

Overview

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This rollout controls the fluid's liquid motion parameters.

 

Parameters

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Enabled | liquid – When enabled, turns on liquid simulation.

Simulate Air Effects | liqSimAirEffects – When enabled, turns on the built-in air simulator. Strong sources or fast moving obstacles inside the simulator will create air velocities to carry splash, mist, and foam particles at high speed. Used mostly when realistic mist is needed. The simulation is not expensive, but can dramatically increase the splash and mist quality.

Initial Fill Up | liqFillUp – When enabled, the container is filled up with liquid when the simulation starts. The numeric field determines the fill-up level, measured in % of the Y size.
When this option is used with open Container Walls, the container can be moved and the grid will behave as part of an infinite ocean. 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 | liqOceanFill – Change the Open Container Walls of the simulator so that they would act like there is an infinite liquid volume beyond them. Pressure would be created at the simulator walls in order to support the liquid, and if the surface of a wall below the Initial Fill Up level or the bottom is cleared from liquid during simulation, new incoming liquid would be created. 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 Phoenix FD Attributes of the Solid geometry.

Default RGB | liqDefaultRGB – 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 Phoenix FD 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 FD Liquid Source with RGB enabled, or the color of existing fluid can be changed over time by using a Phoenix FD Mapper. If a Phoenix FD Liquid Source does not have RGB enabled, it also emits using the Default RGB value.

RGB Diffusion | liqRGBDiffusion – 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 | liqViscosity – Determines the default viscosity of the liquid. This value is used when no viscosity information for the emitted liquid is provided to the Simulator by the Source. For more information, see the Viscosity example below.

Viscosity Diffusion | liqViscDiffusion – Phoenix FD 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 | liqNonNewtonian – Modifies the viscosity with respect to the liquid's velocity to overcome the conflict between viscosity and wetting, where 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 | liqDropletSurf – 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.

Surface Tension | liqSurfTension – 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 Surface Tension 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 Surface Tension, 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 Breakup parameter. For more information, see the Surface Tension example below.

Droplet Breakup | liqSurfTDropBreak – 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 Breakup example below.

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

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

Consumed Liquid | liqWetConsumeLiq – 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) | liqDryTime – 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 | liqWetSticky – This option produces a connecting force between the WetMap particles at the geometry surface and nearby liquid particles, when the liquid particles have at least a little Viscosity. For more information, see the  Sticky  Effect example below.

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

Set Selected Object as Active Body Solver | activeBodySolverNode – Specifies the Active Bodies Solver node holding the objects to be affected by the Phoenix FD Liquid Simulation.