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Domain Whitewater Settings

Ryan Guy edited this page Jan 31, 2019 · 4 revisions

This page documents the domain settings for the 'FLIP Fluid Whitewater' panel.

Parameters

All parameters in this panel must be set before baking for changes in the simulation to take effect.

Enable Whitewater Simulation Enable the whitewater foam/bubble/spray particle solver
Settings View Mode How to display the settings in the panel UI.
Basic
    Display only the basic and most important whitewater settings. Most simulation scenarios will only need to adjust these parameters.
Advanced
    Display all parameters for full customization of whitewater behaviour. Settings in this documentation will denote an advanced setting with an (A) symbol next to the parameter name.
Highlight Advanced Settings Enabling this option will highlight advanced settings with a red color in the UI. This setting is only available if Settings View Mode is set to Advanced. Settings in this documentation will denote an advanced setting with an (A) symbol next to the parameter name.

Whitewater Particles

Foam (A) Enable solving for foam particles. Foam particles form a layer on the fluid surface and are advected with the fluid velocity. If disabled, any particles that enter the foam layer will be destroyed.
Bubble (A) Enable solving for bubble particles. Bubble particles below the foam layer are advected with the fluid velocity and float towards the foam layer against gravity. If disabled, any particles that move below the foam layer will be destroyed.
TIP: Bubble particles are a large contributor to the foam layer and disabling may severely limit the amount of generated foam
Spray (A) Enable solving for spray particles. Spray particles above the foam layer are simulated ballistically with gravity. If disabled, any particles that move above the foam layer will be destroyed.

Whitewater Emission Settings

Enable Whitewater Emission Allow whitewater emitters to generate new foam/bubble/spray particles
Emitter Generation Rate (A) Amount of whitewater emitters that the solver may generate. Emitters are generated within the fluid at wavecrests and in areas of high turbulence.
Wavecrest Emission Rate Maximum number of whitewater particles that a wavecrest emitter may generate per simulation second.
Turbulence Emission Rate Maximum number of whitewater particles that a turbulence emitter may generate per simulation second.
Min Curvature (A) When the wavecrest curvature around an emitter is less than this value, the emitter will generate no whitewater particles.
Max Curvature (A) When the wavecrest curvature around an emitter lies in the range of Min Wavecrest Curvature up to this value, proportionally increase the rate of generated whitewater particles up to the Wavecrest Emission Rate.
Min Turbulence (A) When the fluid turbulence around an emitter is less than this value, the emitter will generate no whitewater particles.
Max Turbulence (A) When the fluid turbulence around an emitter lies in the range of Min Turbulence up to this value, proportionally increase the rate of generated whitewater particles up to the Turbulence Emission Rate.
Min Energy Speed When the fluid speed around an emitter is less than this value, the emitter will generate no whitewater particles.
Max Energy Speed When the fluid speed around an emitter lies in the range of Min Energy Speed up to this value, proportionally increase the rate of generated whitewater particles up to the emitter's generation rate.
Max Particles Maximum number of particles (in millions) that the whitewater solver is allowed to simulate. The solver will stop generating new whitewater particles to prevent exceeding this limit.
Enable Emission Near Domain Boundary (A) Enable whitewater emitters to generate particles at the edges of the domain bounding box.

Whitewater Particle Settings

Foam

Advection Strength The strength of the advection force that carries the foam with the fluid velocity. High values cause tighter streaks of foam that closely follow the fluid motion. Lower values will cause more diffuse and spread-out foam.
Depth (A) The thickness of the foam layer.
Offset (A) The height offset of the foam layer in relation to the fluid surface. If set to a value of 1.0, the foam layer will rest entirely above the fluid surface. If set to a value of -1.0, the foam layer will rest entirely below the fluid surface.
Preseve Foam Increase the lifespan of foam based on the local density of foam particles, which can help create clumps and streaks of foam on the fluid surface over time.
Preservation Rate (A) Rate to add to the lifetime of preserved foam. This value is the number of seconds to add per second, so if greater than one can effectively preserve high density foam clumps from ever being killed.
Min Foam Density (A) When the local foam density around a foam particle is less than this value, the lifespan of this particle will not increase. Foam density units are in number of foam particles per domain grid cell.
Max Foam Density (A) When the local density around a foam particle lies in the range of Min Foam Density up to this value, proportionally increase the lifespan of the particle up to the Preservation Rate. Foam density units are in number of foam particles per domain grid cell.

Bubble

Drag Coefficient Controls how quickly bubble particles are dragged along with the fluid velocity. If set to 1.0, bubble particles will be immediately dragged into the flow direction of the fluid.
Buoyancy Coefficient Controls how quickly bubble particles float towards the fluid surface against gravity. If set to a negative value, bubbles will sink away from the fluid surface with gravity.

Spray

Drag Coefficient The amount of air resistance on a spray particle.

Particle Lifespan Settings

Min Lifespan Minimum whitewater particle lifespan in seconds.
Max Lifespan Maximum whitewater particle lifespan in seconds.
Lifespan Variance A random number of seconds in this range will be added or subtracted from the whitewater particle lifespan.
Foam Lifespan Modifier Multiply the lifespan of foam particles by this value.
Bubble Lifespan Modifier Multiply the lifespan of bubble particles by this value.
Spray Lifespan Modifier Multiply the lifespan of spray particles by this value.

Particle Behaviour at Domain Boundary

Foam Boundary Behaviour (A) Specifies foam particle behaviour when hitting the domain boundary.
Collide
    Collide with boundary limits.
Ballistic
    Make foam particle follow ballistic trajectory when outside of boundary limits.
Kill
    Kill foam particles when outside of boundary limits.
Bubble Boundary Behaviour (A) Specifies bubble particle behaviour when hitting the domain boundary.
Collide
    Collide with boundary limits.
Ballistic
    Make bubble particle follow ballistic trajectory when outside of boundary limits.
Kill
    Kill bubble particles when outside of boundary limits.
Spray Boundary Behaviour (A) Specifies spray particle behaviour when hitting the domain boundary.
Collide
    Collide with boundary limits.
Ballistic
    Make spray particle follow ballistic trajectory when outside of boundary limits.
Kill
    Kill spray particles when outside of boundary limits.
Active Foam Behaviour Sides (A) Specify the sides of the domain where the Foam Boundary Behaviour is active. When a side is not active, Collide behaviour will be used. This setting only applies to Ballistic and Kill behaviours.
Active Bubble Behaviour Sides (A) Specify the sides of the domain where the Bubble Boundary Behaviour is active. When a side is not active, Collide behaviour will be used. This setting only applies to Ballistic and Kill behaviours.
Active Spray Behaviour Sides (A) Specify the sides of the domain where the Spray Boundary Behaviour is active. When a side is not active, Collide behaviour will be used. This setting only applies to Ballistic and Kill behaviours.

Obstacle Settings

This UI section lists the FLIP Fluid Obstacle objects present in the scene with their corresponding Whitewater Influence parameters.

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