- Overview 綜述
- Parameters 參數
綜述
The foam simulation follows several simple rules: underwater bubbles rise up, bubbles in the air fall down, bubbles can stick to each other and can be resistant to external pressure.
泡沫模擬遵循幾個簡單的規則:水下泡沫上升，空氣中的泡沫下降，泡沫可以相互粘在一起，可以抵抗外部壓力。
The foam may be born from the liquid, splash droplets, a Source, or a script.泡沫可能是由液體、飛濺的液滴、源或腳本生成的。
The foam disappears when it exits the grid (see the Max Outside Age parameter), or randomly (see the Half Life parameter). 退出網格時泡沫消失(見最大外部年齡參數)，或隨機(見半衰期參數)。
You can see the FLIP Particles Life Cycle for more information on how Foam particles are created or destroyed.您可以查看FLIP粒子的生命周期，了解更多關於泡沫粒子是如何創建或銷毀的信息。
UI Path: ||Select Liquid Simulator | LiquidSim object|| > Modify panel > Foam rollout
參數
Enable | foam – Enables the birth and simulation of Foam particles. 啟用泡沫
產生
Foam Amount | fbirth – Specifies the number of particles to be born when a given cell meets the birth condition, in thousands per second.指定給定細胞滿足出生條件時要出生的粒子數，單位為每秒數千個。
This parameter does not affect the foam born by splashes.此參數不影響飛濺產生的泡沫。
Birth Threshold | fbthres – Foam birth occurs when a liquid experiences turbulent movement.當液體經歷湍流運動時就會產生泡沫。值越大越不容易產生泡沫。
This parameter specifies the velocity threshold above which the liquid is considered turbulent enough for foam birth.這個參數指定了速度閾值，超過這個閾值，液體就被認為是足夠湍流的泡沫誕生。
This is measured as the difference in velocity at a distance of 1. 這是用距離為1時的速度差來測量的。
For more information, see the Birth Threshold example below.
Birth Volume | usefbconfgeom, fbconfgeom – When enabled, allows the foam to be born naturally by the simulation only inside a specified geometry object.當啟用時，只允許泡沫在指定的幾何對象內通過模擬自然生成。
This includes foam born according to the conditions set by the Foam Amount and Birth Threshold parameters of the Foam, as well as the Foam on Hit parameters of the Splash.
這包括根據泡沫數量和泡沫的出生閾值參數所設定的條件所產生的泡沫，以及泡沫對飛濺命中參數的影響。
The foam born inside the Birth Volume can travel outside the volume without a problem.在出生體積內產生的泡沫可以毫無問題地在體積外移動。
The difference between this approach and spawning foam inside a volume manually from a Source object is that using a Birth Volume, the foam birth will follow the simulation criteria of the simulation and will look and behave more naturally.這種方法與從源對象手動在卷中生成泡沫的區別在於，使用此方法，泡沫生成將遵循模擬的模擬標准，並且看起來和行為都更加自然。
！ By default, the birth volume geometry is not automatically converted to a non-solid and it will behave as a rigid body in your simulation.默認情況下，出生體幾何形狀不會自動轉換為非實體，在模擬中它將表現為剛體。
In this case, the Volume Fadeout can be used to expand an area around the object where Foam/Splash births are possible.在這種情況下，可以使用體淡出來擴展對象周圍可能出現泡沫/飛濺的區域。
You can convert the geometry to a non-solid from its PhoenixFD properties.您可以將幾何圖形從PhoenixFD屬性轉換為非實體。
Volume Fade Dist | fbconfgeomfade – Controls how far the foam particles will spawn around the specified Birth Volume geometry object.控制泡沫顆粒圍繞指定的出生體幾何對象產生的距離。
壽命
！ The particle Age channel must be exported in order for these options to take effect (from the Source or from the Output panel, depending on the way the foam is generated).
為了使這些選項生效，必須導出顆粒年齡通道(從源或從輸出面板，取決於泡沫的生成方式)。
Half Life | fhlf – The time span when a given bubble will burst with a probability of 50%, in seconds.給定泡沫破裂的概率為50%的時間跨度，以秒為單位。
Affects only the foam bubbles above the liquid surface - those inside the volume will not burst until they reach the surface.只對表面泡沫起作用。
You can force this process by increasing the Rising Speed.
Vary | hlvary – In nature, not all the bubbles have the same half life.在自然界中，並不是所有的泡泡都有相同的半衰期。
Bigger bubbles burst quicker than smaller ones, and bubbles inside foam live longer.大泡泡比小泡泡破裂得更快，泡沫內的泡泡壽命更長。
When this option is enabled, the Half Life of each bubble is modified taking into account its size and its surroundings.啟用此選項后，每個氣泡的半衰期將根據其大小和周圍環境進行修改。
Max Outside Age | foutlife – If a particle exits the grid, and its age (in seconds) exceeds this parameter, the particle will be killed instantly.如果一個粒子離開網格，並且它的年齡(以秒為單位)超過這個參數，這個粒子將立即被殺死。
尺寸
Size | fsize – Specifies the size of the bubbles.指定泡沫尺寸。
！ Larger bubbles rise faster while they are underwater, while smaller ones rise more slowly.在水底，大泡沫上升的快。
Variation Small | fshrink – Specifies how much smaller the bubbles can be, relative to the Size parameter. 指定相對於Size參數，氣泡可以小多少。
0 means that all bubbles are always at least as big as Size. 1 means that the smallest bubbles are two times smaller than Size. 10 means that the smallest bubbles are 11 times smaller than Size. For more information, see the Variation Small example below.
Variation Large | fsizevar – Specifies how much larger the bubbles can be, relative to the Size parameter.
0 means that all bubbles are never larger than Size. 1 means that the largest bubbles are two times larger than Size. 10 means that the largest bubbles are 11 times larger than Size. You can also use the Distribution parameter to control the balance between the number of small and large bubbles.
Distribution | fszdstrb – Specifies how many times the amount of average bubbles exceeds the amount of the biggest bubbles. 指定平均氣泡數量超過最大氣泡數量的多少倍。
0 means that all sizes will be equally distributed. 100 means that there will be 100 times more bubbles with the average size than the biggest ones. For more information, see the Distribution example below.
動力學
B2B Interaction | fcycles – Controls the internal interaction between bubbles (bubble-to-bubble interaction).控制氣泡之間的內部相互作用(氣泡與氣泡之間的相互作用)。
This option is used when the foam should have a volume. It forces a proper distance between the bubbles and keeps them stuck together. This parameter controls the number of interactions per second. Higher values result in better preservation of the foam's volume. This parameter has linear growth order. In other words, the time taken for calculation is longer when the value is higher. For more information, see the B2B Interaction below.
Rising Speed | frise – Affects only the foam particles which are inside the liquid volume.水中氣泡上升速度。
This is the maximal speed of ascent of the average-sized bubbles. Bubbles larger than Size rise faster and smaller bubbles rise more slowly. Note that bubbles inside the liquid volume are carried by the velocity of the liquid, and also affected by this parameter. For more information, see the Rising Speed example below.
Falling Speed | ffall – Affects only the foam particles which are outside of the liquid volume. 氣泡下落速度。
This parameter controls the drag force of foam flying through the air. Lowering this parameter towards zero would cause foam to rapidly slow down when flying in the air, or hang in the air for a long time until it falls down. Note that this parameter affects only foam which is outside the liquid volume, while foam inside of the liquid mesh or which is mixed up with flying Liquid particles would have the same velocity as the liquid. In the second case, if the Falling Speed is too low, the foam might abruptly slow down at the moment it separates from the liquid that carries it. as For more information, see the Falling Speed example below.
！The Falling Speed parameter affects how far a flying foam particle may travel.下降速度參數會影響飛行的泡沫顆粒的飛行距離。
A higher Falling Speed may lead to separate bubbles thrown far away from the simulator which leads to huge bounding box and thus slower rendering. 較高的下降速度可能會導致分離的氣泡拋出遠離模擬器，這將導致巨大的邊界框，從而降低渲染速度。
Therefore, this parameter can dramatically affect the rendering speed.
Sticky Foam | fsticky – Controls the ability of the bubbles to stick to a geometry.控制氣泡粘附在幾何體上的能力。
This option requires that the B2B interaction is greater than zero.此參數要求B2B的值大於0。
Surface Lock | fsrflock – Affects the bubbles placed on the liquid surface.影響放置在液體表面的氣泡。
It controls the influence of the liquid movement over the surface bubbles.它控制液體表面運動對氣泡的影響。
In most cases, this parameter is used together with the patterns generator.在大多數情況下，此參數與模式生成器一起使用。
It can dramatically change the result.它可以極大地改變模擬結果。
樣式
Strength | fptrn – Controls the simulation of the foam patterns caused by the fine vertical liquid movement. 控制模擬泡沫形態引起的精細垂直液體運動。
For more information, see the Strength example below.
Radius | fptrnsz – The average radius in scene units of a single circular pattern core.單個圓形圖案核的場景單位的平均半徑。