（以下英文部分及圖片皆來源於RealFlow官方文檔：http://support.nextlimit.com/pages/viewpage.action?pageId=22217380）
This type represents the standard “watery” substances, but is also used for highly viscous fluids, like chocolate or honey. RealFlow's liquids simulate very fast and they are perfectly suited to all kinds of projects with a demand for high detail, because they show even the finest drops and splashes. The liquid particle-based approach can be used for any field of operation where traditional fluids are required. In combination with daemons they open the door to a pretty-much endless variety of effects and applications.
該類粒子（Particles (Liquid)）用來模擬基本的液態物質，有時也用來仿真類似巧克力和蜂蜜的高粘度流體。RF的液體仿真非常快並且對所有對細節要求較高的項目都非常適用，因爲它會展現最佳的液滴與水花。基於液體粒子的方法可以用在需要傳統液體的任何操作領域。通過與daemons結合，開啓了一扇通往無限效果與應用的大門。
Type（類型）
This submenu allows you to define the fluid’s behaviour. By default, RealFlow generates fluid particles used for all kind of liquids. Fluid particles can interact with other fluid particles and support self-collision. They are affected by any of RealFlow’s internal or imported objects, including RealWave surfaces.
可通過此子菜單定義流體行爲。默認情況下，RF生成用作所有類型液體的粒子。流體粒子之間可以相互作用也支持自碰撞。它們受包括RealWave surfaces在內的RF所有內部對象與導入對象的影響。
“Gas” is used to create substances like air. Gas particles tend to very strong expansion and high velocities. RealFlow gases are not grid-based and therefore behave completely different from other solvers.
“Gas”用於創建像空氣一類的物質。Gas粒子易於擴散並且速度很快。RF氣體不是基於網格的，所以其表現與其他求解器完全不同。
“Liquid” is RealFlow’s standard setting and provides parameters for all watery or high-viscous substances. It is surely the most often used type and is suitable for all kinds of particle-object interactions, but especially for small to mid-range simulations. For larger projects, you should consider using the new grid-based fluid solver "Hybrido".
“Liquid”是RF的標準設置，爲所有類似水的或其他高粘度物質提供參數。所以它理所當然是最常使用的類型，並且適用於所有類型的粒子相互作用，特別是對小至中等尺度的仿真非常適用。對於更大的項目，可以考慮使用基於網格的新流體求解器“Hybrido”。
“Dumb” particles are perfectly suited for fast calculations of secondary effects, like spray or foam. Please keep in mind that these particles cannot react with each other and will not be affected by other emitters.
“Dumb”粒子特別適用於次生效果（如水花和泡沫）的快速計算。請記住，這些粒子不能相互作用，並且不會被其他emitter影響。
“Elastics” establishes a so-called spring-mass system between the particles, making them behave like a soft body. This option can be used for interesting effects like jelly-like fluids or expanding and contracting substances. Please note that elastic particles are not ruled by RealFlow’s soft body solver – that is a completely different system and can only be used with objects.
“Elastics”在粒子間建立了一個所謂的彈性質量系統，使粒子表現地類似於soft body（柔體）。該選項可以用來實現果凍一類的流體或擴散與收縮物質等有趣的效果。請注意，彈性粒子並不被RF的柔體求解器約束，它是一個完全不同的系統，並且只能用作objects。
“Script” gives you the opportunity to write your own fluid behaviour with Python scripting or C++. Choosing this type adds an “Edit” button to the menu. Clicking on “Edit” opens a new scripting window with a predefined function that is used to enter your source code. By default, this window does not contain any executable code.
“Script”可以讓你通過Python腳本或C++來自定義流體行爲。選擇該類型會在菜單中新增一個“Edit”按鈕。點擊“Edit”將開啓一個新的帶有預定義的功能的腳本窗口，用於輸入源代碼。默認情況下，該窗口不含任何可執行代碼。
Resolution（分辨率）
With this setting you can increase or decrease the amount of particles, and therefore it is one of the most important parameters. “Resolution” especially depends on scene scale and emitter scale, but it also affects the fluid’s mass and therefore depends on “Density”, too. By default, resolution is 1.0. A volume of 1 x 1 x 1 units filled with 1,000 particles has a mass of exactly 1,000 kg. In other words: Each particle has a mass of exactly 1.0 kg. By raising “Resolution”, an individual particle’s mass will be lowered and vice versa. You can monitor the relationship between mass and density under
通過本選項可以增加或減少粒子的數量，所以它是最重要的參數之一。“Resolution”取決於scene規模與emitter規模，但是它也影響流體的質量，所以也取決於“Density”（密度）。默認情況下，該參數爲1.0。一個1 x 1 x 1單位的體積填充1000個粒子，其質量爲1000kg。換句話說：每個粒子每個粒子重1.0kg。通過增大“Resolution”，每個單獨粒子重量將減小，反之亦然。可以通過以下路徑觀察質量與密度的關係
Statistics > Particle mass
Dependent on your scene, “Resolution” can dramatically increase, and values of 1,000 or even much higher are sometimes necessary. Another interesting issue – especially for scripting and plugin development – is the relation between “Resolution” and a particle’s radius, ruled by this formula:
“Resolution”可以根據所需場景顯著增加，1000或更大有時也是需要的。另一個有趣的問題——是特別針對腳本或插件開發的——“Resolution”和粒子半徑之間的關係，由以下公式確定：
radius = 1.0 / (1000.0 · Resolution1/3)
Density（密度）
“Density” is defined as mass per volume unit and is expressed in kilograms per cubic metre [ kg/m3 ]. Water, for example, has a density of
1000kg/m3. “Density” is different for each substance and for some fluids, like crude oil or honey, there are only average values available, because they consist of variable amounts of ingredients.
“Density”定義爲單位體積的質量，單位是kg/m3。以水爲例，密度爲1000kg/m3。不同物質與流體的“Density”不同，例如原油或蜂蜜，只能得到密度的平均值，因爲它們由不同組分組成。
Int Pressure（內部壓力）
Each fluid shows a more or less strong tendency to expand. With gases this behaviour can be observed best, but even liquid substances have this tendency. “Int Pressure” simulates the forces between nearby particles, and very high values make the fluid fill a greater volume. If “Int Pressure” is set to 0.0 the particles lose their fluid behaviour.
不同流體或多或少會展現出擴散的趨勢。氣體的此種趨勢最爲明顯，但是即使是液態物質也有此類趨勢。“Int Pressure”模擬相鄰粒子間的此種作用，該值越大流體所能填充的體積越大。如果將該值設爲0，那麼粒子將失去流體特徵。
Ext Pressure（外部壓力）
This is “Int Pressure’s” counterpart and tries to limit a fluid’s expansion tendency. With very high values it is possible to compress the fluid. Gases, for example, should have very low “Int Pressure” and rather high “Ext Pressure” values to prevent them from flying away. Both parameters are used to fine tune a fluid’s appearance and behaviour, therefore they are fundamentally important for a realistic simulation.
此值與“Int Pressure”相對應，其試圖限制流體的擴散趨勢。如果此值過高，可能會壓縮流體。對於氣體而言，其“Int Pressure”應該很小，而“Ext Pressure”應該很大，從而限制氣體粒子飛散。以上兩個參數都被用於調整流體的外觀與行爲，因此，若想仿真得到更加逼真的效果，它們很重要。
Viscosity（粘度）
Each fluid has a certain amount of viscosity, even water. It defines the tendency of particles to stick together. With very high values you can observe the typical strings in viscous fluids when they are torn apart. Substances with very high viscosity are honey, tar or syrup, for example. Fluids with low viscosity are alcohol, many solvents or liquid gases. Exaggerated settings can lead to misbehaving particles with high velocities.
每種流體都有一定的粘度，甚至是水。該參數定義了粒子附着在一起的趨勢。若該值很大，當黏流被分開時可以看到典型的細流。高粘度的物質有蜂蜜、焦油和糖漿，低粘度的有酒精、溶劑和液態氣體。若將該值設置的過大，會產生速度很大的異常粒子。
Surface tension（表面張力）
On a fluid’s surface we can observe forces that keep the outmost molecules together, creating a kind of skin. Some insects, such as water striders, can even walk on this tight skin. Surface tension can also prevent water from infiltrating cloth to dissolve the dirt. For that reason, detergents contain special substances to reduce the fluid’s surface tension”. These are called surfactants or tensides. A water drop’s shape is mostly a result of these forces.
在液體表面可以觀察到使最外層分子連成一體並形成一層表面的作用力。一些如水黽一樣的昆蟲甚至可以在這層表面上行走。表面張力還可以阻止水滲入衣物溶解污漬。所以，會在洗滌劑中加入特殊物質以降低水的表面張力（使水能夠滲入衣物，不至於聚集在一起，從而實現溶解污漬的作用），這些物質被稱作表面活性劑。水滴的形狀大部分也是表面張力作用的結果。
Interpolation（插值）
In some cases it is sufficient to raise the number of particles by selecting “Interpolation” instead of simulating the entire scene again. This feature gives you the possibility to generate more particles from an already cached BIN file sequence, but that is not the real idea behind this feature: “Interpolation” was originally introduced to simulate until a certain frame with low “Resolution”, stop, adjust to a higher value and resume. RealFlow analyses the fluid and places new particles where they will be safe. The new particles are not just filling the gaps, they completely satisfy the fluid engine’s equations.
在某些情況時，可以通過選擇“Interpolation”選項來增加粒子的數量，而不必對整個scene重新仿真一遍。該特徵使得通過現有緩存的BIN文件序列生成更多粒子成爲可能，但是在以下情況時該方法不適用：最開始引入“Interpolation”仿真，直至某低“Resolution”幀停止，調整至高“Resolution”，繼續。RF分析流體並將新粒子放在安全的地方。新生粒子不僅僅用於填充縫隙，它們完全滿足流體引擎方程。
RealFlow offers three options: “None”, “Local” and “Global”. Of course, “None” does not create any new particles and disables this function. The second options creates the new particles only within the existing fluid cloud with rather high accuracy. Please keep in mind that there are always some particles that will not fit. This is a good choice when the fluid should keep its shape. “Global” can be used when you do not have to worry about the original shape. The new particles will be created with some tolerance leading to slightly fuzzy edges. This solution is perfect for larger amounts of fluids, for example inside water tanks.
RF提供三個選項：“None”，“Local”和“Global”。當然，“None”不創建任何新粒子並使方程失效。第二個選項僅在現存流體雲中高精度地創建新粒子。請記住總有一些粒子不會適用。當流體應當維持其形狀時是一個好選項。當不必擔心初始形狀時可以使用“Global”選項，此時，生成新粒子時會有一定容差，並且導致邊緣略微有些模糊。該選項適用於大量流體，如水箱內部。
Another important thing about interpolation is fluid-object interaction. If a fluid is close to an object, it is very likely that new particles will suddenly appear inside the body. RealFlow does not check for collisions with objects and only examines the fluid.
關於插值另一件重要的事是fluid與object的相互作用。如果fluid接近object，新粒子很可能會突然出現在body裏面。RF不檢查與object的碰撞，只檢查fluid。
Compute Vorticity（計算渦量）
"Vorticity" hardly contributes to a fluid simulation, but it is a very important and interesting feature when you want to create rendered images. When you read out the BIN files' "Vorticity" channel and add it to add a shader you can create stunning and naturally looking results. The RenderKit mesh engine also supports "Vorticity", as well as the RFRK particle shaders. By default, this property is not simulated and you have to change the value to "Yes" if you want to make use of it. Please note that a particle's vorticity cannot be used to create the typical vortices of gas, fire or smoke.
“Vorticity”對於流體仿真意義不大，但是當你想要創建渲染圖時它將是一個重要且有趣的特徵。當你讀取BIN文件的“Vorticity”部分並着色時，你會創建一個令人吃驚又看起來很自然的結果。RenderKit（渲染工具）網格引擎也支持“Vorticity”和RFRK粒子着色器。默認情況下，仿真時不包含該屬性，如果想使用它需要將該值變爲“Yes”。請注意，粒子的vorticity不能被用於創建氣體、火焰與煙霧的典型渦。
Max Particles（最大粒子）
The pre-adjusted default value is also the maximum value, but it can be changed any time, if you need less. Under “Statistics” you can see two entries counting particles: "Existing Particles" and "Emitted Particles". “Max Particles” is connected to the latter value, and if you want to stop the emitter to create more particles you can enter a smaller value. Please note that "Max particles" is based on the total amount of emitted particles. Let's say you have entered "500,000", so even if you currently have only 1,000 particles in your scene, but have already deleted 499,000 particles, RealFlow will stop creating new particles.
之前調整過的默認值也是最大值，但是如果想變小可以隨時更改。在“Statistics”下有兩處入口計數粒子："Existing Particles"
（現存粒子）和 "Emitted Particles"（發射粒子）。“Max Particles”和後者相連，如果想停止emitter繼續生成更多粒子，可以輸入一個更小的值。應注意“Max particles”是基於已經發射的粒子的總數的。比如說，你輸入“500000”，那麼即使現在scene中僅有1000個粒子，並且已經刪除了499000個粒子，RF也會停止創建新粒子。