General

Parameters

General

This rollout controls the parameters regarding the simulation of liquids. Liquid is simulated in the temperature channel, value of 1 means presence of liquid, value of 0 means air. It's important to know that the air is also simulated, that may be very useful for simulations with moving boats, where the splash have to be affected by wind.

Parameters

Simulator Panel

Enable (MXS: liquid) - enable the liquids simulation.

 

Sharpness (MXS: lqsharpness) - the sharpness of the liquid-air interface. Bigger values result in more fine detail and better liquid behavior, but in some cases the grid cells can appear in the rendering. Lower values produce smoother liquid surface, but the liquid loses its surface and becomes more gaseous. This parameter is ignored when Strong surface mode is enabled.

 

Viscosity (MXS: lqvisc) - the viscosity (thickness) of the liquid. Bigger values require more time to calculate.

 

Drying time (MXS:drying) - the time needed for the liquid to evaporate.

 

Initial fill up (MXS:initfill,flevel) - allows the container to be filled up when the simulation starts. The numeric field determines the fill up level, measured in % of the Z size. When this option is used with open border conditions, you can move the container and the grid will behave as part of infinite sea.

 

Wetting (MXS:wetting) - when checked the liquid leaves a track over the surface of the bodies, that disappears slowly.

 

Static surface correction (MXS:flatliquids) - used to avoid the roughness of a slow moving or static liquid surface. When enabled, and the local movement is less than one cell per simulation cycle, the surface processing uses lower sharpness.

 

Strong surface mode (MXS strongsurf) - this option switches to a

different surface processing mode that suppresses grid artifacts, however the liquid becomes oily.

 

Strong surface mode is off
Strong surface mode is on



Foam group - This group affects the foam simulation

The foam simulation is carried out by an additional particle simulator that is closely connected to the main grid simulator. The simulation follows several simple rules: the underwater bubbles are rising up, the bubbles in the air are falling down, the bubbles can stick to each other and can resist to external pressure.

The foam may be born by the liquid, by the splash droplets, by source or by script. The foam disappears when it exits the grid (see the Outside life parameter), or randomly (see the Half life parameter).

 

Foam (MXS:foam) - enable foam simulation.

 

Birth rate (MXS:fbirth) - specifies the amount of particles to be born when a given cell meets the birth condition. This parameter does not affect the foam born by the splashes.

 

Birth threshold (MXS:fbthres) - when Phoenix FD simulates, a specific birth potential is calculated for each cell. This birth potential increases when the cell is more suitable to produce foam.
The birth is allowed when the above mentioned potential exceeds the value of this parameter.

 

Half life (MXS:fhlf) - the timespan when given bubble will burst with a probability of 50%.

 

Outside life (MXS:foutlife) - this parameter controls the maximum age of the foam outside the grid.

 

Size (MXS:fsize) - the size of the bubbles.

 

Size variation(MXS:fsizevar) - relative range of variation for the size of the bubbles.

 

Size distribution (MXS:fszdstrb) - how many times the count of the smallest bubbles exceeds the count of the biggest bubbles.

 

B2B interaction (MXS:fcycles) - controls the internal bubble to bubble interaction. This option is used when the foam should have a volume. It keeps proper distance between the bubbles and keeps them stuck together. This parameter controls the number of interactions per second. Bigger values result in better preservation of the foam's volume.

 

Rising limit (MXS:frise) - the maximal speed of ascent of nominally-sized bubbles toward the water surface. Bigger bubbles rise faster.

 

Falling limit (MXS:ffall) - the maximal speed of descent of the foam. WARNING! This parameter may dramatically affect the rendering speed. The falling limit parameter actually controls the drag force, thus affecting not only the falling, but the distance that a flying bubble may travel. A larger limit may lead to single bubbles thrown faraway from the simulator that leads to huge bounding box and slow rendering respectively

Sticky (MXS:fsticky) - controls the ability of the bubbles to stick to a geometry. This option needs the B2B interaction to be greater than zero.

 

Pattern forces (MXS:fptrn) - this parameter controls the simulation of the foam patterns caused by the fine vertical water movement.

 

Pattern size (MXS:fptrnsz) - the average size in scene units of the above mentioned patterns.

 

 

Pattern forces=0
Pattern forces=0.5
Pattern forces=1

 

Splash group - This group affects the splash simulation.

The splash simulation is carried out by an additional particle simulator that is closely connected to the main grid simulator. The simulation follows several simple rules: the bubbles in the air are falling down, with respect to the air friction. The droplets are born by the liquid, by the sources, by split of existing droplet, or by script. The droplets disappear when hit solid object, or when exit the grid (see the outside life parameter).

 

Splashes (MXS:splashes) - enable splashes simulation.

 

Birth rate (MXS:spbirth) - specifies the amount of the particles to be born when a given cell meets the birth condition.

 

Birth threshold (MXS:spbthres) - when Phoenix FD simulates, a specific birth potential is calculated for each cell. This birth potential increases when the cell is more suitable to produce droplets.
The birth is allowed when the above mentioned potential exceeds the value of this parameter.

 

Size (MXS:spsize) - the size of the droplets.

 

Size variation (MXS:spsizevar) - relative range of variation for the size of the droplets.

 

Size distribution (MXS:spszdstrb) - how many times the count of the smallest droplets exceeds the count of the biggest droplets.

 

Air friction (MXS:airfr) - the splash simulation takes into account the size of the droplets and the corresponding friction with the air is calculated. This parameter is a multiplier; a value of 1 means that the friction is corresponding to the real one.

 

Foam on hit (MXS:sp2foam) - controls how many foam bubbles to be created when a single droplet hits the surface. This parameter works in terms of probability and non-integer values can be used as well.

 

Outside life (MXS:timeout) - this parameter controls the maximum age of the droplets outside the grid.

Velocity multiplier (MXS:spvmult) - when the droplets are born, they are initialized with the velocity of the nearest liquid, multiplied by this value. This parameter is very important for the general appearance of the splash. When it is below 1, the droplets are flying in front of the splash and are producing a clearly visible track of droplets.

 

Split rate (MXS: spsplit) - this parameter allows the droplets to split into smaller droplets, in order to produce more realistic splash appearance. Not all the droplets can be split (only the big ones). It is important to know that this option may produce droplets much smaller than the ones specified by the size parameter, and they may form a slowly falling mist.