Material Transfer (Advection)

Scene Interactions



The parameters in this rollout control the main aspects of the simulation. Note that only one simulation can be run at a time for each Maya instance.


Simulator Panel

Elapsed, Estimated Left, Cells Per Sec, Steps Per Frame, Frame, Total - output attributes to show various information while simulating.

Required RAM - shows approximately how much memory the simulation will need.

Note The required RAM is only calculated for the known state of the fluid, i.e. doesn't take into an account the grid adaptation and particles/foam/splashes generation.

Threads Limit threadsLimit - allows you to specify an upper limit for the number of threads used for the simulation. When the value is set to "0" the maximum number of threads(cores) will be used.

NUMA Node Start NUMANode0 - if Threads Limit is 0, this parameter specifies the starting index of the NUMA nodes that will be used for simulation.

NUMA Node End NUMANode1 - if Threads Limit is 0, this parameter specifies the end index of the NUMA nodes that will be used for simulation.


Note NUMA stands for Non-Uniform Memory Access and currently is available only on Windows. NUMA can be used to restrict the threads used for simulation based on the physical CPUs available on the system (in a multiprocessor systems). In this way better memory access can be achieved when multiple simulations are run on the same machine.

Start Frame startFrame - the starting frame of the simulation.


Stop Frame stopFrame - the ending frame of the simulation.

Skip Dynamics Before Start Frame skipStartFrames - if checked, the simulation will jump right to the starting frame. Otherwise, it will evaluate the Maya dynamics frame by frame from the beginning of the time slider.


Use script useScript - enables using Mel or Python script during the simulation


Script File scriptFile - Mel or Python script file to use during the simulation.


Python Help - shows a quick usage information about the phxfd Python module inside the Script Editor.


Edit Script - opens the script file in the default external editor.


See Also Scripting with Mel and Python


For detailed explanation of the conservation meaning see the simulation workflow.


Method conservMethod - choose between different methods for evaluating the conservation.


Symmetric - this method is suitable for simulations which require a high degree of symmetry e.g. a nuclear mushroom.


Smooth - this is the strongest conservation method, it is recommended for liquids and also for simulations where the pressure has an important role.


Buffered - this method is suitable for fire and smoke. Produces more fine details compared to the other methods. Can't be used for liquids.


Smoke simulated with symmetric type of conservation Smoke Simulated with smooth type of conservation Smoke simulation with buffered type of conservation




Quality conservQuality - this parameter controls how many conservation cycles per single simulation step to be applied. For liquid simulations, the recommended value of this parameter is at least 20 (the default 8 is for smoke).



Uniform density conservUniform - controls whether or not the mass of the fluid will be considered during the simulation. The effect of the mass is considered when this box is not checked.


Material transfer (Advection)


For detailed explanation of the advection meaning see the simulation workflow.

The advection is closely related to one very important parameter of the simulation - the SPF, and because of this, the control over the SPF is also placed in this section.


Method advMethod - specifies the algorithm used for calculating the advection


Classic(Semi-Lagrangian) - this is the most commonly used algorithm for advection. Has good stability , the only method that can achieve settled liquids, but does not strictly conserve the quantity of the transferred material.


Slow Moving - this method is a modification of the Semi-Lagrangian method optimized for slow moving fluids and preventing the numerical dissipation.

Note This method is not recommended for liquids.


Forward Transfer - good conservation abilities, but less stability compared to the classic method. Tends to produce cross-like artifacts when used with liquids.

Maximal Step advMaxStep - this parameter is used in the automatic SPF adjustment. Advection step X means that in one simulation cycle the fastest point in the fluid will be moved at distance X cells. Bigger advection step produces lower SPF value.

SPF (Steps Per Frame) Upper Limit advSPFU - if the value calculated in the automatic SPF adjustment is above this value, it is ignored and this value is set as SPF.

SPF (Steps Per Frame) Lower Limit advSPFL - if the value calculated in the automatic SPF adjustment is below this value, it is ignored and this value is set as SPF.


SPF=1 SPF=1.5 SPF=2



Start phxfdSim -a "start" -node $node - start the simulation.

Pause phxfdSim -a "pause" - pause the current simulation.

Stop phxfdSim -a "stop" - stop the current simulation.

Restore phxfdSim -a "restore" -node $node - if the velocity channel is exported, Phoenix is able to restore the simulation. This command finds the nearest file containing velocity channel behind the time slider and continues the simulation from it (see Backup interval parameter)


Load phxfdSim -a "restore" -fname $file -node $node - loads the content of a chosen cache file as initial state for the simulation.

Auto Save Before Simulation autoSave - saves the scene before simulating.