This page provides information on the Simulation rollout for a FireSmokeSim object.


The Simulation roll-out contains the main panel for controlling the simulation process. It displays statistical information for simulation times and the content of the cache file for the current frame. The content can be grid channels such as Temperature or Velocity, or particle groups. You can select which channels are exported to the cache file from the Output rollout, while the particle groups are automatically created by the Simulator.

Most simulations require long time to calculate and it's very convenient to let them run during the night. However, you still have to render the result in the morning and this also consumes a lot of time. The Phoenix FD scripting system allows you to execute any action at the end of the simulation, and that includes the rendering as well. You just have to enable the scripting from the Simulation roll-out and open the script text. For more information, see the Nightly Simulation and Rendering section on the Tips and Tricks page.

 UI Path: ||Select Fire Smoke Simulator | FireSmokeSim|| > Modify panel > Simulation rollout





Start, Pause, Stop, Resume | A_StartSim, A_StopSim – Starts, pauses and stops the simulation. Once the simulation has been paused, the option to Resume becomes available.

Load & StartA_StartSim – Loads the data from a single cache as an initial state for the simulation and starts simulating from the Start Frame the same way the Start action works. The cache can be of the .aur, .vdb, or .f3d formats and so can be imported from a 3rd party software into Phoenix. The loaded grid will be resized to fit the grid's dimensions at the Start Frame. The loaded cache does not need to be a Backup frame or to contain velocity at all - the simulator will load any available channels from the cache file and the rest of the simulated channels will be empty as when starting a brand new simulation. If you wish to smoothly continue a simulated sequence from a given frame, please use the Restore command instead.

RestoreA_StartSim – Continues a simulation from the currently viewed frame on the timeline. This way a Phoenix simulation that has been stopped previously can be resumed from the point you left off, even after the software was closed and re-opened.

Restoring does not work for cache sequences imported from 3rd party software. It is only possible when the full internal state of a Phoenix simulation is exported (controlled by the Backup Interval parameter in the Output rollout). Frames with the full state are called Backup frames. When a Backup frame is currently viewed, the text "Can Restore From Here" appears in the Cache File Content list. The Restore command finds the latest Backup frame up to the current timeline frame and continues the simulation from there.

Preferences... – Opens up the Phoenix FD Global Preferences window.

? – Opens up the help documents for the Simulation process.

About – Opens a window with information pertaining to the build of Phoenix currently installed. Log files can be created through this window.

Simulation Presets... | A_LoadRenderPreset – Displays a drop-down menu to either load or save .tpr or .slog files, which hold settings for this simulation.





Start Frame | startframe – Explicitly sets the Start frame of the Simulation. This can also be a negative number. Only available when Timeline (Start Frame) is disabled.

Timeline | parmName - When enabled, the Simulation will run from the Timeline Start Frame.

Stop Frame | stopframe – Explicitly sets the End frame of the Simulation. This can also be a negative number. Only available when Timeline (Stop Frame) is disabled.

Timeline | parmName - When enabled, the Simulation will run to the end of the Timeline. 

Use Script | script, use_script – Enables the use of a MAXScript during the simulation. Press Edit... to open a window with sample code and a short description of available commands. For more information, please see the Phoenix MaxScript documentation.

Threads Limitmaxthreads – Specifies an upper limit on 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 Nodes– Specifies which nodes will be used if the simulation is executed by a NUMA machine. Phoenix FD is very sensitive to the memory transfer and if all the nodes are used, performance might decrease due to low bandwidth between the different nodes.

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


Cache File Content

This area displays information on the current simulation. Any data from channels that have been loaded into the simulator are shown. This includes the minimum and maximum ranges for each channel. Check the Grid Channel Ranges and Particle Channel Ranges pages for more information.

Note that the Container Dimensions show the loaded cache size as seen in the scene, in the currently selected units. This size is not multiplied by the Scene Scale parameter from the Grid rollout. If you want to see how big the container is as seen by the Phoenix simulator when the Scene Scale parameter is used, check the XYZ info in the Grid rollout.



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