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This page introduces the Fire Smoke Simulator object (PhoenixFDSimulator) and its rollouts.

Overview

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The

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Fire/Smoke simulator is intended to produce gaseous effects like fire, smoke

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and

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explosions, as well as sparks or embers.

You can think of a Phoenix Simulator as a 3D box, inside which simulations of fluids and Rigid Body Dynamics are performed. The box is divided into small cells, called voxels, which is why the box is referred to as a Simulation Grid. The voxels inside the grid can be filled with just about any type of gas or liquid, and contain the fluid's properties at a position and given time.

These fluid properties are written inside what are called Grid Channels. Each channel stores a type of value, such as Temperature or Velocity, with its own Grid Channel Range, which is the range of possible values that is most efficient for that specific channel type. Phoenix determines the fluid’s behavior at a given time, based on the content of these Grid Channels.

When running a simulation, the Fire/Smoke sim will typically output an entire animation sequence. That sequence is saved as individual files, called caches, which contain raw simulation data for each timeline frame. In essence, the cache data contains grids and particles, which describe the fluid’s behavior.

Fire/Smoke sim cache files can then be previewed in the viewport, as well as rendered, in order to create captivating and realistic images. The simulator offers multiple render modes, where the volumetric render modes are typically used for rendering Fire/Smoke sims, and the mesh render mode is typically used for Liquid sims. Phoenix offers a lot of flexibility though, so there is the option to render Fire/Smoke sims as meshes and Liquids as volumes, in order to achieve even more diverse effects.

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Note that the simulator is represented as a single object for

Liquid simulations use the FLIP solver in Phoenix 3.0. Compared to the previous grid-based solution, FLIP provides the following:

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  • More realistic simulation
  • No stepping artifacts
  • Faster simulation

 

In addition liquid simulation, the simulator provides built-in helper simulators for foam, WetMap, splash, and mist. In certain cases the splash and mist can be considered as part of the liquid simulation, because liquid, splash and mist can be converted to each other.

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convenience. Internally, it contains two completely separate parts: a simulator component and a rendering component. Parameters that control the

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simulation are separated from those associated with the shading and rendering

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processes. As a result, no

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roll-out will contain mixed parameters, and no parameter will affect both the simulation and rendering.

In addition to manual creation of a simulator with the UI paths shown below, a simulator is automatically created when any of the Quick Simulation Setup buttons are used.

Note: In addition to a simulator, a Source Component must also be present in the scene in order for simulation to take place.

 

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 UI

UI Paths:

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||Phoenix FD menu|| > Create >

3D

||Phoenix FD Shelf|| > Create Phoenix FD 3D Fluid Simulator button

 

Fire/Smoke Simulator

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||Phoenix FD Shelf|| > Create Phoenix

FD 2D Fluid

Fire/Smoke Simulator button

 

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Rollouts

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After creating a PhoenixFD Phoenix Simulator object, the following rollouts can be accessed in the Attribute Editor:

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  • Simulation - Controls the simulation and displays statistical information.statistics such as simulation times, as well as information about the data contained in the sim for the current frame.

  • Simulation Speed - Helps identifying the heaviest computation phases of the simulation and provides tips on how to get results faster and more efficiently.

  • Resimulation - Uses a base simulated cache sequence with exported velocity to drive a new simulation. Capable of adding time effects, increasing the resolution, etc, in order to enhance details, increase its resolution, or slow down or speed up the simulation. For liquid simulations, it modifies an existing cache sequence to improve features or change specified particle systems.
  • Grid - Controls the boundaries, size and resolution of the simulation grid.
  • Dynamics - Controls fire dynamics Offers parameters to affect fire/smoke dynamics when simulating, such as cooling, smoke dissipation, vorticity, advection, etc.
  • Fuel - Controls the simulation of burning when Fuel is present in the simulation for special effects such as , which is useful for creating gasoline explosions or propagating fire effects.
  • Liquid - Controls liquid dynamics such as viscosity, surface tension, drying time, etc.
  • Foam - Controls bubbles and foam.
  • Splash and Mist - Controls splash and mist simulation.
  • Scene Interaction - Specifies how the simulator interacts with other objects in the scene.
  • Output - Specifies how and where the simulation cache files are saved.
  • Input - Determines the path of the input files for rendering and previewing.
  • Scene Interaction - Specifies how the simulator interacts with other objects in the scene.
  • , and offers settings and controls for playback.
  • Preview - Controls how the simulation is displayed in the viewport.
  • Rendering - Controls how the simulation is rendered, and includes additional volumetric options .

 

Simulation in 2D

The Phoenix simulator has the ability to perform a 2D simulation if one of the grid dimensions is set to 1. The main application of this feature is to create very wide fires that would otherwise be difficult with 3D simulation. See the Grid rollout for more information.

  • for shading Fire/Smoke simulations.
  • Presets – Allows the parameters of the simulator to be saved to your storage, and then loaded back as a preset.

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Upgrading from Previous Versions of Phoenix

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Due to many improvements to the Phoenix solver, recreating simulations the same way you did in older versions of Phoenix may not be possible because of changes to the solvers and the UI. Here are some things to be aware of when upgrading from older versions of Phoenix FD.


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  • If you have a scene created with Phoenix

    v.2

    version 3 and you open it with version

    3

    4, it will keep all the old settings for you, including some

    of

    which are not visible to newer versions

    and the result should

    , in order for the results to be roughly the same.

  • If you try to manually replicate

    the same

    an older simulation setup with

    Phoenix v.3

    a new Phoenix simulator using Phoenix version 4, and set all the parameters with the same values as the older version, you

    would

    may not obtain the same result

    . The new simulation will be different because Phoenix v.3 uses

    as in Phoenix version 3 or older.

  • Since the release of Phoenix version 3, Phoenix started using a new solver for liquids and fire/smoke

    .

 

 

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  • simulations, so simulation results will be different between Phoenix version 3 and version 2.