The toolbar that stretches across the top of the FumeFX UI dialog specifically involves simulations and caches. These toolbar buttons include actions such as starting, stopping or pausing the simulation. From here, for example, you might choose to play your results straight through, or perhaps, just calculate a single step of the simulation. For additional information on options that affect your simulation, see the Snapshot section in FumeFX Preferences.





FumeFX offers several simulation modes.


Default - This mode lets you to simulate a default grid which can be further refined in Wavelet mode or slowed down with Post Processing.


Initial State - This button starts the simulation from a snapshot - a selected frame of the simulation, whose initial conditions were previously saved to a simulation file (.fdc) or output file (.fxd). The file can be selected from the Floater Menu > File > Load initial state. If it hasn`t been selected yet, a file selection dialog box will open, prompting you to select it.

If you are using an .fxd file for the initial state make sure that such a file contains velocity channel.


Wavelet - To be able to use this mode, you need to have caches prepared by using Default simulation mode first. This mode will reload the Default caches, upscale simulation grid and use saved information to create additional detail.


Post - Post mode allows you to retime and optimize caches created in Default or Wavelet modes. Caches optimization allows excluding of channels that are no longer needed. This can be very useful for building .fxd caches with minimum data needed for rendering. Second option is to optimize grid dimensions which will result in a tightest possible container around smoke/fire. Using these methods, both file sizes and memory requirements can significantly decrease, so you can expect faster rendering times.


Start/Stop - Select this button to run a simulation from the Start Frame to the End Frame (parameters that are available inside the General Tab > Output Rollout). Throughout this simulation, an active GPU viewport will show the most recently calculated frame. Note that during the simulation, FumeFX will not block user interface. While FumeFX is running a simulation, you can change simulation parameters or even source and object parameters. However, you will not be able to render, change simulation type, change Extra Detail mode or change input cache.

In Simulation Loop mode parameters such as Grid Dimension, Exporting Channels and Simulate Smoke/Fuel are updated when simulation starts over. Once the simulation is running, click on this button to stop the simulation.


Note: Depending on the selected cache, Stop and Continue buttons will be enabled or disabled. For example, when Wavelet cache is selected it is not possible to start Wavelet Simulation.


Pause - Simulation can be paused in any given moment.


Cancel - During the simulation click this button to initiate immediate simulation Cancel. No stop/continue data will be saved.


Continue - You can use this button to continue a simulation in several ways - right click on it for more options.

  • from the point at which it had been stopped with the Stop button
  • from any snapshots that you have specified in the Snapshot options under Preferences; right-click for a pop-up list of available snapshots to continue from. If snapshots were created with different grid parameters, you will be able to select Show same grid settings only, which will limit the selection range to matching files.
  • from any .fxd cache that has already been calculated, provided that the velocity channel was exported. To continue from the current frame output; the position of the 3ds Max time slider indicates continuing point, right click on this button and select "Current Frame Output".





Stopping and continuing a simulation from a snapshot file (.fdc) will give you the exact same results as running a simulation uninterrupted. You can also continue from output files; however, since pressure is not saved in output files (.fxd), a slight difference will be introduced into the following frames. This difference will be evident in explosion effects.


In the events when simulation has reached the grid boundary and you needed it to expand even further, FumeFX allows you to change the grid dimensions and continue simulation from previous frame that has been calculated. This feature works only with adaptive grid.


Run simulation through BackBurner - This is a toggle button. When on, user can assign BackBurner jobs and FumeFX will run simulation before the first render begins.


You can use the BackBurner option to start a Default simulation, Initial State Simulation, Wavelet Turbulence simulation and Retimer simulations. It is not possible to continue a simulation through BackBurner.






Lets you to choose which cache will be loaded. If you select a cache that isn`t present an error will show up.


Note: Depending on the selected cache, Stop and Continue buttons will be enabled or disabled. For example, when Wavelet cache is selected it is not possible to start Wavelet Simulation.


Draft Mode - When enabled, FumeFX will load caches at reduced resolution for viewport. This is very useful when you`re working on shader adjustments or test renderings.


Read Only Mode - Caches are temporarily in read-only mode and they cannot be overwritten from the FumeFX UI. You can still delete them from the Windows Explorer.


Select Caches - Allows you to select caches to be loaded. Right click for more options.


Delete Caches - Clicking on this icon will delete all the related caches.