The General Parameters rollout affects the basic parameters of your simulation area. In other words, this rollout defines the parameters of the FumeFX Grid. This group of controls is also available in the FumeFX Modify Panel.
Spacing - This parameter directly affects the detail level in your simulation. Type in or use the spinner to set the spacing of the voxel-based grid. The chosen value defines voxel size; smaller voxel size allows for more voxels in simulation, which produces greater detail.
Width, Length, Height - These three values set the volumetric dimensions of the FumeFX Grid, thereby establishing the boundaries for simulation within the scene.
Adaptive - While enabled, the grid will expand and shrink with the movement or absence of fluid to use only the necessary portion of the overall grid space. It is highly recommended to leave this enabled because it reduces simulation time and file size.
Boundless - This option allows you to select grid axes that will be allowed to expand beyond the boundaries set by the container shape. Keep in mind that grid expansion will be limited by the amount of available computer memory.
Sensitivity - FumeFX allows you to choose between different modes that will allow it to adjust grid size based on values near to the adaptive grid boundary.
Threshold - When the Adaptive option is enabled, this parameter defines the boundary's sensitivity to the production of smoke/fuel/fire. The larger the number, the tighter the adaptive box. Leave this value between 0.1 and 0.01.
If there is a source that does not emit any matter, but just produces wind, and you want FumeFX to enlarge grid accordingly to the wind strength, set the Sensitivity value