General Parameters
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.
Allow Shrinking - Most of the time you will want grid to shrink and to occupy minimum required space for the simulation. However, if grid expands and shrinks during the simulation it will also delete velocity field which is very important to achieve natural rolling motion.
Extra Padding - Allowing velocity field to develop throughout the grid volume is of utmost importance for creating naturally moving fluid. When adaptive grid sensitivity is set to fields (smoke, fire...) adaptive grid will be created very tightly around smoke or any other field. Use this option to add extra voxels around the fields so that velocities can develop more naturally.
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.
Include Pressure - Enable this option if you want grid to expand based on pressure from the burning process and additional pressure introduced from sources.
Field Threshold - This parameter defines boundary sensitivity to smoke, fuel, fire and temperature. Larger number will generate tighter adaptive grid. If there is a source that doesn`t emit any matter and just produces velocities, use sensitivity by Velocity + Fields to be able to enlarge the grid.
Velocity Threshold - When Adaptive option is enabled and Sensitivity is set to Velocity + Fields, this parameter will define boundary sensitivity to velocity magnitude. Larger number will generate tighter adaptive grid. A good starting value would be grid Spacing area divided by a factor of 10.
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.