Liquid Parameters

Presets group

Presets

Loads, saves, and deletes preset liquid parameters. The list includes the following presets: beer, blood, caramel, cream, honey, ketchup, latex paint, maple syrup, mercury, milk, motor oil, olive oil, orange juice, putty, silicone, tooth paste, transmission fluid, and water.

Click to load the currently selected preset from the drop-down list. Click to save the current settings under a new preset name, and click to delete the selected preset.

Note: You cannot delete any of the provided presets.

Droplet group

Droplets are particles that break away from the main body of liquid in a simulation. There are several uses for droplets:

• Breaking up splashes and sheets to create a more spray-like effect.
• Reducing memory use and computation caused by particles that separate from the main liquid body. Droplets require simpler calculations involving ballistic motion rather than liquid dynamics.
• Corrects visual problems such as bumps and dimples in the liquid surface caused by particles rejoining the main body too soon.

Threshold

Sets the threshold at which particles get converted to droplets. Lower values create more droplets, breaking up sheets and tendrils more quickly. To prevent droplets, set the threshold to 1.0 or higher.

Mergeback Depth

Sets the depth (in voxel widths) within the liquid surface that a droplet must reach before it rejoins the liquid and is included in fluid dynamic computations. This setting can reduce bumps and dimples in the liquid surface caused by particles rejoining the main body too soon.

Particle Distribution group

This group controls the number of particles per voxel at the surface and in the interior of liquids, as well as the depth of the surface layer. In general more particles allow for more detail at the expense of higher memory requirements and slower computations. Typically fewer particles are needed in interior voxels than at the surface because the surface is what gets rendered or meshed.

Surface Bandwidth

Sets the width of the liquid's surface in voxels.

Interior Particle Density

Sets the particle density throughout the inner volume of the liquid.

Surface Particle Density

Sets the particle density at the surface of the liquid. You can use this to generate a denser particle distribution with more detail at the liquid surface, without extra particles where detail is not needed in the interior. Do not use a value less than 1.0.

Tip: If you experience excess volume especially in very splashy simulations, set both Interior Particle Density and Surface Particle Density to 1.0.

Vorticity group

Enable

Enables the Vorticity channel calculations. This is the accumulation of rotation magnitude within voxels. The vorticity can be used to simulate churning.

Decay

Sets a value that is subtracted from the accumulated vorticity every frame.

Multiplier

Sets a multiplier for the magnitude of the curl of the current frame before it is added to the accumulated vorticity.

Maximum

Sets a clamp for the total vorticity.

Surface Tension group

Enable

Enables surface tension.

Surface Tension

Increases the attraction force between liquid particles, causing more of a clumping effect.

Viscosity group

Viscosity

Controls the thickness of a fluid. For example, water has a low viscosity (approximately 0.001) while honey has a high viscosity. Using a value of 0.0 for water avoids unnecessary computation.

Scale

Smooths and dampens liquid flow by blending the simulated velocities with the neighborhood average. This is not physically correct but can be used to mimic viscosity at very little computational cost compared to using the Viscosity setting. Values over 2.0 may produce unpredictable results over the duration of your simulation.

Erosion group

Factor

Controls how closely the fluid boundary gets shrink-wrapped back to the particle positions. A value of 0.0 results in no erosion while 1.0 erodes by the full particle radius.

Factor Near Solids

Determines whether the fluid surface is eroded in regions that are close to collider objects based on the normal of the collider surface. Note that wherever the surface is eroded, it is always eroded by the full Factor amount.