Fluid Liquid attributes

Enable Liquid Simulation

When on, you can use the Liquids attributes to create fluid effects simulations that look and behave like real liquids.

For more information about liquid simulations, see also Liquid simulation setup.

Liquid Method

Specifies the liquid simulation method used for liquid effects.

Liquid and Air

The fluid uses a solving method that differentiates the density of air and water in the fluid. The fluid solver treats the liquid density as an incompressible fluid, while the air is fully compressible.

A Liquid Min Density attribute lets you specify the density value at which the solver considers the fluid a liquid. For example, at the default value of 0.5, areas of the fluid with density values of 0.5 or greater simulate as an incompressible liquid, while areas that have density of less than 0.5 simulate as air. When Liquid Min Density is set to 0, there is no differentiation between air and water, causing the fluid to behave as a fully incompressible fluid. See Liquid Min Density.

This simulation method works best when the Solver Quality is set to a high value and Forward Advection is on. Use Replace emission type to maintain a single, continuous volume of fluid. You can use Density Tension to generate realistic surface tension in the fluid.

Density Based Mass

The fluid uses a solving method that varies mass according to fluid density. Areas of low density remain incompressible and apply an outward force to denser regions.

Using the Mass Range attribute, you can specify the relationship between mass and fluid density. For example, setting Mass Range to a high value makes the dense regions of the fluid heavier than areas with no density. See Mass Range.

You can use this method to simulate the interaction of two substances with different densities, such as oil and water, as well as simulate gas bubbles moving through a liquid.

This simulation method works best when the Forward Advection is on. Use Replace emission type to maintain a single, continuous volume of fluid.

Liquid Min Density

Specifies the density value at which the solver differentiates between liquid and air when the Liquid and Air simulation method is used. Liquid densities are calculated as incompressible fluids while air is fully compressible. At a value of 0 the solver does not differentiate between liquid and air and treats all fluid as incompressible, making it behaves as a single fluid.

Liquid Mist Fall

Applies a downward force to areas in the fluid that have density lower than the value specified by the Liquid Min Density value. At a value of 0, no force is applied. Increasing Liquid Mist Fall increases the strength of the downward force.

The force applied by Liquid Mist Fall is not the same as the Gravity force that is applied to the density grid. Liquid Mist Fall is useful for generating spray and mist effects for liquids or ensuring that there is no mist in your liquid effect.

Mass Range

Defines the relationship between mass and fluid density when the Density Based Mass simulation method is used. At higher Mass Range values, dense regions in the fluid are much heavier than low density regions, simulating a relationship similar to air and water.

Density Tension

Density Tension pushes density into round shapes, making the density boundaries more defined in the fluid. When set to high values, Density Tension can force fluid density into individual clusters on the grid. The effect of Density Tension in a fluid effect is similar to the effect of surface tension in liquids. Density Tension does not affect the velocity in voxels.

In some cases, Density Tension can be used to remove artifacts that appear when using High Detail Solve.

Density Tension is the same attribute as the Tension attribute and can be used with the default fluid solver when Enable Liquid Simulation is off. It has been added to the Liquids attribute section for user convenience.

Tension Force

Applies a force that simulates surface tension based on the density in the grid. Tension Force is similar to Density Tension, but rather than modifying density values, Tension Force modifies momentum by adding small amounts of velocity in the fluid.

You can use Tension Force with Density Tension to create realistic surface tension in your liquid effect. Tension Force can be used with the default fluid solver when Enable Liquid Simulation is off.

Density Pressure

Applies an outward force to counter the compression affect that Forward Advection can apply to fluid density, particularly along container boundaries. In this way, the attribute attempts to conserve the overall fluid volume ensuring no density loss. For example, in a water tank simulation, fluid may appear to collapse or drain without sufficient Density Pressure.

Density Pressure is the same attribute as the Pressure attribute that is located in the Density section of the Contents Details attributes. Density Pressure can be used with the default fluid solver when Enable Liquid Simulation is off. It has been added to the Liquids attribute section for user convenience.

Density Pressure Threshold

Specifies the density value at which Density Pressure is applied on a per voxel-basis. For voxels that have density lower than Density Pressure Threshold, no Density Pressure in applied.

Density Pressure Threshold has the same effect as the Pressure Threshold attribute that is located in the Density section of the Contents Details attributes. Density Pressure Threshold can be used with the default fluid solver method when Enable Liquid Simulation is off.