Enables density control for whitewater particles.

Particles in this range will be subjected to density control.

Stiffness of the density constraints, controlling how harshly deviations from target density are penalized.

Enable variable enforcement of the density constraints at different liquid depths.

Controls the stiffness of density constraints at different liquid depths. Note that if an endpoint of this ramp evaluates to a non-zero value, then all particles beyond that end will also be subjected to density control.

Desired number of points in each particle’s neighborhood.

Range of allowed kernel radii, as multiples of a global radius.

The number of points in a whitewater particle’s neighborhood is not allowed to exceed this value.

This fraction of all particles that are eligible for density control will actually be used. Reducing Inclusion Chance will decrease running times, but may degrade quality.

Number of times to repeat constraint projection for each particle.

The maximum acceleration that can be applied to a particle by constraints.

Particles apply repulsive forces on their neighbors to prevent clustering. This parameter determines the distance (as a fraction of the particle’s kernel radius) at which this force is equal to Tensile Strength.

Magnitude of the repulsive forces between nearby particles.

Enabling viscosity causes velocity diffusion, resulting in more coherent motion among nearby whitewater particles.

Counteracts energy dissipation by maintaining vortices.

Enabling this feature preserves foam in denser areas and erodes it in sparser regions.

Particles within this distance of the liquid surface will be subjected to erosion.

Strength of erosion in less dense foam areas. Higher values for this parameter will result in more rapid disappearance of foam.

Controls the density range at which whitewater is protected from erosion.

Create and maintain repellant particles that push whitewater away and give rise to a cellular foam structure. These particles are contained in the object’s Repellants geometry.

Range of repellant sizes (stored in the radius point attribute).

Range of repellant strengths (stored in the magnitude point attribute).

Range of values for the repellants' noise point attribute. This attribute controls the shape of each repellant, with 0 being perfectly circular and 1 being maximally “noisy”.

Range of values for the repellants' pulse point attribute. This attribute controls how fast the shape of a “noisy” repellant evolves.

When enabled, repellants will age and die once their life is up. The lifespan for a repellant is randomly selected from the provided range.

Enabling this option limits seeding of repellants to areas that already contain whitewater. A region is considered eligible for seeding if relative whitewater density is above the specified threshold.

Seed that controls random repellant seeding.

When this option is enabled, distribution of repellant sizes matches the given Radius Distribution; otherwise, size distribution is uniform.

When enabled, repellant strengths are attenuated based on liquid’s speed. With default settings, for example, repellants will be active only in slow regions.

Horizontal axis of Repulsion by Speed corresponds to this range.

A multiplier applied to the repellant strengths based on the underlying liquid’s speed.

When enabled, repellant strengths are attenuated based on liquid’s acceleration. With default settings, for example, repellants will be inactive in regions that are rapidly accelerating.

Horizontal axis of Repulsion by Acceleration corresponds to this range.

A multiplier applied to the repellant strengths based on the underlying liquid’s acceleration.

A multiplier applied to the repulsion force based on whitewater particle’s depth.

Enable a depth control mechanism to keep foam attached to the fluid surface.

When this option is enabled, adhesion is only applied to particles on the liquid’s upper surface, as determined by the direction of gravity. Turning this feature on reduces foam sticking to the bottom or sides of the domain.

Particles within this distance of the liquid surface will be subjected to depth control.

Depth control is disabled for particles that are within this distance of the collision geometry. To use this feature, the Collision SOP must be specified.

Depth control is disabled for particles if the angle between their velocity vector and surface normal is no larger than this value.

The maximum acceleration that can be applied to particles in an effort to keep them attached to the surface.

Controls how strictly depth control will be enforced at different depths. Lower stiffness values give rise to thicker foam.