This group only appears when Advanced mode is selected.
- Evaluate Neighbor Tile
- When enabled, self-collision and volume preservation calculations use foam particles in neighboring tiles. This increases simulation accuracy and eliminates visible boundary artifacts between tiles, especially with thick, static foam. Enabling Evaluate Neighbor Tile increases simulation time.
Note: You must set the Preserve Volume option to a non-zero value to compute this option.
- Compression Model
- Enables the Compression Model solver method. Similar to smoothed-particle hydrodynamics (SPH), Compression Model uses incompressibility calculations to resolve overlapping foam particles.
This method increases accuracy and realism of foam simulations in small-scale liquids. When the combined particle overlap density is less than the set Target Density value, particles attract each other. When the particle overlap density is greater than the set the Target Density option however, foam particles repel each other.
- Target Density
- Controls how the computations of the Compression Model method are applied to the foam simulation. Increasing this value allows more particles to overlap before they repel each other. For typical foam simulations, use values between 0 and 2.
Values such as 10 can provide smoother distribution of particles. When using higher values, the Point Radius needs to be increased to compensate for the higher particle overlap density. This results in greater accuracy at the cost of longer computation.
- Inherit Liquid Velocity
- Applies acceleration to the emitted foam particles based on the liquid velocity. When set to 1, foam particles emit with a velocity equal to the liquid velocity vector. At values greater than 1, foam can shoot off the surface as spray; values of less than 1 will dampen the particle velocity.
- Gravity Multiplier
- Sets a value that scales the liquid container's Gravity Magnitude and applies it to the foam particles.
- Mask Falloff Distance
- Sets a falloff region, in scene units, around the input mesh of a foam mask. Increase this value to soften the emission boundaries around mask.
- Dissipation Rate
- Sets the rate per-second that foam particles lose density. Foam particles at and above the liquid surface will dissipate. Particles under the liquid surface do not dissipate.
- Kill Density Threshold
- Sets the Threshold Density value causing foam particles to be eliminated.
Particles below the surface of the liquid have a density of 1 plus the Max Liquid Depth value. At the surface particles have a density of 1; above the surface they have a density of less than 1.
- Buoyancy
- Sets the upward acceleration of foam particles in m/s2.
With turbulent, fast moving liquids, increase Buoyancy to force particles to the surface. This stops the particles from remaining under the surface as bubbles, which do not dissipate.
- Collider Kill Depth
- Sets the distance from collision objects, in voxels, that triggers an additional dissipation effect on colliding particles.
This is useful for eliminating particles that are trapped by collision objects and cannot rise to the liquid surface and dissipate. When set to 1, colliding particles dissipate at the set Dissipation Rate. When set to 0 or a negative value, particles dissipate at a rate greater than the Dissipation Rate. The relation between Collide Kill Depth and dissipation rate is non-linear. For example, when set to -0.5, dissipation increases by a factor of 10. Values greater than 1 do not noticeably affect dissipation as collisions stop particles from penetrating more that 1 voxel inside the collision object.
- Surface Tension
- Sets the amount of surface tension to apply to the foam particles. The attractive force pulling particles together works within the region set by Tension Radius. Use values between 0 and 0.1, and more typically in the 0.01 to 0.02 range. Values higher than 0.1 can cause foam particles to ball together. The effect is most noticeable in small-scale non-turbulent liquids. Foam Surface Tension works best with Compression Model and Evaluate Neighbor Tile turned on.
Note: You must set the Preserve Volume option to a non-zero value to compute this option.
- Tension Radius
- Sets the active distance of Surface Tension in voxels. This distance is computed as a multiple of the Point Radius option, where a value of 2 corresponds to a distance that is two times the point radius.