Enter the frame when the source/sink should be active and contribute to the simulation. You can animate this parameter to turn a source/sink on or off on demand.

You can choose whether the connected object should be a source to create particles or a sink to remove particles.

You can choose from three methods. Each method has its own set of parameters to control the sourcing or sinking process.

Particles are emitted in direction of the source object’s normals with the given pressure. If you fill an object with Uniform Pressure, sourcing stops once the given pressure value is reached. Pressure-based sourcing often creates very fast particles. Animate the parameter to tame the particles. When in sink mode, Uniform Pressure is set to -1 to create a suction effect towards the connected geometry. The higher the value, the stronger the suction effect. With positve values, you can observe a repulsion effect before the particles are finally deleted.

Particles are emitted in direction of the source object’s normals with the given pressure. If you fill an object with Hydrostatic Pressure, sourcing stops once the adjusted Water Level is reached. Pressure-based sourcing often creates very fast particles. Animate the parameter to tame the particles. Although the parameter accepts any positive value, we recommend using values between 0 and 1. Hydrostatic Pressure is currently limited. Imagine a water hose with a nozzle. In the real world you can control the pressure inside the hose by closing or opening the nozzle. As a result, the velocity of water, leaving the hose, changes accordingly. This dynamic interplay between pressure and velocity is not possible with SOP particle fluids. Hydrostatic Pressure can also be used in sink mode and negative values create a suction effect. In sink mode there is hardly any difference between Hydrostatic Pressure and Uniform Pressure.

This parameter is only avaiable in conjunction with Hydrostatic Pressure and defines a threshold. Once the water level has reached the given value, sourcing stops. This method can be used to fill a glass or a pool, for example.

By default, the water’s baseline is at 0,0,0. Water Origin shifts this baseline by adding an offset. In most cases you only change the Y direction. Imagine you fill a pool to a Water Level of 1, but the pool’s bottom is at 0.2. In this case, the effective fill level is 1.0 - 0.2 = 0.8. To compensate for this difference, set the Y value of Water Origin to 0.2.

The default value is good for most simulations. Higher values shrink the source volume and decrease the amount of sourced water.

You can give the fluid particles an initial velocity and direction by defining a vector. If other velocities are invloved, e.g. Normal Velocity, then Additional Velocity is added. In sink mode, Aditional Velocity can be used to define a direction in which the particles are attracted, e.g. only along the Y or the negative Z axis. With negative values it’s possible to flip directions.

When Compute Velocity From Deformation is turned on, the velocity of animated and deforming objects can be scaled with this factor.

When turned on, particles are emitted in direction of the source object’s normals with the given speed. In sink mode, negative values create a suction effect towards the connected sink geometry. Higher values create a stronger suction. With positive settings you can observe a repulsion effect before the particles are finally deleted.

You can turn on this option to take the velocity of animated and deformed objects into account. Increase or decrease this velocity with the Scale Velocity factor.