Curl Noise particle node

Turns this node on and off. The node is only active if this value is greater than 0. This is useful to control the effect of this node with an expression.

Note that this is activation of the node as a whole. You can’t use this parameter to deactivate the node for certain particles.

Only affect a group of points (created with, for example, a Group POP or Collision POP) out of all the points in the input.

Specifies the noise type.

Allows the noise field to be effectively moved through space.

The scale of the noise. Decreasing frequency increases feature size.

Controls the resolution of the curl function used to generate the noise. A lower value will lead to tighter spirals in the noise.

Maximum value of noise field.

Raises the noise to the given exponent.

Number of iterations of fractal noise to add.

Scale of noise added with each iteration.

A volume that is a signed distance field used for collision calculations. The turbulence is damped near the collision object to prevent particles from passing through.

When particles cross the SDF boundary they have their velocities reversed according to the SDF normal and are pushed outside of the SDF.

The distance at which the particles start to slow down due to a collision object.

There are several different ways to update a particle system in response to an external velocity field. They are broadly categorized as Force, Velocity, and Position updates.

The Force Update will adjust the acceleration of the particles according to their mass, the force scale, and the velocity field. This acts like the Force POP.

Blend Velocity directly changes the velocity of the particles by blending in the velocity field causing them to swiftly match the velocity field.

Position Update directly moves the velocity positions. This is useful as it allows the particles own velocity to be considered independently of the bulk fluid velocity. Position Update is similar to what the Gas Advect DOP would perform.

Scales the force for force update.

Treats all particles as having unit mass, ignoring any mass attribute.

Ignore the mass attribute and use the specified mass.

The mass to use if mass is overridden.

Instead of applying a force in the direction of the velocity field, the force is applied relative to the difference between the particle’s velocity and the velocity field. This effectively adds an implicit drag that causes the particles to match the velocity field.

In Velocity Blend mode, the amount to mix in the field velocity every timestep.

In Velocity Blend mode, the amount to add the curlnoise velocity to the particle’s velocity. This can be useful in addition to advectbyvolume to layer turbulence on a velocity field.

In Position Update mode it is possible to read in the velocity from the velocity field. Note that the resulting velocity will be used by the particle integrator, so unless something special is done this could result in double-moving the particle.

The number of threads to create to process the VEX commands. If you have multiple processors, this can speed up processing of the node.