# Vortex Force dynamics node

Applies a vortex-like force on objects, causing them to orbit about an axis along a circular path.

The Vortex Force DOP applies a vortex-like force on objects, causing them to orbit around a curve. They are great for creating tornado like effects.

Vortex Forces work well with FLIP fluid simulations. All you need to prepare ahead of time is an open curve that will be the center spine for the vortex.

Geometry data defining the orbits must be attached to this DOP as subdata. The geometry should consist of a single open curve, defining the central axis of the vortex.

The Vortex Force will define a number of circular orbiting paths around this axis, and at each time step, the force will try to push an object to the closest orbiting path. The number of different orbiting paths along the axis is determined by the Density parameter. The position of the axis can be controlled by attaching a Position DOP as subdata.

The geometry must define two point attributes: one representing the radius of the circular orbit, and another defining the orbiting velocity. There are also a number of optional attributes, providing more control over the vortex behavior.

You can add noise to the force applied by this DOP by connecting a Noise DOP to the second input of this node, which adds the noise as subdata of the force data.

## Data Options

The radius of the circular orbiting path around the axis is determined by a point attribute on the axis geometry.

This parameter controls the name of that point attribute.

Orbital Velocity Attribute

The orbital speed around the axis is determined by a point attribute on the axis geometry.

This parameter controls the name of that point attribute. The units of the attribute are determined by the Orbital Velocity Type parameter.

Orbital Velocity Type

The interpretation of the Orbital Velocity Attribute on the axis geometry is determined by this parameter.

Tangential Velocity

The orbital velocity attribute is a linear velocity, measured in meters per second (m/s).

Angular Velocity

The orbital velocity attribute is an angular velocity, measured in degrees per second (deg/s).

Orbital Direction Attribute

By default, the circular orbiting paths are in planes perpendicular to the axis geometry. (This default behavior can be further controlled using the Polyline Orbital Direction parameter.)

If the point attribute defined by this parameter is present, however, it is used to define the normal of the circular orbiting plane.

Polyline Orbital Direction

When the Orbital Direction Attribute parameter is not being used, the circular orbiting paths are in planes perpendicular to the axis geometry.

This parameter controls how "perpendicular" is determined from the axis geometry. First, the closest segment on the axis is found, and then the slope at either its previous or next vertex is used to define the orbital plane.

Use Next Vertex

Use the slope at the next vertex to define the orbital plane.

Use Previous Vertex

Use the slope at the previous vertex to define the orbital plane.

Use Both Vertices

Average the slopes at the next and previous vertices to define the orbital plane.

Max Distance Attribute

By default, the vortex force acts on all objects, but it can be limited to only act on objects within a limited range.

This is done by creating a point attribute defining the threshold for action. (A value of -1 can be used to represent an infinite distance.) This parameter controls the name of that attribute.

Lift Force Attribute

By default, the vortex force acts in the plane perpendicular to the axis, and does not cause movement parallel to the axis. A special "lift force" can optionally be applied to move objects along the axis.

The lift force only acts within a limited radius, and can have a falloff. This parameter defines the name of a point attribute determining the strength of the lift force.

The lift force only acts within a limited distance from the axis. By default (when this parameter is set to one), it only acts inside the orbital paths.

Setting this parameter to a value greater than one will allow the lift force to act at greater distances, while a value smaller than one will limit it to a smaller distance.

Lift Force Falloff

This parameter determines how much the lift force decreases as objects get further from the central axis.

A value of one indicates no falloff, while higher values correspond to higher falloffs.

Orbital Density

This controls how many orbiting paths are defined along the axis.

High values create more paths, possibly through interpolation, and can be useful if the axis has a complicated shape.

Drag Constant

A value that determines how fast the object converges to desired orbital velocity.

Sampling Mode

Indicates the preferred sampling level (point, circle, or sphere) to trade accuracy for efficiency of the computation.

## Guide Options

Show Guide Geometry

When turned on, the orbital paths are displayed.

Control Orbits Color

The color of the control orbital paths.

Interpolated Orbits Color

The color of the interpolated orbital paths.

Orbit Divisions

Use a polygon with this number of sides as guide geometry for a single orbit.

Show Max Orbits

When turned on, the orbits that define the maximum distances are also displayed.

Sampling Mode

Controls how the force is sampled over space. The behavior will vary depending on the solver. Fluid solvers will always sample per-voxel, but RBD solvers can switch between sampling only the centroid, only the surface, or the entire volume.

Default

Each force type has its own idea of the optimal sampling mode. For uniform forces, for example, only one sample is taken, the equivalent of Point. But with a Field Force that is expected to vary over space, the Sphere sampling mode is the default when Treat as Wind is false, otherwise the Circle sampling mode is used.

Point

Perform a single force evaluation at the center of the object, treating this one value as a constant force for the object. This is the most efficient approach but does not allow for any nuances, for example, of an off-center fan causing an object to start spinning.

Circle

Perform a force evaluation on the surface of the object. This is useful for forces such as wind that one wants to apply non-uniformally depending on the orientation of the object.

Sphere

Perform a force evaluation throughout the volume of the object. This is useful for forces which you want to respect the shape of the object. The number of samples is proportional to the SDF resolution of RBD Objects, however, so can get very expensive.

Parameter Operations

Each data option parameter has an associated menu which specifies how that parameter operates.

Use Default

Use the value from the Default Operation menu.

Set Initial

Set the value of this parameter only when this data is created. On all subsequent timesteps, the value of this parameter is not altered. This is useful for setting up initial conditions like position and velocity.

Set Always

Always set the value of this parameter. This is useful when specific keyframed values are required over time. This could be used to keyframe the position of an object over time, or to cause the geometry from a SOP to be refetched at each timestep if the geometry is deforming.

You can also use this setting in conjunction with the local variables for a parameter value to modify a value over time. For example, in the X Position, an expression like `\$tx + 0.1` would cause the object to move 0.1 units to the right on each timestep.

Set Never

Do not ever set the value of this parameter. This option is most useful when using this node to modify an existing piece of data connected through the first input.

For example, an RBD State DOP may want to animate just the mass of an object, and nothing else. The Set Never option could be used on all parameters except for Mass, which would use Set Always.

Default Operation

For any parameters with their Operation menu set to Use Default, this parameter controls what operation is used.

This parameter has the same menu options and meanings as the Parameter Operations menus, but without the Use Default choice.

Data Sharing

Controls the way in which the data created by this node is shared among multiple objects in the simulation.

Data sharing can greatly reduce the memory footprint of a simulation, but at the expense of requiring all objects to have exactly the same data associated with them.

Do Not Share Data

No data sharing is used. Each object has its own copy of the data attached.

This is appropriate for situations where the data needs to be customized on a per-object basis, such as setting up initial positions and velocities for objects.

Share Data Across All Time

This node only creates a single piece of data for the whole simulation. This data is created the first time it is needed, so any expressions will be evaluated only for the first object.

All subsequent objects will have the data attached with the same values that were calculated from the expressions for the first object. It is important to note that expressions are not stored with the data, so they cannot be evaluated after the data is created.

Expressions are evaluated by the DOP node before creating the data. Expressions involving time will also only be evaluated when this single piece of data is created. This option is appropriate for data that does not change over time, and is the same for all objects, such as a Gravity DOP.

Share Data In One Timestep

A new piece of data is created for each timestep in the simulation. Within a timestep though, all objects have the same data attached to them. So expressions involving time will cause this data to animate over time, but expressions involving the object will only evaluate for the first object to which the data is attached.

This option is appropriate for data that changes over time, but is the same for all objects such as a Fan Force DOP, where the fan may move or rotate over time.

Activation

Determines if this node should do anything on a given timestep and for a particular object. If this parameter is an expression, it is evaluated for each object (even if data sharing is turned on).

If it evaluates to a non-zero value, then the data is attached to that object. If it evaluates to zero, no data is attached, and data previously attached by this node is removed.

Group

When an object connector is attached to the first input of this node, this parameter can be used to choose a subset of those objects to be affected by this node.

Data Name

Indicates the name that should be used to attach the data to an object or other piece of data. If the Data Name contains a "/" (or several), that indicates traversing inside subdata.

For example, if the Fan Force DOP has the default Data Name "Forces/Fan". This attaches the data with the name "Fan" to an existing piece of data named "Forces". If no data named "Forces" exists, a simple piece of container data is created to hold the "Fan" subdata.

Different pieces of data have different requirements on what names should be used for them. Except in very rare situations, the default value should be used. Some exceptions are described with particular pieces of data or with solvers that make use of some particular type of data.

Unique Data Name

Turning on this parameter modifies the Data Name parameter value to ensure that the data created by this node is attached with a unique name so it will not overwrite any existing data.

With this parameter turned off, attaching two pieces of data with the same name will cause the second one to replace the first. There are situations where each type of behavior is desirable.

If an object needs to have several Fan Forces blowing on it, it is much easier to use the Unique Data Name feature to ensure that each fan does not overwrite a previous fan rather than trying to change the Data Name of each fan individually to avoid conflicts.

On the other hand, if an object is known to have RBD State data already attached to it, leaving this option turned off will allow some new RBD State data to overwrite the existing data.

## Inputs

First Input

This optional input can be used to control which simulation objects are modified by this node. Any objects connected through this input and which match the Group parameter field will be modified.

If this input is not connected, this node can be used in conjunction with an Apply Data node, or can be used as an input to another data node.

All Other Inputs

If this node has more input connectors, other data nodes can be attached to act as modifiers for the data created by this node.

The specific types of subdata that are meaningful vary from node to node. Click an input connector to see a list of available data nodes that can be meaningfully attached.

## Outputs

First Output

The operation of this output depends on what inputs are connected to this node. If an object stream is input to this node, the output is also an object stream containing the same objects as the input (but with the data from this node attached).

If no object stream is connected to this node, the output is a data output. This data output can be connected to an Apply Data DOP, or connected directly to a data input of another data node, to attach the data from this node to an object or another piece of data.

## Locals

channelname

This DOP node defines a local variable for each channel and parameter on the Data Options page, with the same name as the channel. So for example, the node may have channels for Position (positionx, positiony, positionz) and a parameter for an object name (objectname).

Then there will also be local variables with the names positionx, positiony, positionz, and objectname. These variables will evaluate to the previous value for that parameter.

This previous value is always stored as part of the data attached to the object being processed. This is essentially a shortcut for a dopfield expression like:

```dopfield(\$DOPNET, \$OBJID, dataName, "Options", 0, channelname)
```

If the data does not already exist, then a value of zero or an empty string will be returned.

DATACT

This value is the simulation time (see variable ST) at which the current data was created. This value may not be the same as the current simulation time if this node is modifying existing data, rather than creating new data.

DATACF

This value is the simulation frame (see variable SF) at which the current data was created. This value may not be the same as the current simulation frame if this node is modifying existing data, rather than creating new data.

RELNAME

This value will be set only when data is being attached to a relationship (such as when Constraint Anchor DOP is connected to the second, third, of fourth inputs of a Constraint DOP).

In this case, this value is set to the name of the relationship the data to which the data is being attached.

RELOBJIDS

This value will be set only when data is being attached to a relationship (such as when Constraint Anchor DOP is connected to the second, third, of fourth inputs of a Constraint DOP).

In this case, this value is set to a string that is a space separated list of the object identifiers for all the Affected Objects of the relationship to which the data is being attached.

RELOBJNAMES

This value will be set only when data is being attached to a relationship (such as when Constraint Anchor DOP is connected to the second, third, of fourth inputs of a Constraint DOP).

In this case, this value is set to a string that is a space separated list of the names of all the Affected Objects of the relationship to which the data is being attached.

RELAFFOBJIDS

This value will be set only when data is being attached to a relationship (such as when Constraint Anchor DOP is connected to the second, third, of fourth inputs of a Constraint DOP).

In this case, this value is set to a string that is a space separated list of the object identifiers for all the Affector Objects of the relationship to which the data is being attached.

RELAFFOBJNAMES

This value will be set only when data is being attached to a relationship (such as when Constraint Anchor DOP is connected to the second, third, of fourth inputs of a Constraint DOP).

In this case, this value is set to a string that is a space separated list of the names of all the Affector Objects of the relationship to which the data is being attached.

ST

This value is the simulation time for which the node is being evaluated.

This value may not be equal to the current Houdini time represented by the variable T, depending on the settings of the DOP Network Offset Time and Time Scale parameters.

This value is guaranteed to have a value of zero at the start of a simulation, so when testing for the first timestep of a simulation, it is best to use a test like `\$ST == 0` rather than `\$T == 0` or `\$FF == 1`.

SF

This value is the simulation frame (or more accurately, the simulation time step number) for which the node is being evaluated.

This value may not be equal to the current Houdini frame number represented by the variable F, depending on the settings of the DOP Network parameters. Instead, this value is equal to the simulation time (ST) divided by the simulation timestep size (TIMESTEP).

TIMESTEP

This value is the size of a simulation timestep. This value is useful to scale values that are expressed in units per second, but are applied on each timestep.

SFPS

This value is the inverse of the TIMESTEP value. It is the number of timesteps per second of simulation time.

SNOBJ

This is the number of objects in the simulation. For nodes that create objects such as the Empty Object node, this value will increase for each object that is evaluated.

A good way to guarantee unique object names is to use an expression like `object_\$SNOBJ`.

NOBJ

This value is the number of objects that will be evaluated by the current node during this timestep. This value will often be different from SNOBJ, as many nodes do not process all the objects in a simulation.

This value may return 0 if the node does not process each object sequentially (such as the Group DOP).

OBJ

This value is the index of the specific object being processed by the node. This value will always run from zero to NOBJ-1 in a given timestep. This value does not identify the current object within the simulation like OBJID or OBJNAME, just the object’s position in the current order of processing.

This value is useful for generating a random number for each object, or simply splitting the objects into two or more groups to be processed in different ways. This value will be -1 if the node does not process objects sequentially (such as the Group DOP).

OBJID

This is the unique object identifier for the object being processed. Every object is assigned an integer value that is unique among all objects in the simulation for all time. Even if an object is deleted, its identifier is never reused.

The object identifier can always be used to uniquely identify a given object. This makes this variable very useful in situations where each object needs to be treated differently. It can be used to produce a unique random number for each object, for example.

This value is also the best way to look up information on an object using the dopfield expression function. This value will be -1 if the node does not process objects sequentially (such as the Group DOP).

ALLOBJIDS

This string contains a space separated list of the unique object identifiers for every object being processed by the current node.

ALLOBJNAMES

This string contains a space separated list of the names of every object being processed by the current node.

OBJCT

This value is the simulation time (see variable ST) at which the current object was created.

Therefore, to check if an object was created on the current timestep, the expression `\$ST == \$OBJCT` should always be used. This value will be zero if the node does not process objects sequentially (such as the Group DOP).

OBJCF

This value is the simulation frame (see variable SF) at which the current object was created.

This value is equivalent to using the dopsttoframe expression on the OBJCT variable. This value will be zero if the node does not process objects sequentially (such as the Group DOP).

OBJNAME

This is a string value containing the name of the object being processed.

Object names are not guaranteed to be unique within a simulation. However, if you name your objects carefully so that they are unique, the object name can be a much easier way to identify an object than the unique object identifier, OBJID.

The object name can also be used to treat a number of similar objects (with the same name) as a virtual group. If there are 20 objects named "myobject", specifying `strcmp(\$OBJNAME, "myobject") == 0` in the activation field of a DOP will cause that DOP to operate only on those 20 objects. This value will be the empty string if the node does not process objects sequentially (such as the Group DOP).

DOPNET

This is a string value containing the full path of the current DOP Network. This value is most useful in DOP subnet digital assets where you want to know the path to the DOP Network that contains the node.

## Examples

SimpleVortex Example for Vortex Force dynamics node

This example uses a few balls to visualize the force generated by a Vortex Force DOP.

# Dynamics nodes

• Marks a simulation object as active or passive.

• Creates affector relationships between groups of objects.

• Blends between a set of animation clips based on the agent’s turn rate.

• Layers additional animation clips onto an agent.

• Defines a target that an agent can turn its head to look at.

• Chooses an object/position for the head of an agent to look at.

• Moves the head of an agent to look at a target.

• Moves the head of an agent to look at a target.

• Adapts the legs of an agent to conform to terrain and prevent the feet from sliding.

• Project the agent/particle points onto the terrain

• Defines an orientation that aligns an axis in object space with a second axis defined by the relative locations of two positional anchors.

• Defines multiple points, specified by their number or group, on the given geometry of a simulation object.

• Defines orientations based on multiple points on the given geometry of a simulation object.

• Defines a position by looking at the position of a point on the geometry of a simulation object.

• Defines an orientation by looking at a point on the geometry of a simulation object.

• Defines a position by looking at the position of a point on the geometry of a simulation object.

• Defines an orientation by looking at a point on the geometry of a simulation object.

• Defines a position by looking at the position of a particular UV coordinate location on a primitive.

• Defines a position by specifying a position in the space of some simulation object.

• Defines an orientation by specifying a rotation in the space of some simulation object.

• Defines multiple attachment points on a polygonal surface of an object.

• Defines a position by specifying a position in world space.

• Defines an orientation by specifying a rotation in world space.

• Attaches data to simulation objects or other data.

• Creates relationships between simulation objects.

• Attaches the appropriate data for Bullet Objects to an object.

• Sets and configures an Bullet Dynamics solver.

• Applies a uniform force to objects submerged in a fluid.

• Attaches the appropriate data for Cloth Objects to an object.

• Defines the mass properties.

• Defines the physical material for a deformable surface.

• Defines the internal cloth forces.

• Creates a Cloth Object from SOP Geometry.

• Defines the plasticity properties.

• Constrains part of the boundary of a cloth object to the boundary of another cloth object.

• Defines how cloth uses target.

• Defines a way of resolving collisions involving a cloth object and DOPs objects with volumetric representations (RBD Objects, ground planes, etc.)

• Constrains an object to remain a certain distance from the constraint, and limits the object’s rotation.

• Constrains pairs of RBD objects together according to a polygon network.

• Defines a set of constraints based on geometry.

• Visualizes the constraints defined by constraint network geometry.

• Creates multiple copies of the input data.

• Sets and configures a Copy Data Solver.

• Mimics the information set by the Copy Object DOP.

• Defines a Crowd Fuzzy Logic

• Creates a crowd object with required agent attributes to be used in the crowd simulation.

• Updates agents according to their steer forces and animation clips.

• Defines a Crowd State

• Defines a transition between crowd states.

• Defines a Crowd Trigger

• Combines multiple crowd triggers to build a more complex trigger.

• Adds a data only once to an object, regardless of number of wires.

• Deletes both objects and data according to patterns.

• Applies force and torque to objects that resists their current direction of motion.

• Defines how the surrounding medium affects a soft body object.

• Dynamics nodes set up the conditions and rules for dynamics simulations.

• Controls Embedded Geometry that can be deformed along with the simulated geometry in a finite element simulation.

• Creates an Empty Data for holding custom information.

• Creates an Empty Object.

• Constrains points of a solid object or a hybrid object to points of another DOP object.

• Creates an FEM Hybrid Object from SOP Geometry.

• Constrains regions of a solid object or a hybrid object to another solid or hybrid object.

• Creates a simulated FEM solid from geometry.

• Constrains a set of points on a cloth object to the surface of a Static Object.

• Constrains an FEM object to a target trajectory using a hard constraint or soft constraint.

• Attaches the appropriate data for Particle Fluid Objects to become a FLIP based fluid.

• Evolves an object as a FLIP fluid object.

• Applies forces on the objects as if a cone-shaped fan were acting on them.

• Fetches a piece of data from a simulation object.

• Applies forces to an object using some piece of geometry as a vector field.

• Creates a vortex filament object from SOP Geometry.

• Evolves vortex filament geometry over time.

• Imports vortex filaments from a SOP network.

• Saves and loads simulation objects to external files.

• Allows a finite-element object to generate optional output attributes.

• Attaches the appropriate data for Fluid Objects to an object.

• Applies forces to resist the current motion of soft body objects relative to a fluid.

• Attaches the appropriate data for Fluid Objects to an object.

• A solver for Sign Distance Field (SDF) liquid simulations.

• A microsolver that adjusts an internal coordinate system attached to fluid particles in a particle fluid simulation.

• A microsolver that advects fields and geometry by a velocity field.

• A microsolver that advects fields and geometry by a velocity field using OpenCL acceleration.

• A microsolver that advects fields by a velocity field.

• A microsolver that computes analytic property of fields.

• A microsolver that swaps geometry attributes.

• A microsolver that blends the density of two fields.

• A microsolver that blurs fields.

• A microsolver that determines the collision field between the fluid field and any affector objects.

• A microsolver that builds a mask out of positive areas of the source fields.

• A microsolver that builds a mask for each voxel to show the presence or absence of relationships between objects.

• A microsolver that calculates an adhoc buoyancy force and updates a velocity field.

• A microsolver that performs general calculations on a pair of fields.

• A microsolver that detects collisions between particles and geometry.

• A microsolver that applies a combustion model to the simulation.

• A microsolver that adjusts an SDF according to surface markers.

• A microsolver that computes the cross product of two vector fields.

• A DOP node that creates forces generated from a curve.

• A microsolver that scales down velocity, damping motion.

• A microsolver that diffuses a field or point attribute.

• A microsolver that dissipates a field.

• Adds fine detail to a smoke simulation by applying "disturbance" forces to a velocity field.

• A microsolver that runs once for each matching data.

• A microsolver that embeds one fluid inside another.

• A microsolver that enforces boundary conditions on a field.

• A microsolver that equalizes the density of two fields.

• A microsolver that equalizes the volume of two fields.

• A microsolver that emits a DOP error.

• A microsolver that evaluates the external DOPs forces for each point in a velocity field and updates the velocity field accordingly.

• A microsolver that extrapolates a field’s value along an SDF.

• A microsolver that creates a feathered mask out of a field.

• A microsolver that calculates and applies feedback forces to collision geometry.

• A data node that fetches the fields needed to embed one fluid in another.

• Runs CVEX on a set of fields.

• Runs CVEX on a set of fields.

• A microsolver that copies the values of a field into a point attribute on geometry.

• Filters spurious divergent modes that may survive pressure projection on a center-sampled velocity field.

• A microsolver that defragments geometry.

• A microsolver that creates a signed distance field out of geometry.

• A micro solver that transfers meta data on simulation objects to and from geometry attributes.

• Blends a set of SOP volumes into a set of new collision fields for the creation of a guided simulation.

• A microsolver that copies Impact data onto point attributes.

• A microsolver that applies forces to a particle fluid system.

• A microsolver that solves its subsolvers at a regular interval.

• A microsolver that clamps a field within certain values.

• A microsolver that keeps particles within a box.

• A microsolver that combines multiple fields or attributes together.

• A microsolver that adaptively sharpens a field.

• A microsolver that looksup field values according to a position field.

• A microsolver that rebuilds fields to match in size and resolution to a reference field.

• A microsolver that arbitrary simulation data between multiple machines.

• A microsolver that exchanges boundary data between multiple machines.

• A microsolver that exchanges boundary data between multiple machines.

• A microsolver that balances slices data between multiple machines.

• A microsolver that exchanges boundary data between multiple machines.

• Executes the provided kernel with the given parameters.

• A microsolver that counts the number of particles in each voxel of a field.

• A microsolver that computes pairwise collision forces between particles that represent instanced spheres.

• A microsolver that moves particles to lie along a certain isosurface of an SDF.

• A microsolver that separates adjacent particles by adjusting their point positions..

• A microsolver that copies a particle system’s point attribute into a field.

• A microsolver that converts a particle system into a signed distance field.

• A microsolver that removes the divergent components of a velocity field.

• A microsolver that removes the divergent components of a velocity field using an adaptive background grid to increase performance.

• A microsolver that removes the divergent components of a velocity field using a multi-grid method.

• A microsolver that removes the divergent components of a velocity field.

• A microsolver that reduces a field to a single constant field .

• A microsolver that reduces surrounding voxels to a single value.

• A microsolver that reinitializes a signed distance field while preserving the zero isocontour.

• A microsolver that repeatedly solves its input.

• A microsolver that changes the size of fields.

• A microsolver that resizes a fluid to match simulating fluid bounds

• A microsolver that initializes a rest field.

• A microsolver that converts an SDF field to a Fog field.

• A microsolver that computes the forces to treat the fluid simulation as sand rather than fluid.

• A microsolver that seeds marker particles around the boundary of a surface.

• A microsolver that seeds particles uniformly inside a surface.

• Applies a Shredding Force to the velocity field specified.

• A microsolver that computes slice numbers into an index field.

• Adjusts a fluid velocity field to match collision velocities.

• A microsolver that calculates the forces imparted by a strain field.

• A microsolver that updates the strain field according to the current velocity field.

• A microsolver that substeps input microsolvers.

• A microsolver that snaps a surface onto a collision surface.

• A microsolver that calculates a surface tension force proportional to the curvature of the surface field.

• A microsolver that synchronizes transforms of simulation fields.

• A microsolver that applies a force towards a target object.

• Modifies the temperature of a FLIP over time.

• Applies Turbulence to the specified velocity field.

• Up-scales and/or modifies a smoke, fire, or liquid simulations.

• A microsolver that reorients geometry according to motion of a velocity field.

• A microsolver that applies viscosity to a velocity field.

• A microsolver that seeds flip particles into a new volume region.

• Remaps a field according to a ramp.

• Applies a confinement force on specific bands of sampled energy.

• Applies a vortex confinement force to a velocity field.

• Applies a confinement force on specific bands of sampled energy.

• A microsolver that applies forces to a velocity field or geometry according to vorticle geometry.

• A DOP node that adds the appropriately formatted data to represent vorticles.

• A DOP node that recycles vorticles by moving them to the opposite side of the fluid box when they leave.

• A microsolver that performs a wavelet decomposition of a field.

• A microsolver that applies a wind force.

• Runs CVEX on geometry attributes.

• Runs a VEX snippet to modify attribute values.

• Applies a gravity-like force to objects.

• Creates a ground plane suitable for RBD or cloth simulations.

• Creates simulation object groups.

• Defines a constraint relationship that must always be satisfied.

• Attaches the appropriate data for Hybrid Objects to an object.

• Stores filtered information about impacts on an RBD object.

• Applies an impulse to an object.

• Creates an index field.

• Visualizes an index field.

• Creates DOP Objects according to instance attributes

• Marks a simulation object as intangible or tangible.

• Stores the name of the scene level object source for this DOP object.

• Apply forces on objects using a force field defined by metaballs.

• Creates a matrix field.

• Visualizes a matrix field.

• Merges multiple streams of objects or data into a single stream.

• Modifies or creates options on arbitrary data.

• Defines an object’s position, orientation, linear velocity, and angular velocity.

• Unified visualization of multiple fields.

• A DOP that transfers arbitrary simulation data between multiple machines.

• Does nothing.

• Creates position information from an object’s transform.

• Serves as the end-point of the simulation network. Has controls for writing out sim files.

• Uses vortex filaments to move particles.

• A POP node that uses velocity volumes to move particles.

• A POP node that attracts particles to positions and geometry.

• A POP node that copies volume values into a particle attribute.

• A POP node that resets the stopped attribute on particles, waking them up.

• A POP node that applies a force around an axis.

• A POP node that reacts to collisions.

• A POP node that detects and reacts to collisions.

• A POP node marks particles to ignore implicit collisions.

• A POP node that colors particles.

• A POP node that creates forces generated from a curve.

• A POP node that applies drag to particles.

• A POP node that applies drag to the spin of particles.

• A POP node that applies a conical fan wind to particles.

• A POP node that creates a simple fireworks system.

• A POP node that floats particles on the surface of a liquid simulation.

• A POP node that applies a flocking algorithm to particles.

• Controls local density by applying forces between nearby particles.

• A POP node that applies forces to particles.

• A POP node that applies sand grain interaction to particles.

• A POP node that groups particles.

• A POP node that sets up the instancepath for particles.

• A POP node that applies forces between particles.

• A POP node that kills particles.

• A POP node that limits particles.

• A POP node that applies forces within the particle’s frame.

• A POP solver that generates particles at a point.

• A POP node makes a particle look at a point.

• A POP node that applies forces according to metaballs.

• Converts a regular particle system into a dynamic object capable of interacting correctly with other objects in the DOP environment.

• A POP node that sets various common attributes on particles.

• A POP node that sets attributes based on nearby particles.

• A POP Node that generates particles from incoming particles.

• A POP node that creates a spongy boundary.

• A POP solver updates particles according to their velocities and forces.

• A POP node that generates particles from geometry.

• A POP node that sets the speed limits for particles.

• A POP node that sets the spin of particles..

• A POP node that uses the vorticity of velocity volumes to spin particles.

• A POP node that sets the sprite display for particles.

• Applies force to agents/particles to align them with neighbors.

• Applies anticipatory avoidance force to agents/particles to avoid potential future collisions with other agents/particles.

• Applies forces to agents/particles to bring them closer to their neighbors.

• Applies forces to agents/particles calulated using a VOP network.

• Applies force to agents/particles to avoid potential collisions with static objects.

• Applies force to agents/particles according to directions from a path curve.

• Applies force to agents/particles to move them toward a target position.

• Apply force to agents/particles to move them apart from each other.

• Used internally in the crowd solver to integrate steering forces.

• Constrains agent velocity to only go in a direction within a certain angle range of its current heading, to prevent agents from floating backward.

• Apply forces to agents/particles to create a random motion.

• A POP node that creates a new stream of particles.

• A POP node that applies torque to particles, causing them to spin.

• Runs CVEX on a particle system.

• A POP node that directly changes the velocity of particles.

• A POP node that applies wind to particles.

• Runs a VEX snippet to modify particles.

• Emits particles into a particle fluid simulation.

• Removes fluid particles that flow inside of a specified boundary from a simulation.

• Visualizes particles.

• Creates simulation object groups based on an expression.

• Defines the base physical parameters of DOP objects.

• Applies a force to an object from a particular location in space.

• Creates position information from a point on some SOP geometry.

• Associates a position and orientation to an object.

• Sets and configures a Pyro solver. This solver can be used to create both fire and smoke.

• Performs a sparse pyro simulation on the given object. This solver can be used to create both fire and smoke.

• Constrains an RBD object to a certain orientation.

• Constrains an RBD object to have a certain orientation, but with a set amount of springiness.

• Automatically freezes RBD Objects that have come to rest

• Attaches the appropriate data for RBD Objects to an object.

• Creates a number of RBD Objects from SOP Geometry. These individual RBD Objects are created from the geometry name attributes.

• Constrains an object to two constraints, creating a rotation similar to a hinge or a trapeze bar.

• Creates an RBD Object from SOP Geometry.

• Creates a single DOP object from SOP Geometry that represents a number of RBD Objects.

• Constrains an RBD object a certain distance from the constraint.

• Creates a simulation object at each point of some source geometry, similarly to how the Copy surface node copies geometry onto points.

• Sets and configures a Rigid Body Dynamics solver.

• Constrains an object to remain a certain distance from the constraint, with a set amount of springiness.

• Alters the state information for an RBD Object.

• Saves the state of a DOP network simulation into files.

• Applies forces to an object according to the difference between two reference frames.

• Sets and configures a Rigid Body Dynamics solver.

• Attaches the appropriate data for Ripple Objects to an object.

• Creates an object from existing geometry that will be deformed with the ripple solver.

• Animates wave propagation across Ripple Objects.

• Creates a signed distance field representation of a piece of geometry that can be used for collision detection.

• A microsolver that performs general calculations on a pair consisting of a DOP field and a SOP volume/VDB.

• Creates a scalar field from a SOP Volume.

• Creates a vector field from a SOP Volume Primitive.

• Creates a scalar field.

• Visualizes a scalar field.

• Defines the internal seam angle.

• Defines the mass density of a Cloth Object.

• Divides a particle system uniformly into multiple slices along a line.

• Specifies a cutting plane to divide a particle system into two slices for distributed simulations.

• Constrains an object to rotate and translate on a single axis, and limits the rotation and translation on that axis.

• Attaches the appropriate data for Smoke Objects to an object.

• Creates an Smoke Object from SOP Geometry.

• Creates an empty smoke object for a pyro simulation.

• Sets and configures a Smoke solver. This is a slightly lower-level solver that is the basis for the Pyro solver.

• Performs a sparse smoke simulation on the given object. This is a slightly lower-level solver that is the basis for the sparse pyro solver.

• Constrains a set of points on a soft body object to a certain position using a hard constraint or soft constraint.

• Constrains a point on a soft body object to a certain position.

• Constrains a point on a soft body to a certain position, with a set amount of springiness.

• Defines how a soft body object responds to collisions.

• Defines how a Soft Body Object responds to collisions.

• Defines how a Soft Body Object responds to collisions.

• Defines how a Soft Body Object responds to collisions.

• Allows the user to import the rest state from a SOP node.

• Sets and configures a Soft Body solver.

• Defines the strengths of the soft constraint on a soft body object.

• Controls the anisotropic behavior of a Solid Object.

• Attaches the appropriate data for Solid Objects to an object.

• Defines the mass density of a Solid Object.

• Defines how a Solid Object reacts to strain and change of volume.

• This builds a tree of spheres producing bounding information for an edge cloud.

• This builds a tree of spheres producing bounding information for a point cloud.

• Splits an incoming object stream into as many as four output streams.

• Creates a Static Object from SOP Geometry.

• Allows you to inspect the behavior of a static object in the viewport.

• Control the thickness of the object that collides with cloth.

• Passes one of the input object or data streams to the output.

• Creates a Terrain Object from SOP Geometry.

• Defines a way of resolving collisions between two rigid bodies.

• Applies a uniform force and torque to objects.

• Applies forces on the objects according to a VOP network.

• Creates a vector field.

• Visualizes a vector field.

• Modifies common Vellum Constraint properties during a Vellum solve.

• Microsolver to create Vellum constraints during a simulation.

• Creates a DOP Object for use with the Vellum Solver.

• Blends the current rest values of constraints with a rest state calculated from the current simulation or external geometry.

• Sets and configures a Vellum solver.

• A Vellum node that creates Vellum patches.

• Applies an impulse to an object.

• A microsolver to create soft references to visualizers on itself.

• Imports SOP source geometry into smoke, pyro, and FLIP simulations.

• Defines a way of resolving collisions involving two rigid bodies with volume.

• Attaches the appropriate data to make an object fractureable by the Voronoi Fracture Solver

• Defines the parameters for dynamic fracturing using the Voronoi Fracture Solver

• Dynamically fractures objects based on data from the Voronoi Fracture Configure Object DOP

• Applies a vortex-like force on objects, causing them to orbit about an axis along a circular path.

• Creates a Whitewater Object that holds data for a whitewater simulation.

• Sets and configures a Whitewater Solver.

• Applies forces to resist the current motion of objects relative to a turbulent wind.

• Constrains a wire point’s orientation to a certain direction.

• Constrains a wire point’s orientation to a certain direction, with a set amount of springiness.

• Attaches the appropriate data for Wire Objects to an object.

• Defines the elasticity of a wire object.

• Constraints a wire point to a certain position and direction.

• Creates a Wire Object from SOP Geometry.

• Defines the physical parameters of a wire object.

• Defines the plasticity of a wire object.

• Sets and configures a Wire solver.

• Defines a way of resolving collisions involving a wire object and DOPs objects with volumetric representations.

• Defines a way of resolving collisions between two wires.