Houdini 18.5 Nodes Geometry nodes

Pyro Trail Path geometry node

Generates curves to use as trails for the Pyro Trail Source node.

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Since 18.5

Overview

This node is a higher level tool to quickly generate pyro trail paths. It takes the incoming points and generates a cloud of points around them using the Pyro Scatter From Burst node, followed by a Ballistic Path node to generate the paths based on the scattered points, without the need of any particle simulation. If no input is provided, it creates trails shooting out from to the origin.

Tip

If you dive inside this node, some of the attributes can be changed on the generated points before they are used to generate the paths.

Using the time attribute

Each point on the curve stores a time attribute, which always starts at 0 on the first point of each curve, and increases with each consecutive point on the curve, indicating the position of the projectile on the path at a given time.

Warning

This attribute is used by the Pyro Trail Source node, so it must be preserved.

If you need to extract the point where the projectile is at a given time, use the Extract Point From Curve node with the Distance Attribute set to time and Cut At set to Current Time.

Since time starts at 0 for each path, you must offset its value if your timeline starts at a frame other than 1.

For example, if you want to offset time manually to extract the projectile from the path starting from frame 1001, do the following.

  1. Append an Attribute Adjust Float SOP with the Attribute Name set to time.

  2. Make sure Operation is set to Add.

  3. Set the Constant Value to 1001.

  4. Set the Unit Settings to Time, which will convert the value of 1001 into units of time.

    This will offset time attribute values by 41.666 for every point on the trails.

  5. Append an Extract Point From Curve SOP with the Distance Attribute set to time and Cut At set to Current Time. This will ensure to extract a point based on the time attribute using the global time.

Tip

You can manipulate the time attribute to slow down or speed up the projectile along its trajectory. For example, multiplying time values by 2 will uniformly slow down the flight.

Using the startframe attribute

This node also creates a float type primitive attribute called startframe, which stores the frame number when the projectile is launched on the path. When startframe stores values other than 1, it must be combined with the time point attribute. Pyro Trail Source will automatically do this combination if a primitive startframe attribute is found on the curves, making sure the trail source starts at the right time.

To combine the startframe attribute with the time attribute manually and extract the projectile from the path, do the following.

  1. Append an Attribute Promote node.

  2. Set the Original Name to startframe.

  3. Set the Original Class to Primitive.

  4. Set the Promotion Method to First Match.

    This will transfer the startframe attribute from curve primitives to their points.

  5. Append an Attribute Adjust Float node with the Attribute Name set to time.

  6. Set Adjust With to Attribute.

  7. Make sure Operation is set to Add.

  8. Set the Adjustment Attribute to startframe.

  9. Set the Unit Settings to Time.

    For each point, this will convert the value of startframe from frames to seconds and add the result to time.

  10. Append an Extract Point From Curve node with its Distance Attribute set to Time and Cut At set to Current Time.

    This will ensure the extract a point based on time attribute using the global time.

Customizing Trails

It is possible to generate trails for multiple bursts with one node. By default, all bursts will have the same properties, as set by the node’s parameters (such as Initial Size, Direction, etc.). To vary these properties for each burst, select the Set Varying option on the menu next to the corresponding parameter. This will use a different random value in the provided range for each input point. These generated random numbers are seeded with point numbers by default. To use a custom integer attribute instead, set Randomization By to Seed Attribute. This will ensure that randomized properties will remain the same for an input point even if points are shuffled or removed from the input, provided value of the Seed Attribute stays the same.

You can also manually override parameter values with attributes. For example, if the input geometry has a pscale point attribute, its values can be used instead of the global Initial Size. This allows you to finely control the size of each burst. To do this, the menu next to the corresponding parameter must also be set to Use Attribute.

Parameters that can be controlled by point attributes are listed in the table below.

Parameter Name

Range

Attribute Name

Attribute Type

Initial Size

0 to ∞

pscale

float

Direction

(-1,-1,-1) to (1,1,1)

N

vector

Number of Trails

0 to ∞

copynum

integer

Spread Start Angle

0 to 180

spread_startangle

float

Spread Angle

0 to 180

spread_angle

float

Azimuth Start Angle

0 to 360

azimuth_startangle

float

Azimuth Angle

0 to 360

azimuth_angle

float

Line Start

0 to ∞

line_start

float

Line Length

0 to ∞

line_length

float

Velocity Scale

0 to ∞

vscale

float

Drag

0 to ∞

drag

float

Mass

0 to ∞

mass

float

Start Frame

∞ to ∞

startframe

float

Trail Duration

0 to ∞

life

float

Speed Scale

0 to ∞

speed

float

Collisions

This node is not able to handle colliders to the same level as a particle simulation. However, a basic clipping and a collision system has been created to handle simple use-cases. If you need more advanced collision handling, you need to run a particle simulation to obtain ballistic paths.

To make a particle simulation with the generated trail paths, do the following.

  1. Create Pyro Scatter From Burst node and change its parameters to match this node.

  2. Choose the Simulated Trails option from the Quick Setup dropdown menu on the Pyro Scatter From Burst node.

    This will generate a particle simulation setup that is converted into pyro trails.

Parameters

General

Group

The subset of the input geometry points to use for point cloud generation. Leave this blank to use all points.

Guide Display

Set this menu to Distribution Guide to visualize where trails can originate. This is determined by Spread Angle, Spread Start Angle, Azimuth Angle and Azimuth Start Angle.

Quick Setups

This menu lets you run some simple scripted setups to help with the most common tasks.

Single Input Point

Creates an Add node with a single point that is ready to be positioned where you need the explosion to happen.

Color by Start Frame

Creates an Attribute Wrangle node upstream that helps you visualize the startframe point attribute over time to see when each input point is triggered.

Pyro Trail Source

Creates a Pyro Trail Source node to generate source points from the trails. These points can be rasterized into volumes that can serve as sources for a pyro simulation.

Initialize

Force Uniform will set all parameter override menus to Set Uniform. This is useful if you want all scatter properties to be controlled by the parameter interface. Use Attribute will look for incoming attributes and corresponding parameters will be set to Use Attribute.

Additional Guides

Bursts usually disappear soon after their creation, which can makes it difficult to visualize them together with the trails. Turn this on to see pyro bursts as guides while displaying this node to help synchronize the animation of different elements. It can accept a white-space separated list of Pyro Burst Source nodes.

Fuse Input Points

When multiple input points are used for one explosion by the Pyro Burst Source SOP, you usually only need one input point to generate the trails. Enabling this allows you to fuse all incoming points into one or fuse them together by matching attribute values of a custom attribute. When points are fused together, the startframe point attribute will be set to the minimum value of all fused point values, while direction (N) will be averaged.

None

No points will be fused together, all points will contribute to generate trails.

All Into One

All incoming points will be fused to a single point that will be used for trail generation.

By Attribute

Points that have the same value for Match Attribute will be fused into a single source.

Match Attribute

The attribute to control which points will be fused together. To fuse points together, they have to have the same attribute value. This must be an integer attribute.

Randomization By

Controls how the random selection is seeded for parameters that are using Set Varying. Topology changes on the input geometry can shift element numbers, causing a different random selection to be used. Seed Attribute lets you provide an integer attribute to make sure the random value is not dependent on element order.

Click the randomization button on the right side of this parameter to randomize the value per incoming element. This will create/select a corresponding attribute adjust node to give you greater control over the parameter’s value.

Seed Attribute

The integer type attribute to use for random selection for parameters that are using Set Varying.

Source

Shape

Shape

The trails can be launched in a spherical shape around the incoming points or along the burst’s direction (as set by Direction) when this is set to Line. Use Sphere if you want trails launching from the center of the explosion or Line when you want trails shooting out from the rising mushroom cloud.

Sphere

Line

Initial Size

The starting size of the burst in which trails will be launched. A value of 1 means the diameter of the burst is roughly 1 unit.

Click the randomization button on the right side of this parameter to randomize the value per incoming element. This will create/select a corresponding attribute adjust node to give you greater control over the parameter’s value.

Size Scale

Scales the existing pscale attribute by this amount when the menu is set to Scale Attribute. This allows you to quickly scale your burst without adjusting the attribute values.

Variation

Sets the maximum allowed variation. Sizes will be between Initial Size - Variation and Initial Size + Variation.

Seed

Controls the random selection for variation. Change this value if the current variation is undesirable.

Direction

The direction of the burst. You can change the direction to make the trails come out from the side of a building, for example.

When Shape is set to Sphere, this vector also corresponds to spread angle of 0. When using Line (Shape), the Direction controls the line that shoots out trails.

Click the randomization button on the right side of this parameter to randomize the value per incoming element. This will create/select a corresponding attribute adjust node to give you greater control over the parameter’s value.

Variation

Sets the maximum allowed variation in degrees. The varied direction will spread out in a cone shape from Direction.

Seed

Controls the random selection for variation. Change this value if the current variation is undesirable.

Shape Offset

Controls the random scattering of starting points for trails. Change this value to obtain different trails for the same set of shape parameters.

Trail Distribution

Number of Trails

The number of trails to generate per input point. Increase this parameter to create more trails.

Click the randomization button on the right side of this parameter to randomize the value per incoming element. This will create/select a corresponding attribute adjust node to give you greater control over the parameter’s value.

Variation

Sets the maximum allowed variation. Trail counts per input point will be between Number of Trails - Variation and Number of Trails + Variation.

Seed

Controls the random selection for variation. Change this value if the current variation is undesirable.

Spread Start Angle

When Shape is set to Sphere, it sets the minimum angle the scattered points can spread out from the burst’s direction vector (as set by Direction). Set Guide Display to Distribution Guide to help visualize the given angle.

Click the randomization button on the right side of this parameter to randomize the value per incoming element. This will create/select a corresponding attribute adjust node to give you greater control over the parameter’s value.

Variation

Sets the maximum allowed variation in degrees. Start angles will be between Spread Start Angle - Variation and Spread Start Angle + Variation.

Seed

Controls the random selection for variation. Change this value if the current variation is undesirable.

Spread Angle

When Shape is set to Sphere, it sets the angle trails can spread from Spread Start Angle towards the opposite of burst direction (as set by Direction). Set this to 180 degrees on a node with default settings to make the trails shoot out in all directions. Set Guide Display to Distribution Guide to help visualize the given angle.

Click the randomization button on the right side of this parameter to randomize the value per incoming element. This will create/select a corresponding attribute adjust node to give you greater control over the parameter’s value.

Variation

Sets the maximum allowed variation in degrees. Spread angles will fall between Spread Angle - Variation and Spread Angle + Variation.

Seed

Controls the random selection for variation. Change this value if the current variation is undesirable.

Line Start

When Shape is set to Line, the trails are generated around a line representing the burst direction (as set by Direction). This parameter sets how far away this line should be created from its input point in world units.

Click the randomization button on the right side of this parameter to randomize the value per incoming element. This will create/select a corresponding attribute adjust node to give you greater control over the parameter’s value.

Variation

Sets the maximum allowed variation for Line Start. The generated values will be between Line Start - Variation to Line Start + Variation.

Seed

Controls the random selection for variation. Change this value if the current variation is undesirable.

Line Length

When Shape is set to Line, the trails are generated around a line representing the burst direction (as set by Direction). This parameter sets the length of the line in world units.

Click the randomization button on the right side of this parameter to randomize the value per incoming element. This will create/select a corresponding attribute adjust node to give you greater control over the parameter’s value.

Variation

Sets the maximum allowed variation for Line Length. The generated values will be between Line Length - Variation to Line Length + Variation.

Seed

Controls the random selection for variation. Change this value if the current variation is undesirable.

Azimuth Start Angle

Azimuth controls how trails are generated around the burst direction (as set by Direction), therefore you can use it to generate trails only on a desired side of the explosion. By default, the value of 0 will create trails on the +X axis and they are rotated around the burst direction vector counter-clockwise as the value increases.

Click the randomization button on the right side of this parameter to randomize the value per incoming element. This will create/select a corresponding attribute adjust node to give you greater control over the parameter’s value.

Variation

Sets the maximum allowed variation in degrees. The variation will be from Value - Variation to Value + Variation.

Seed

Controls the random selection for variation. Change this value if the current variation is undesirable.

Azimuth Angle

Azimuth controls how trails are generated around the burst direction (as set by Direction), therefore you can use it to generate trails only on a desired side of the explosion. Increasing this value will spread out the trails from the Azimuth Start Angle around the burst direction both clockwise and counter-clockwise. The value of 360 means that trails will be created all around the burst direction.

Click the randomization button on the right side of this parameter to randomize the value per incoming element. This will create/select a corresponding attribute adjust node to give you greater control over the parameter’s value.

Variation

Sets the maximum allowed variation in degrees. The generated values will be between Azimuth Angle - Variation and Azimuth Angle + Variation.

Seed

Controls the random selection for variation. Change this value if the current variation is undesirable.

Prune by Noise

Removes some of the trails based on a noise pattern. Use this to create more interesting trail patterns. When this checkbox is turned on, Number of Trails might need to be increased to compensate for the removed trails.

Size

Controls base feature size of the generated noise. The value applies to each axis.

Offset

The offset along the Y-axis. Change this value if the current noise pattern is undesirable.

Roughness

The scale increment between iterations of fractal noise. The higher the value, the larger the "jaggedness" added to the output.

Radius Along Length

When Shape is set to Line, this controls the radius in which the points can be scattered along the length of the line. When the ramp’s value is 1, the radius is equal to Initial Size.

Trail Generation

Velocity

Velocity Scale

Sets the length (magnitude) of the launch velocity for the trails. Increase this to make the trails shoot out faster and cover larger distances during their life time.

Click the randomization button on the right side of this parameter to randomize the value per incoming element. This will create/select a corresponding attribute adjust node to give you greater control over the parameter’s value.

Variation

Sets the maximum allowed variation for velocity scale. The generated values will fall between Velocity Scale - Variation and Velocity Scale + Variation.

Seed

Controls the random selection for variation. Change this value if the current variation is undesirable.

Top Spread Angle

Controls "verticality" of the paths for points further away from the center, when Shape is set to Line. The spread angle refers to the angle between the burst’s direction (as set by Direction) and a path’s starting velocity vector. Therefore, a spread angle of 0 will result in a path that’s aimed in the burst’s direction, and a spread angle of 90 will result in a path that starts out perpendicular to the burst’s direction. In the common case of Direction pointing away from Gravity, values near 90 will produce paths that are shooting out horizontally at the top of the emission line. Use the +/- button to quickly randomize the value per trail. The spread angle for the starting point of a path is fully determined by its distance to the burst center along the direction. When this distance is at Line Start or its sum with Line Length, spread angle will be set to Bottom Spread Angle and Top Spread Angle, respectively. The spread angle is linearly interpolated for distances between them.

Variation

Sets the maximum allowed variation in degrees. The generated values will be between Top Spread Angle - Variation and Top Spread Angle + Variation.

Seed

Controls the random selection for variation. Change this value if the current variation is undesirable.

Bottom Spread Angle

Controls "verticality" of the paths for points closer to the center, when Shape is set to Line. The spread angle refers to the angle between the burst’s direction (as set by Direction) and a path’s starting velocity vector. Therefore, a spread angle of 0 will result in a path that’s aimed in the burst’s direction, and a spread angle of 90 will result in a path that starts out perpendicular to the burst’s direction. In the common case of Direction pointing away from Gravity, values near 90 will produce paths that are shooting out horizontally at the bottom of the emission line. Use the +/- button to quickly randomize the value per trail. The spread angle for the starting point of a path is fully determined by its distance to the burst center along the direction. When this distance is at Line Start or its sum with Line Length, spread angle will be set to Bottom Spread Angle and Top Spread Angle, respectively. The spread angle is linearly interpolated for distances between them.

Variation

Sets the maximum allowed variation in degrees. The generated values will be between Bottom Spread Angle - Variation and Bottom Spread Angle + Variation.

Seed

Controls the random selection for variation. Change this value if the current variation is undesirable.

Enable Direction Noise

When this checkbox is turned on, it changes the direction of the trails based on a noise pattern. Use this to randomize and create more variation in the trail directions.

Amplitude

Sets the strength of the noise. Higher values will create more variation between the trails.

Size

Controls base feature size of the generated noise. The value applies to each axis.

Offset

The offset along the Y-axis. Change this value if the current noise pattern is undesirable.

Roughness

The scale increment between iterations of fractal noise. The higher the value, the larger the "jaggedness" added to the output.

Enable Length Noise

When this checkbox is turned on, it changes the length (magnitude) of the launch velocity for the trails based on a noise pattern. Increasing launch velocity makes the trails shoot out faster and cover more distance during their lifetime.

Scale Min

Sets how much of the launch velocity can be scaled down from its original length. The value of 1 means, that no velocities will be shorter than their original length.

Scale Max

Sets how much of the launch velocity can be scaled up from it’s original length. The value of 1 means, that no velocities will be longer than their original length.

Size

Controls base feature size of the generated noise. The value applies to each axis.

Offset

The offset along the Y-axis. Change this value if the current noise pattern is undesirable.

Roughness

The scale increment between iterations of fractal noise. The higher the value, the larger the "jaggedness" added to the output.

Limit Length

Limits the magnitude of the launch velocity. Use it to limit the minimum or the maximum launch speeds.

Limit Min

Limits the minimum launch speed.

Limit Max

Limits the maximum launch speed.

Ballistic Properties

Drag

Sets the air resistance for the projectiles. Higher values will result in faster loss of energy and shorter travel distance. A Drag of zero will produce a symmetric arc.

Pyro Trail Paths with Drag values from left to right : 3, 2, 1, 0.5, 0.

Click the randomization button on the right side of this parameter to randomize the value per incoming element. This will create/select a corresponding attribute adjust node to give you greater control over the parameter’s value.

Variation

Sets the maximum allowed variation. Drag values will fall between Drag - Variation and Drag + Variation.

Seed

Controls the random selection for variation. Change this value if the current variation is undesirable.

Mass

Sets the mass for the projectile. Higher values will cause the projectile to more strongly resist drag and travel a longer distance.

Pyro Trail Paths with Mass values from left to right : 0, 0.5, 1, 2, 3.
Combined view of Drag (yellow) and Mass (green) values.

Click the randomization button on the right side of this parameter to randomize the value per incoming element. This will create/select a corresponding attribute adjust node to give you greater control over the parameter’s value.

Variation

Sets the maximum allowed variation. Projectile masses will be between Mass - Variation and Mass + Variation.

Seed

Controls the random selection for variation. Change this value if the current variation is undesirable.

Gravity

Sets the force that attracts the projectile towards the ground. Set all components to zero if you want straight trails, which are not affected by gravity.

FPS

The number of divisions in the path for every second of time. Usually one wants a division per frame, thus this is often related to your frames per second.

Substeps

Sets how many times to divide the trail into further segments. The larger the number, the more points will be created for each curve to help with post-deformations. You do not need to change this parameter from the default, if you do not intend to apply any post-deformation.

Start Frame

Start Frame

This node sets the startframe primitive attribute on the generated curves to indicate when each trail is to start. This parameter can be used to control timing of the projectiles. The startframe attribute gets set on the incoming points before the trails are seeded; therefore, all points created from the same input point will have the same start frame. Use Offset per Point to vary the start frame per scattered point. Use the button to the right of this parameter to visualize start frames for scattered points; grey points haven’t triggered at the current frame, while red ones have.

Note

As the float type time point attribute is used to tell where the projectile is on the path at a given time, the startframe attribute is combined with time when using Pyro Trail Source following this node. Therefore you must make sure to preserve this attribute. For more information, see Using the time attribute and Using the startframe attribute.

Click the randomization button on the right side of this parameter to randomize the value per incoming element. This will create/select a corresponding attribute adjust node to give you greater control over the parameter’s value.

Start Frame Visualizer

When this is turned on, it colors trails that have not started as grey, and already started trails as red.

Offset

Offsets the existing startframe attribute by this amount when the menu is set to Shift Forward or Shift Backward. This allows you to quickly change the startframe attribute without needing to adjust the attribute value. This value sets startframe on the incoming points before the trails are generated, so all paths created from the same input point will have the same start frame.

Variation

Sets the maximum allowed variation. The generated values will cover the range from Start Frame to Start Frame + Variation.

Seed

Controls the random selection for variation. Change this value if the current variation is undesirable.

Offset per Point

Sets the maximum allowed start frame offset for each trail. You need to turn this on to vary the start frames for trails generated from the same input point. This will set the offset value as unit of frames, when you only need couple of frames as offset. However, if you need an offset longer than a few seconds, using As Time Duration might be a better alternative. Random Distribution will pick startframe values between Start Frame and Start Frame + Offset per Point, which can be useful when Shape is set to Sphere. Use Along Direction when Shape is set to Line to start the trails gradually along the burst’s direction (as set by Direction).

Offset per Point

Sets the maximum allowed start frame offset extension for each trail as unit of time. It might be easier to provide the offset as unit of time when the trails need to live longer than a few seconds.

Seed

Controls the random selection for variation. Change this value if the current variation is undesirable.

Start Frame Over Length

When Shape is set to Line, this ramp allows you to start the trails that are closer to the burst center before ones that are further away. The left side of the ramp applies to trails that are the closest to the burst center, while the right side is for trails that are the furthest. When the ramp’s value is set to 0, it will set startframe to the value given by Start Frame. When the ramp’s value is 1, it will set startframe to Start Frame + Offset per Point.

Timing

Trail Duration

Sets the length of the trails in frames. Higher values produce longer trails.

Click the randomization button on the right side of this parameter to randomize the value per incoming element. This will create/select a corresponding attribute adjust node to give you greater control over the parameter’s value.

Trail Duration

Sets the length of the trails in seconds. Higher values produce longer trails.

Variation

Sets the maximum allowed variation for Trail Duration. The generated values will be between Trail Duration and Trail Duration + Variation.

Seed

Controls the random selection for variation. Change this value if the current variation is undesirable.

Speed Scale

Sets how fast the projectile is moving on the trail path. Lowering this value will make the projectiles move slower, while increasing this value will make them move faster.

Click the randomization button on the right side of this parameter to randomize the value per incoming element. This will create/select a corresponding attribute adjust node to give you greater control over the parameter’s value.

Variation

Sets the maximum allowed variation for Speed Scale. The generated scales will be between Speed Scale and Speed Scale + Variation.

Seed

Controls the random selection for variation. Change this value if the current variation is undesirable.

Basic Collision

Clip Below Height

Turning on this checkbox lets you clip projectiles that fall below Clip Height on the Y-axis.

Clip Height

The height to use for clipping. Trajectories will terminate once the Y coordinate falls below this value.

Enable Static Collision

Turns on a basic collision detection system for the path to collide with objects.

Collision Geometry Path

The SOP path to the geometry the projectile paths need to collide with. If the geometry contains a kill primitive attribute that is set to 1, trajectories will terminate when they hit that primitive; otherwise, they will bounce and continue.

Number of Bounces

The maximum number of allowed bounces for projectile paths. After this number of bounces, the path will terminate. Set this to 0, if you want to eliminate all projectiles on the first collision hit.

Bounce

Specifies what fraction of the original speed is maintained on collision in the direction of the collision normal. A value of 1 will simply reverse this normal component of velocity, whereas smaller values will also reduce it. A value of 0 will kill the projectile upon collision.

Bounce Forward

Specifies what fraction of the original speed is maintained in the tangential plane of the collision. A value of 1 will leave the tangential velocity unaffected; a value of 0 will eliminate the tangential component of velocity after the collision.

Output Attributes

Generic Attributes

Copy Input Attributes

Copies custom created point attributes from the input points to the generated trails. This will ignore copying all internally used attributes.

Attributes

Only copy attributes whose names match this pattern. The default * copies all attributes. This will ignore copying all internally used attributes.

Promote Input Attributes

When this checkbox is turned on, attributes will be promoted from input points to curve primitives that they generate.

Trail Id

The primitive attribute storing a unique id attribute for each generated path.

Trail Index

The primitive attribute storing the index number of the generated trails.

Launch Speed

The primitive attribute storing length of the velocity vector at the start of each trail.

End Time

The primitive attribute storing the time when the trail ends.

Randomization Attribute

When this checkbox is turned on, the trailid primitive attribute will be created to store the value used by the Randomization By parameter.

See also

Geometry nodes

  • Adapt to Terrain

    Adapts a character’s skeleton to conform to terrain.

  • Adaptive Prune

    Removes elements while trying to maintain the overall appearance.

  • Add

    Creates Points or Polygons, or adds points/polys to an input.

  • Agent

    Creates agent primitives.

  • Agent Animation Unpack

    Extracts animation or MotionClips from an agent primitive.

  • Agent Character Unpack

    Extracts the rest geometry, skeleton, and animation from an agent primitive.

  • Agent Clip

    Adds new clips to agent primitives.

  • Agent Clip Properties

    Defines how agents' animation clips should be played back.

  • Agent Clip Transition Graph

    Creates geometry describing possible transitions between animation clips.

  • Agent Collision Layer

    Creates a new agent layer that is suitable for collision detection.

  • Agent Configure Joints

    Creates point attributes that specify the rotation limits of an agent’s joints.

  • Agent Constraint Network

    Builds a constraint network to hold an agent’s limbs together.

  • Agent Definition Cache

    Writes agent definition files to disk.

  • Agent Edit

    Edits properties of agent primitives.

  • Agent Layer

    Adds a new layer to agent primitives.

  • Agent Look At

    Adjusts the head of an agent to look at a specific object or position.

  • Agent Pose from Rig

    Updates an agent primitive’s pose from a geometry skeleton.

  • Agent Prep

    Adds various common point attributes to agents for use by other crowd nodes.

  • Agent Proxy

    Provides simple proxy geometry for an agent.

  • Agent Relationship

    Creates parent-child relationships between agents.

  • Agent Terrain Adaptation

    Adapts agents' legs to conform to terrain and prevent the feet from sliding.

  • Agent Transform Group

    Adds new transform groups to agent primitives.

  • Agent Unpack

    Extracts geometry from agent primitives.

  • Agent Vellum Unpack

    Extracts geometry from agent primitives for a Vellum simulation.

  • Agent from Rig

    Creates an agent primitive from a geometry skeleton.

  • Alembic

    Loads the geometry from an Alembic scene archive (.abc) file into a geometry network.

  • Alembic Group

    Creates a geometry group for Alembic primitives.

  • Alembic Primitive

    Modifies intrinsic properties of Alembic primitives.

  • Alembic ROP output driver

  • Align

    Aligns a group of primitives to each other or to an auxiliary input.

  • Assemble

    Cleans up a series of break operations and creates the resulting pieces.

  • Attach Control Geometry

    Creates control geometry for SOP-based KineFX rigs.

  • Attribute Adjust Float

    Modifies floating point attribute values on the incoming geometry.

  • Attribute Adjust Integer

    Modifies integer attribute values on the incoming geometry.

  • Attribute Adjust Vector

    Modifies values for a vector-type attribute on the incoming geometry.

  • Attribute Blur

    Blurs out (or "relaxes") points in a mesh or a point cloud.

  • Attribute Cast

    Changes the size/precision Houdini uses to store an attribute.

  • Attribute Composite

    Composites vertex, point, primitive, and/or detail attributes between two or more selections.

  • Attribute Copy

    Copies attributes between groups of vertices, points, or primitives.

  • Attribute Create

    Adds or edits user defined attributes.

  • Attribute Delete

    Deletes point and primitive attributes.

  • Attribute Expression

    Allows simple VEX expressions to modify attributes.

  • Attribute Fade

    Fades a point attribute in and out over time.

  • Attribute From Pieces

    Assigns an attribute to points specifying which of a set of models should be copied/instanced to that point, randomly or based on various rules.

  • Attribute Interpolate

    Interpolates attributes within primitives or based on explicit weights.

  • Attribute Mirror

    Copies and flips attributes from one side of a plane to another.

  • Attribute Noise

    Adds or generates noise in geometry attributes.

  • Attribute Paint

    Interactively paint point attributes, such as color or deformation mask values, directly on geometry.

  • Attribute Promote

    Promotes or demotes attributes from one geometry level to another.

  • Attribute Randomize

    Generates random attribute values of various distributions.

  • Attribute Remap

    Fits an attribute’s values to a new range.

  • Attribute Rename

    Renames or deletes point and primitive attributes.

  • Attribute Reorient

    Modifies point attributes based on differences between two models.

  • Attribute String Edit

    Edits string attribute values.

  • Attribute Swap

    Copies, moves, or swaps the contents of attributes.

  • Attribute Transfer

    Transfers vertex, point, primitive, and/or detail attributes between two models.

  • Attribute Transfer By UV

    Transfers attributes between two geometries based on UV proximity.

  • Attribute VOP

    Runs a VOP network to modify geometry attributes.

  • Attribute Wrangle

    Runs a VEX snippet to modify attribute values.

  • Attribute from Map

    Samples texture map information to a point attribute.

  • Attribute from Parameters

    Creates a dictionary attribute filled with parameter values.

  • Attribute from Volume

    Copies information from a volume onto the point attributes of another piece of geometry, with optional remapping.

  • Bake ODE

    Converts primitives for ODE and Bullet solvers.

  • Bake Volume

    Computes lighting values within volume primitives

  • Ballistic Path

    Generates ballistic projectile paths from the incoming points.

  • Basis

    Provides operations for moving knots within the parametric space of a NURBS curve or surface.

  • Bend

    Applies captures such as bend, twist, taper, and squash/stretch.

  • Blast

    Deletes primitives, points, edges or breakpoints.

  • Blend Shapes

    Computes a 3D metamorphosis between shapes with the same topology.

  • Block Begin

    The start of a looping block.

  • Block Begin Compile

    The start of a compile block.

  • Block End

    The end/output of a looping block.

  • Block End Compile

    The end/output of a compile block.

  • Bone Capture

    Supports Bone Deform by assigning capture weights to bones.

  • Bone Capture Biharmonic

    Supports Bone Deform by assigning capture weights to points based on biharmonic functions on tetrahedral meshes.

  • Bone Capture Lines

    Utility node that supports Bone Capture Biharmonic by creating lines from bones with suitable attributes.

  • Bone Capture Proximity

    Supports Bone Deform by assigning capture weights to points based on distance to bones.

  • Bone Deform

    Uses capture attributes created from bones to deform geometry according to their movement.

  • Bone Link

    Creates default geometry for Bone objects.

  • Boolean

    Combines two polygonal objects with boolean operators, or finds the intersection lines between two polygonal objects.

  • Boolean Fracture

    Fractures the input geometry using cutting surfaces.

  • Bound

    Creates a bounding box, sphere, or rectangle for the input geometry.

  • Box

    Creates a cube or six-sided rectangular box.

  • Bulge

    Deforms the points in the first input using one or more magnets from the second input.

  • COP2 Network

    Imports 2d geometry from a Composite network.

  • Cache

    Records and caches its input geometry for faster playback.

  • Cap

    Closes open areas with flat or rounded coverings.

  • Capture Attribute Pack

    Converts array attributes into a single index-pair capture attribute.

  • Capture Attribute Unpack

    Converts a single index-pair capture attribute into per-point and detail array attributes.

  • Capture Correct

    Adjusts capture regions and capture weights.

  • Capture Layer Paint

    Lets you paint capture attributes directly onto geometry.

  • Capture Mirror

    Copies capture attributes from one half of a symmetric model to the other.

  • Capture Override

    Overrides the capture weights on individual points.

  • Capture Packed Geometry

    Rigidly capture input packed geometry to a SOP skeleton.

  • Capture Region

    Supports Capture and Deform operation by creating a volume within which points are captured to a bone.

  • Carve

    Slices, cuts or extracts points or cross-sections from a primitive.

  • Chain

    Repeats one or more pieces of geometry along a curve.

  • Channel

    Reads sample data from a chop and converts it into point positions and point attributes.

  • Character Blend Shapes

    Applies blend shapes to a KineFX character’s geometry using the weight attributes on its skeleton.

  • Character I/O

    Packs Character mesh, capture pose and animation, saves them to disk, and loads them back again.

  • Character Pack

    Creates a packed geometry primitive from a rest geometry, skeleton, and animation inputs.

  • Character Unpack

    Extracts the rest geometry, skeleton, and animation from an packed geometry primitive.

  • Circle

    Creates open or closed arcs, circles and ellipses.

  • Circle from Edges

    Transforms selected geometry into a circle.

  • Clay

    Lets you deform NURBS faces and NURBS surfaces by pulling points that lie directly on them.

  • Clean

    Helps clean up dirty models.

  • Clip

    Removes or groups geometry on one side of a plane, or creases geometry along a plane.

  • Cloth Capture

    Captures low-res simulated cloth.

  • Cloth Deform

    Deforms geometry captured by the Cloth Capture SOP.

  • Cloud

    Creates a volume representation of source geometry.

  • Cloud Light

    Fills a volume with a diffuse light.

  • Cloud Noise

    Applies a cloud like noise to a Fog volume.

  • Cluster

    Low-level machinery to cluster points based on their positions (or any vector attribute).

  • Cluster Points

    Higher-level node to cluster points based on their positions (or any vector attribute).

  • Collision Source

    Creates geometry and VDB volumes for use with DOPs collisions.

  • Color

    Adds color attributes to geometry.

  • Comb

    Adjust surface point normals by painting.

  • Compute Rig Pose

    Evaluates a multiparm of transform parameters and applies them to the input skeleton.

  • Compute Transform

    Recomputes world space or local space transforms for points in a hierarchy.

  • Configure Clip Info

    Edits properties of a skeleton animation or motion clip.

  • Connect Adjacent Pieces

    Creates lines between nearby pieces.

  • Connectivity

    Creates an attribute with a unique value for each set of connected primitives or points.

  • Control

    Creates simple geometry for use as control shapes.

  • Convert

    Converts geometry from one geometry type to another.

  • Convert HeightField

    Converts a 2D height field to a 3D VDB volume, polygon surface, or polygon soup surface.

  • Convert Line

    Converts the input geometry into line segments.

  • Convert Meta

    Polygonizes metaball geometry.

  • Convert Tets

    Generates the oriented surface of a tetrahedron mesh.

  • Convert VDB

    Converts sparse volumes.

  • Convert VDB Points

    Converts a Point Cloud into a VDB Points Primitive, or vice versa.

  • Convert Volume

    Converts the iso-surface of a volume into a polygonal surface.

  • Convex Decomposition

    Decomposes the input geometry into approximate convex segments.

  • Copy Stamp

    Creates multiple copies of the input geometry, or copies the geometry onto the points of the second input.

  • Copy and Transform

    Copies geometry and applies transformations to the copies.

  • Copy to Curves

    Copies geometry in the first input onto curves of the second input.

  • Copy to Points

    Copies geometry in the first input onto the points of the second input.

  • Crease

    Manually adds or removes a creaseweight attribute to/from polygon edges, for use with the Subdivide SOP.

  • Creep

    Deforms and animates a piece of geometry across a surface.

  • Cross Section Surface

    Creates a surface around cross sections.

  • Crowd Source

    Populates a crowd of agent primitives.

  • Curve

    Creates polygonal, NURBS, or Bezier curves.

  • Curveclay

    Deforms a spline surface by reshaping a curve on the surface.

  • Curvesect

    Finds the intersections (or points of minimum distance) between two or more curves or faces.

  • DOP I/O

    Imports fields from DOP simulations, saves them to disk, and loads them back again.

  • DOP Import Fields

    Imports scalar and vector fields from a DOP simulation.

  • DOP Import Records

    Imports option and record data from DOP simulations into points with point attributes.

  • DOP Network

  • Debris Source

    Generates point emission sources for debris from separating fractured rigid body objects.

  • Deformation Wrangle

    Runs a VEX snippet to deform geometry.

  • Delete

    Deletes input geometry by group, entity number, bounding volume, primitive/point/edge normals, and/or degeneracy.

  • Delete Joints

    Delete Joints on a SOP Rig.

  • DeltaMush

    Smooths out (or "relaxes") point deformations.

  • Denoise AI

    Uses machine-learning algorithms to denoise images with high quality and speed.

  • Detangle

    Attempts to prevent collisions when deforming geometry.

  • Dissolve

    Deletes edges from the input polygonal geometry merging polygons with shared edges.

  • Distance Along Geometry

    Measures the distance of the shortest path along the geometry’s edges or surfaces from each start point.

  • Distance from Geometry

    Measures distance between each point and a reference geometry.

  • Distance from Target

    Measures distance of each point from a target.

  • Divide

    Divides, smooths, and triangulates polygons.

  • Dop Import

    Imports and transforms geometry based on information extracted from a DOP simulation.

  • Draw Curve

    Creates a curve based on user input in the viewport.

  • Draw Guides

  • Dynamic Warp

    Dynamically Time-warps the first input (the Source) using the second input (the Reference) as a reference.

  • Each

    Culls the input geometry according to the specifications of the For Each SOP.

  • Edge Collapse

    Collapses edges and faces to their centerpoints.

  • Edge Cusp

    Sharpens edges by uniquing their points and recomputing point normals.

  • Edge Divide

    Inserts points on the edges of polygons and optionally connects them.

  • Edge Equalize

    Transforms selected edges so that all edges are of equal length.

  • Edge Flip

    Flips the direction of polygon edges.

  • Edge Fracture

    Cuts geometry along edges using guiding curves.

  • Edge Straighten

    Straightens selected edges.

  • Edge Transport

    Copies and optionally modifies attribute values along edges networks and curves.

  • Edit

    Edits points, edges, or faces interactively.

  • Ends

    Closes, opens, or clamps end points.

  • Enumerate

    Sets an attribute on selected points or primitives to sequential numbers or strings.

  • Error

    Generates a message, warning, or error, which can show up on a parent asset.

  • Exploded View

    Pushes geometry out from the center to create an exploded view.

  • Export Object Transforms

    Export transform attributes to object nodes.

  • Extract Centroid

    Computes the centroid of each piece of the geometry.

  • Extract Locomotion

    Extracts translation and orientation from a character using a given input joint.

  • Extract Point from Curve

    Creates new points where an interpolated attribute has a certain value on a curve.

  • Extract Transform

    Computes the best-fit transform between two pieces of geometry.

  • Extrude

    Extrudes geometry along a normal.

  • Extrude Volume

    Extrudes surface geometry into a volume.

  • FBIK Configure Joints

    Configures joint properties used by full-body inverse kinematics solvers.

  • FBIK Configure Targets

    Configures joint properties used by full-body inverse kinematics solvers.

  • FBX Animation Import

    Import animation from an FBX file as a geometry-based skeleton.

  • FBX Character Import

    Import a skinned character from an FBX file with animation.

  • FBX Skin Import

    Import skin geometry from an FBX file.

  • FEM Validate

    Visualizes the quality of a tetrahedral mesh.

  • FEM Visualize

  • FK Transfer

    Transfer forward kinematic motion to a SOP-based skeleton

  • FLIP Source

    Creates a surface or density VDB for sourcing FLIP simulations.

  • Facet

    Controls the smoothness of faceting of a surface.

  • Filament Advect

    Evolves polygonal curves as vortex filaments.

  • File

    Reads, writes, or caches geometry on disk.

  • File Cache

    Writes and reads geometry sequences to disk.

  • File Merge

    Reads and collates data from disk.

  • Fillet

    Creates smooth bridging geometry between two curves or surfaces.

  • Filmbox FBX ROP output driver

  • Find Shortest Path

    Finds the shortest paths from start points to end points, following the edges of a surface.

  • Fit

    Fits a spline curve to points, or a spline surface to a mesh of points.

  • Fluid Compress

    Compresses the output of fluid simulations to decrease size on disk

  • Font

    Creates 3D text from Type 1, TrueType and OpenType fonts.

  • Force

    Uses a metaball to attract or repel points or springs.

  • Fractal

    Creates jagged mountain-like divisions of the input geometry.

  • Full Body IK

    Transfer a motion to a SOP-based skeleton using full-body inverse kinematics algorithm.

  • Fur

    Creates a set of hair-like curves across a surface.

  • Fuse

    Merges points.

  • Geometry nodes

    Geometry nodes live inside Geo objects and generate geometry.

  • Glue Cluster

    Adds strength to a glue constraint network according to cluster values.

  • Grain Source

    Generates particles to be used as sources in a particle-based grain simulation.

  • Graph Color

    Assigns a unique integer attribute to non-touching components.

  • Grid

    Creates planar geometry.

  • Groom Blend

    Blends the guides and skin of two grooms.

  • Groom Fetch

    Fetches groom data from grooming objects.

  • Groom Pack

    Packs the components of a groom into a set of named Packed Primitives for the purpose of writing it to disk.

  • Groom Switch

    Switches between all components of two groom streams.

  • Groom Unpack

    Unpacks the components of a groom from a packed groom.

  • Group

    Generates groups of points, primitives, edges, or vertices according to various criteria.

  • Group Combine

    Combines point groups, primitive groups, or edge groups according to boolean operations.

  • Group Copy

    Copies groups between two pieces of geometry, based on point/primitive numbers.

  • Group Delete

    Deletes groups of points, primitives, edges, or vertices according to patterns.

  • Group Expand

    Expands or shrinks groups of Edges, Points, Primitives, or Vertices.

  • Group Expression

    Runs VEX expressions to modify group membership.

  • Group Find Path

    Constructs groups for paths between elements.

  • Group Joints

    Group Joints on a SOP Rig.

  • Group Paint

    Sets group membership interactively by painting.

  • Group Promote

    Converts point, primitive, edge, or vertex groups into point, primitive, edge, or vertex groups.

  • Group Range

    Groups points and primitives by ranges.

  • Group Rename

    Renames groups according to patterns.

  • Group Transfer

    Transfers groups between two pieces of geometry, based on proximity.

  • Group by Lasso

    Groups points and primitives by lasso.

  • Group from Attribute Boundary

    Creates a group that includes the boundaries of the specified attribute.

  • Guide Advect

    Advects guide points through a velocity volume.

  • Guide Collide With VDB

    Resolves collisions of guide curves with VDB signed distance fields.

  • Guide Deform

    Deforms geometry with an animated skin and optionally guide curves.

  • Guide Groom

    Allows intuitive manipulation of guide curves in the viewport.

  • Guide Group

    Creates standard primitive groups used by grooming tools.

  • Guide Initialize

    Quickly give hair guides some initial direction.

  • Guide Mask

    Creates masking attributes for other grooming operations.

  • Guide Partition

    Creates and prepares parting lines for use with hair generation.

  • Guide Skin Attribute Lookup

    Looks up skin geometry attributes under the root point of guide curves.

  • Guide Tangent Space

    Constructs a coherent tangent space along a curve.

  • Guide Transfer

    Transfer hair guides between geometries.

  • Hair Card Generate

    Converts dense hair curves to a polygon card, keeping the style and shape of the groom.

  • Hair Clump

    Clumps guide curves together.

  • Hair Generate

    Generates hair on a surface or from points.

  • Hair Growth Field

    Generates a velocity field based on stroke primitives.

  • HeightField

    Generates an initial heightfield volume for use with terrain tools.

  • HeightField Blur

    Blurs a terrain height field or mask.

  • HeightField Clip

    Limits height values to a certain minimum and/or maximum.

  • HeightField Copy Layer

    Creates a copy of a height field or mask.

  • HeightField Crop

    Extracts a square of a certain width/length from a larger height volume, or resizes/moves the boundaries of the height field.

  • HeightField Cutout by Object

    Creates a cutout on a terrain based on geometry.

  • HeightField Distort by Layer

    Displaces a height field by another field.

  • HeightField Distort by Noise

    Advects the input volume through a noise pattern to break up hard edges and add variety.

  • HeightField Draw Mask

    Lets you draw shapes to create a mask for height field tools.

  • HeightField Erode

    Calculates thermal and hydraulic erosion over time (frames) to create more realistic terrain.

  • HeightField Erode Hydro

    Simulates the erosion from one heightfield sliding over another for a short time.

  • HeightField Erode Precipitation

    Distributes water along a heightfield. Offers controls for adjusting the intensity, variability, and location of rainfall.

  • HeightField Erode Thermal

    Calculates the effect of thermal erosion on terrain for a short time.

  • HeightField File

    Imports a 2D image map from a file or compositing node into a height field or mask.

  • HeightField Flow Field

    Generates flow and flow direction layers according to the input height layer.

  • HeightField Isolate Layer

    Copies another layer over the mask layer, and optionally flattens the height field.

  • HeightField Layer

    Composites together two height fields.

  • HeightField Layer Clear

    Sets all values in a heightfield layer to a fixed value.

  • HeightField Layer Property

    Sets the border voxel policy on a height field volume.

  • HeightField Mask by Feature

    Creates a mask based on different features of the height layer.

  • HeightField Mask by Object

    Creates a mask based some other geometry.

  • HeightField Mask by Occlusion

    Creates a mask where the input terrain is hollow/depressed, for example riverbeds and valleys.

  • HeightField Noise

    Adds vertical noise to a height field, creating peaks and valleys.

  • HeightField Output

    Exports height and/or mask layers to disk as an image.

  • HeightField Paint

    Lets you paint values into a height or mask field using strokes.

  • HeightField Patch

    Patches features from one heightfield to another.

  • HeightField Pattern

    Adds displacement in the form of a ramps, steps, stripes, Voronoi cells, or other patterns.

  • HeightField Project

    Projects 3D geometry into a height field.

  • HeightField Quick Shade

    Applies a material that lets you plug in textures for different layers.

  • HeightField Remap

    Remaps the values in a height field or mask layer.

  • HeightField Resample

    Changes the resolution of a height field.

  • HeightField Scatter

    Scatters points across the surface of a height field.

  • HeightField Slump

    Simulates loose material sliding down inclines and piling at the bottom.

  • HeightField Terrace

    Creates stepped plains from slopes in the terrain.

  • HeightField Tile Splice

    Stitches height field tiles back together.

  • HeightField Tile Split

    Splits a height field volume into rows and columns.

  • HeightField Transform

    Height field specific scales and offsets.

  • HeightField Visualize

    Visualizes elevations using a custom ramp material, and mask layers using tint colors.

  • Hole

    Makes holes in surfaces.

  • IK Chains

    Create and evaluate Two-Bone IK solvers on a SOP skeleton.

  • Inflate

    Deforms the points in the first input to make room for the inflation tool.

  • Instance

    Instances Geometry on Points.

  • Intersection Analysis

    Creates points with attributes at intersections between a triangle and/or curve mesh with itself, or with an optional second set of triangles and/or curves.

  • Intersection Stitch

    Composes triangle surfaces and curves together into a single connected mesh.

  • Invoke Compiled Block

    Processes its inputs using the operation of a referenced compiled block.

  • IsoOffset

    Builds an offset surface from geometry.

  • IsoSurface

    Generates an isometric surface from an implicit function.

  • Join

    The Join op connects a sequence of faces or surfaces into a single primitive that inherits their attributes.

  • Knife

    Divides, deletes, or groups geometry based on an interactively drawn line.

  • L-System

    Creates fractal geometry from the recursive application of simple rules.

  • LOP Import

  • Lattice

    Deforms geometry based on how you reshape control geometry.

  • Lidar Import

    Reads a lidar file and imports a point cloud from its data.

  • Line

    Creates polygon or NURBS lines from a position, direction, and distance.

  • MDD

    Animates points using an MDD file.

  • Magnet

    Deforms geometry by using another piece of geometry to attract or repel points.

  • Map Points

    Stores a reference on a point to a point in another geometry.

  • Mask by Feature

    Creates a point attribute "mask" based on visibility/lighting, letting you limit the effect of other nodes to areas that are visible, or facing a certain direction, or in shadow.

  • Match Axis

    Aligns the input geometry to a specific axis.

  • Match Size

    Resizes and recenters the geometry according to reference geometry.

  • Match Topology

    Reorders the primitive and point numbers of the input geometry to match some reference geometry.

  • Material

    Assigns one or more materials to geometry.

  • Measure

    Measures area, volume, or curvature of individual elements or larger pieces of a geometry and puts the results in attributes.

  • Merge

    Merges geometry from its inputs.

  • MetaGroups

    Defines groupings of metaballs so that separate groupings are treated as separate surfaces when merged.

  • Metaball

    Creates metaballs and meta-superquadric surfaces.

  • Mirror

    Duplicates and mirrors geometry across a mirror plane.

  • Mocap Import

    Parses and imports motion capture data as geometry.

  • MotionClip

    Converts a skeleton animation to a MotionClip

  • MotionClip Blend

    Blends the animation of one MotionClip on top of another

  • MotionClip Cycle

    Smoothly loops a section of a MotionClip

  • MotionClip Evaluate

    Evaluates a single frame of a MotionClip

  • MotionClip Extract

    Extracts the motion of joints over a set of frames from a MotionClip

  • MotionClip Pose Delete

    Removes the specified samples from the MotionClip

  • MotionClip Pose Insert

    Adds a new sample to a MotionClip containing the given pose

  • MotionClip Retime

    Adjusts the timing of a MotionClip

  • MotionClip Sequence

    Concatenates two MotionClips

  • MotionClip Update

    Update a MotionClip using the given point list

  • Mountain

    Displaces points along their normals based on fractal noise.

  • Muscle Capture

    Supports Muscle Deform by assigning capture weights to points based on distance away from given primitives

  • Muscle Deform

    Deforms a surface mesh representing skin to envelop or drape over geometry representing muscles

  • Name

    Creates a "naming" attribute on points or primitives allowing you to refer to them easily, similar to groups.

  • Normal

    Computes surface normal attribute.

  • Null

    Does nothing.

  • Object Merge

    Merges geometry from multiple sources and allows you to define the manner in which they are grouped together and transformed.

  • Object_musclerig@musclerigstrokebuilder

  • Object_riggedmuscle@musclestrokebuilder

    Assists the creation of a Muscle or Muscle Rig by allowing you to draw a stroke on a projection surface.

  • Ocean Evaluate

    Deforms input geometry based on ocean "spectrum" volumes.

  • Ocean Foam

    Generates particle-based foam

  • Ocean Source

    Generates particles and volumes from ocean "spectrum" volumes for use in simulations

  • Ocean Spectrum

    Generates volumes containing information for simulating ocean waves.

  • Ocean Waves

    Instances individual waveforms onto input points and generated points.

  • OpenCL

    Executes an OpenCL kernel on geometry.

  • Orientation Along Curve

    Computes orientations (frames) along curves.

  • Output

    Marks the output of a sub-network.

  • Pack

    Packs geometry into an embedded primitive.

  • Pack Points

    Packs points into a tiled grid of packed primitives.

  • Packed Disk Edit

    Editing Packed Disk Primitives.

  • Packed Edit

    Editing Packed Primitives.

  • Paint Color Volume

    Creates a color volume based on drawn curve

  • Paint Fog Volume

    Creates a fog volume based on drawn curve

  • Paint SDF Volume

    Creates an SDF volume based on drawn curve

  • Particle Fluid Surface

    Generates a surface around the particles from a particle fluid simulation.

  • Particle Fluid Tank

    Creates a set of regular points filling a tank.

  • Partition

    Places points and primitives into groups based on a user-supplied rule.

  • Path Deform

    Deforms geometry using the shape of a curve.

  • Peak

    Moves primitives, points, edges or breakpoints along their normals.

  • Planar Patch

    Creates a planar polygonal patch.

  • Planar Patch from Curves

    Fills in a 2d curve network with triangles.

  • Planar Pleat

    Deforms flat geometry into a pleat.

  • Platonic Solids

    Creates platonic solids of different types.

  • Point Cloud Iso

    Constructs an iso surface from its input points.

  • Point Deform

    Deforms geometry according to an arbitrary connected point mesh.

  • Point Generate

    Creates new points, optionally based on point positions in the input geometry.

  • Point Jitter

    Jitters points in random directions.

  • Point Relax

    Moves points with overlapping radii away from each other, optionally on a surface.

  • Point Replicate

    Generates a cloud of points around the input points.

  • Point Split

    Splits points shared by multiple vertices, optionally only if the vertices differ in attribute values.

  • Point Velocity

    Computes and manipulates velocities for points of a geometry.

  • Point Weld

    Merges points interactively.

  • Points from Volume

    Creates set of regular points filling a volume.

  • Poly Bridge

    Creates flat or tube-shaped polygon surfaces between source and destination edge loops, with controls for the shape of the bridge.

  • Poly Expand 2D

    Creates offset polygonal geometry for planar polygonal graphs.

  • Poly Extrude

    Extrudes polygonal faces and edges.

  • PolyBevel

    Creates straight, rounded, or custom fillets along edges and corners.

  • PolyCut

    Breaks curves where an attribute crosses a threshold.

  • PolyDoctor

    Helps repair invalid polygonal geometry, such as for cloth simulation.

  • PolyFill

    Fills holes with polygonal patches.

  • PolyFrame

    Creates coordinate frame attributes for points and vertices.

  • PolyLoft

    Creates new polygons using existing points.

  • PolyPatch

    Creates a smooth polygonal patch from primitives.

  • PolyPath

    Cleans up topology of polygon curves.

  • PolyReduce

    Reduces the number of polygons in a model while retaining its shape. This node preserves features, attributes, textures, and quads during reduction.

  • PolySoup

    Combines polygons into a single primitive that can be more efficient for many polygons

  • PolySpline

    The PolySpline SOP fits a spline curve to a polygon or hull and outputs a polygonal approximation of that spline.

  • PolySplit

    Divides an existing polygon into multiple new polygons.

  • PolyWire

    Constructs polygonal tubes around polylines, creating renderable geometry with smooth bends and intersections.

  • Pose Difference

    Compute the difference between point transforms on two SOP skeletons.

  • Pose Scope

    Assigns channel paths and/or pickscripts to geometry.

  • Pose-Space Deform

    Interpolates between a set of pose-shapes based on the value of a set of drivers.

  • Pose-Space Deform Combine

    Combine result of Pose-Space Deform with rest geometry.

  • Pose-Space Edit

    Packs geometry edits for pose-space deformation.

  • Pose-Space Edit Configure

    Creates common attributes used by the Pose-Space Edit SOP.

  • Primitive

    Edits primitive, primitive attributes, and profile curves.

  • Profile

    Extracts or manipulates profile curves.

  • Project

    Creates profile curves on surfaces.

  • Pyro Bake Volume

    Helps develop the volume look both for viewport display and rendering after the pyro solve.

  • Pyro Burst Source

    Creates points suitable for sourcing into pyro simulations to create explosions.

  • Pyro Post-Process

    Applies common post-processing effects to the results of Pyro solves.

  • Pyro Scatter from Burst

    Generates a cloud of points around the input points suitable for pyro trails and particle simulations.

  • Pyro Solver

    Runs a dynamic Pyro simulation.

  • Pyro Source

    Creates points for sourcing pyro and smoke simulations.

  • Pyro Source Spread

    Pyro Source Spread solves for the spreading of flame across a point cloud.

  • Pyro Trail Path

    Generates curves to use as trails for the Pyro Trail Source node.

  • Pyro Trail Source

    Creates points suitable for sourcing into pyro simulations to create trails for explosions.

  • Python

    Runs a Python snippet to modify the incoming geometry.

  • RBD Bullet Solver

    Runs a dynamic Bullet simulation.

  • RBD Cluster

    Combines fractured pieces or constraints into larger clusters.

  • RBD Configure

    Packs and creates attributes describing rigid body objects.

  • RBD Connected Faces

    Stores the primitive number and distance to the opposite face on the inside faces of fractured geometry.

  • RBD Constraint Properties

    Creates attributes describing rigid body constraints.

  • RBD Constraints From Curves

    Creates rigid body constraint geometry from curves drawn in the viewport.

  • RBD Constraints From Lines

    Creates rigid body constraint geometry from interactively drawn lines in the viewport.

  • RBD Constraints From Rules

    Creates rigid body constraint geometry from a set of rules and conditions.

  • RBD Convert Constraints

    Converts existing constraint prims into constraints with different anchor positions.

  • RBD Deform Pieces

    Deforms geometry with simulated proxy geometry.

  • RBD Disconnected Faces

    Detects when connected faces have become separated.

  • RBD Exploded View

    Visualize RBD fractured geometry merged with the proxy geometry, pushed out from the center to create an exploded view.

  • RBD Guide Setup

    Sets attributes on packed fragments for the RBD Guide DOP.

  • RBD I/O

    Packs RBD fractured geometry, saves them to disk, and loads them back again.

  • RBD Interior Detail

    Creates additional detail on the interior surfaces of fractured geometry.

  • RBD Material Fracture

    Fractures the input geometry based on a material type.

  • RBD Pack

    Packs RBD geometry, constraints, and proxy geometry into a single geometry.

  • RBD Paint

    Paints values onto geometry or constraints using strokes.

  • RBD Unpack

    Unpacks an RBD setup into three outputs.

  • RMan Shader

    Attaches RenderMan shaders to groups of faces.

  • ROP FBX Animation Output

    Export animation from geometry-based skeleton to an FBX file.

  • ROP FBX Character Output

    Export a skinned character with geometry-based skeleton to an FBX file.

  • ROP Geometry Output

  • Rails

    Generates surfaces by stretching cross-sections between two guide rails.

  • Ray

    Projects one surface onto another.

  • Re-Orient Joints

    Re-Orient Joints on a SOP Rig..

  • Refine

    Increases the number of points/CVs in a curve or surface without changing its shape.

  • Reguide

    Scatters new guides, interpolating the properties of existing guides.

  • Remesh

    Recreates the shape of the input surface using "high-quality" (nearly equilateral) triangles.

  • Repack

    Repacks geometry as an embedded primitive.

  • Reparent Joints

    Reparent Joints on a SOP Rig.

  • Resample

    Resamples one or more curves or surfaces into even length segments.

  • Rest Position

    Sets the alignment of solid textures to the geometry so the texture stays put on the surface as it deforms.

  • Retime

    Retimes the time-dependent input geometry.

  • Reverse

    Reverses or cycles the vertex order of faces.

  • Reverse Foot

    Creates a reverse foot set up for the given input skeleton.

  • Revolve

    Revolves a curve around a center axis to sweep out a surface.

  • Rewire Vertices

    Rewires vertices to different points specified by an attribute.

  • Rig Attribute VOP

    Runs a VOP network to modify geometry attributes on a KineFX rig.

  • Rig Attribute Wrangle

    Runs a VEX snippet to modify transform attribute values on a KineFX rig.

  • Rig Copy Transforms

    Attach the joints of a skeleton SOP to another, posed skeleton.

  • Rig Doctor

    Optimize and run checks on a SOP skeleton

  • Rig Match Pose

    Conform the rest poses of two skeletons in preparation for retargeting.

  • Rig Mirror Pose

    Mirror a SOP skeleton’s pose.

  • Rig Pose

    Pose and animate a SOP rig or skeleton.

  • Rig Python

    Runs a Python snippet to modify the incoming rig geometry.

  • Rig Stash Pose

    Store a static pose on a skeleton as a matrix point attribute.

  • Ripple

    Generates ripples by displacing points along the up direction specified.

  • Ripple

    Generates ripples by displacing points along the up direction specified.

  • Scatter

    Scatters new points randomly across a surface or through a volume.

  • Scatter and Align

    Scatters points across a surface with randomized scale and orientation attributes for use with Copy to Points.

  • Scene Character Export

    Export animation from a geometry-based character to the Scene (OBJ) context.

  • Scene Character Import

    Creates a geometry-based character with animation from the Scene (OBJ) context.

  • Script

    Runs scripts when cooked.

  • Sculpt

    Lets you interactively reshape a surface by brushing.

  • Sequence Blend

    Morphs though a sequence of 3D shapes, interpolating geometry and attributes.

  • Shape Diff

    Computes the post-deform or pre-deform difference of two geometries with similar topologies.

  • Shrinkwrap

    Computes the convex hull of the input geometry and moves its polygons inwards along their normals.

  • Skeleton

    Interactively create and edit geometry-based skeletons.

  • Skeleton Blend

    Blends two skeletons

  • Skeleton Mirror

    Modify an input skeleton by duplicating joints across a mirror plane.

  • Skin

    Builds a skin surface between any number of shape curves.

  • Sky

    Creates a sky filled with volumentric clouds

  • Smooth

    Smooths out (or "relaxes") polygons, meshes and curves without increasing the number of points.

  • Soft Peak

    Moves the selected point along its normal, with smooth rolloff to surrounding points.

  • Soft Transform

    Moves the selected point, with smooth rolloff to surrounding points.

  • Solid Fracture

    Creates a partition of a tetrahedral mesh that can be used for finite-element fracturing.

  • Solver

    Allows running a SOP network iteratively over some input geometry, with the output of the network from the previous frame serving as the input for the network at the current frame.

  • Sort

    Reorders points and primitives in different ways, including randomly.

  • Sphere

    Creates a sphere or ovoid surface.

  • Split

    Splits primitives or points into two streams.

  • Spray Paint

    Spray paints random points onto a surface.

  • Sprite

    A SOP node that sets the sprite display for points.

  • Stabilize Joint

    Removes jitter from the input animation and handles terrain snapping of joints.

  • Starburst

    Insets points on polygonal faces.

  • Stash

    Caches the input geometry in the node on command, and then uses it as the node’s output.

  • Stitch

    Stretches two curves or surfaces to cover a smooth area.

  • Stroke

    Low level tool for building interactive assets.

  • Subdivide

    Subdivides polygons into smoother, higher-resolution polygons.

  • Subnetwork

    The Subnet op is essentially a way of creating a macro to represent a collection of ops as a single op in the Network Editor.

  • Super Quad

    Generates an isoquadric surface.

  • Surfsect

    Trims or creates profile curves along the intersection lines between NURBS or bezier surfaces.

  • Sweep

    Creates a surface by sweeping a cross section curve along a spine curve.

  • Switch

    Switches between network branches based on an expression or keyframe animation.

  • Switch-If

    Switches between two network branches based on an expression or geometry test.

  • TOP Geometry

    Sends input geometry to a TOP subnet and retrieves the output geometry.

  • Table Import

    Reads a CSV file creating point per row.

  • Test Geometry: Crag

    Creates a rock creature, which can be used as test geometry.

  • Test Geometry: Pig Head

    Creates a pig head, which can be used as test geometry..

  • Test Geometry: Rubber Toy

    Creates a rubber toy, which can be used as test geometry.

  • Test Geometry: Shader Ball

    Creates a shader ball, which can be used to test shaders.

  • Test Geometry: Squab

    Creates a squab, which can be used as test geometry.

  • Test Geometry: Template Body

    Creates a template body, which can be used as test geometry.

  • Test Geometry: Template Head

    Creates a template head, which can be used as test geometry.

  • Test Geometry: Tommy

    Creates a soldier, which can be used as test geometry.

  • Test Simulation: Crowd Transition

    Provides a simple crowd simulation for testing transitions between animation clips.

  • Test Simulation: Ragdoll

    Provides a simple Bullet simulation for testing the behavior of a ragdoll.

  • Tet Conform

    Creates a tetrahedral mesh that conforms to a connected mesh as much as possible.

  • Tet Embed

    Creates a simple tetrahedral mesh that covers a connected mesh.

  • Tet Partition

    Partitions a given tetrahedron mesh into groups of tets isolated by a given polygon mesh

  • TimeShift

    Cooks the input at a different time.

  • Toon Shader Attributes

    Sets attributes used by the Toon Color Shader and Toon Outline Shader.

  • Topo Transfer

    Non-rigidly deforms a surface to match the size and shape of a different surface.

  • TopoBuild

    Lets you interactively draw a reduced quad mesh automatically snapped to existing geometry.

  • Torus

    Creates a torus (doughnut) shaped surface.

  • Trace

    Traces curves from an image file.

  • Trail

    Creates trails behind points.

  • Transform

    The Transform operation transforms the source geometry in "object space" using a transformation matrix.

  • Transform Axis

    Transforms the input geometry relative to a specific axis.

  • Transform By Attribute

    Transforms the input geometry by a point attribute.

  • Transform Pieces

    Transforms input geometry according to transformation attributes on template geometry.

  • Tri Bezier

    Creates a triangular Bezier surface.

  • TriDivide

    Refines triangular meshes using various metrics.

  • Triangulate 2D

    Connects points to form well-shaped triangles.

  • Trim

    Trims away parts of a spline surface defined by a profile curve or untrims previous trims.

  • Tube

    Creates open or closed tubes, cones, or pyramids.

  • USD Animation Import

    Imports a skeleton and animation from a UsdSkel character.

  • USD Character Import

    Imports the rest geometry, skeleton, and animation from a UsdSkel character.

  • USD Skin Import

    Imports skinned geometry from a UsdSkel character.

  • UV Autoseam

    Generates an edge group representing suggested seams for flattening a polygon model in UV space.

  • UV Brush

    Adjusts texture coordinates in the UV viewport by painting.

  • UV Edit

    Lets you interactively move UVs in the texture view.

  • UV Flatten

    Creates flattened pieces in texture space from 3D geometry.

  • UV Fuse

    Merges UVs.

  • UV Layout

    Packs UV islands efficiently into a limited area.

  • UV Pelt

    Relaxes UVs by pulling them out toward the edges of the texture area.

  • UV Project

    Assigns UVs by projecting them onto the surface from a set direction.

  • UV Quick Shade

    Applies an image file as a textured shader to a surface.

  • UV Texture

    Assigns texture UV coordinates to geometry for use in texture and bump mapping.

  • UV Transform

    Transforms UV texture coordinates on the source geometry.

  • UV Unwrap

    Separates UVs into reasonably flat, non-overlapping groups.

  • Unix

    Processes geometry using an external program.

  • Unpack

    Unpacks packed primitives.

  • Unpack Points

    Unpacks points from packed primitives.

  • Unpack USD

    Converts "packed USD" primitives into normal Houdini geometry.

  • VDB

    Creates one or more empty/uniform VDB volume primitives.

  • VDB Activate

    Activates voxel regions of a VDB for further processing.

  • VDB Activate SDF

    Expand or contract signed distance fields stored on VDB volume primitives.

  • VDB Advect

    Moves VDBs in the input geometry along a VDB velocity field.

  • VDB Advect Points

    Moves points in the input geometry along a VDB velocity field.

  • VDB Analysis

    Computes an analytic property of a VDB volumes, such as gradient or curvature.

  • VDB Clip

    Clips VDB volume primitives using a bounding box or another VDB as a mask.

  • VDB Combine

    Combines the values of two aligned VDB volumes in various ways.

  • VDB Diagnostics

    Tests VDBs for Bad Values and Repairs.

  • VDB Fracture

    Cuts level set VDB volume primitives into multiple pieces.

  • VDB LOD

    Build an LOD Pyramid from a VDB.

  • VDB Morph SDF

    Blends between source and target SDF VDBs.

  • VDB Occlusion Mask

    Create a mask of the voxels in shadow from a camera for VDB primitives.

  • VDB Points Delete

    Deletes points inside of VDB Points primitives.

  • VDB Points Group

    Manipulates the Internal Groups of a VDB Points Primitive.

  • VDB Potential Flow

    Computes the steady-state air flow around VDB obstacles.

  • VDB Project Non-Divergent

    Removes divergence from a Vector VDB.

  • VDB Renormalize SDF

    Fixes signed distance fields stored in VDB volume primitives.

  • VDB Resample

    Re-samples a VDB volume primitive into a new orientation and/or voxel size.

  • VDB Reshape SDF

    Reshapes signed distance fields in VDB volume primitives.

  • VDB Segment by Connectivity

    Splits SDF VDBs into connected components.

  • VDB Smooth

    Smooths out the values in a VDB volume primitive.

  • VDB Smooth SDF

    Smooths out SDF values in a VDB volume primitive.

  • VDB Topology to SDF

    Creates an SDF VDB based on the active set of another VDB.

  • VDB Vector Merge

    Merges three scalar VDB into one vector VDB.

  • VDB Vector Split

    Splits a vector VDB primitive into three scalar VDB primitives.

  • VDB Visualize Tree

    Replaces a VDB volume with geometry that visualizes its structure.

  • VDB from Particle Fluid

    Generates a signed distance field (SDF) VDB volume representing the surface of a set of particles from a particle fluid simulation.

  • VDB from Particles

    Converts point clouds and/or point attributes into VDB volume primitives.

  • VDB from Polygons

    Converts polygonal surfaces and/or surface attributes into VDB volume primitives.

  • VDB to Spheres

    Fills a VDB volume with adaptively-sized spheres.

  • Vellum Brush

    Interactive brushing of Vellum geometry in the viewport.

  • Vellum Configure Grain

    Configures geometry for Vellum Grain constraints.

  • Vellum Constraint Property

    Modifies common Vellum Constraint properties.

  • Vellum Constraints

    Configure constraints on geometry for the Vellum solvers.

  • Vellum Drape

    Vellum solver setup to pre-roll fabric to drape over characters.

  • Vellum I/O

    Packs Vellum simulations, saves them to disk, and loads them back again.

  • Vellum Pack

    Packs Vellum geometry and constraints into a single geometry.

  • Vellum Post-Process

    Applies common post-processing effects to the result of Vellum solves.

  • Vellum Reference Frame

    Ties Vellum points to a reference frame defined by moving geometry.

  • Vellum Rest Blend

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

  • Vellum Solver

    Runs a dynamic Vellum simulation.

  • Vellum Unpack

    Unpacks a Vellum simulation into two outputs.

  • Verify BSDF

    Verify that a bsdf conforms to the required interface.

  • Vertex

    Manually adds or edits attributes on vertices (rather than on points).

  • Visibility

    Shows/hides primitives in the 3D viewer and UV editor.

  • Visualize

    Lets you attach visualizations to different nodes in a geometry network.

  • Visualize Rig

    Visualize the transformations and parenting of a SOP skeleton

  • Volume

    Creates a volume primitive.

  • Volume Analysis

    Computes analytic properties of volumes.

  • Volume Arrival Time

    Computes a speed-defined travel time from source points to voxels.

  • Volume Blur

    Blurs the voxels of a volume.

  • Volume Bound

    Bounds voxel data.

  • Volume Break

    Cuts polygonal objects using a signed distance field volume.

  • Volume Compress

    Re-compresses Volume Primitives.

  • Volume Convolve 3×3×3

    Convolves a volume by a 3×3×3 kernel.

  • Volume FFT

    Compute the Fast Fourier Transform of volumes.

  • Volume Feather

    Feathers the edges of volumes.

  • Volume Merge

    Flattens many volumes into one volume.

  • Volume Mix

    Combines the scalar fields of volume primitives.

  • Volume Optical Flow

    Translates the motion between two "image" volumes into displacement vectors.

  • Volume Patch

    Fill in a region of a volume with features from another volume.

  • Volume Ramp

    Remaps a volume according to a ramp.

  • Volume Rasterize

    Rasterizes into a volume.

  • Volume Rasterize Attributes

    Samples point attributes into VDBs.

  • Volume Rasterize Curve

    Converts a curve into a volume.

  • Volume Rasterize Hair

    Converts fur or hair to a volume for rendering.

  • Volume Rasterize Particles

    Converts a point cloud into a volume.

  • Volume Rasterize Points

    Converts a point cloud into a volume.

  • Volume Reduce

    Reduces the values of a volume into a single number.

  • Volume Resample

    Resamples the voxels of a volume to a new resolution.

  • Volume Resize

    Resizes the bounds of a volume without changing voxels.

  • Volume SDF

    Builds a Signed Distance Field from an isocontour of a volume.

  • Volume Slice

    Extracts 2d slices from volumes.

  • Volume Splice

    Splices overlapping volume primitives together.

  • Volume Stamp

    Stamps volumes instanced on points into a single target volume.

  • Volume Surface

    Adaptively surfaces a volume hierarchy with a regular triangle mesh.

  • Volume Trail

    Computes a trail of points through a velocity volume.

  • Volume VOP

    Runs CVEX on a set of volume primitives.

  • Volume Velocity

    Computes a velocity volume.

  • Volume Velocity from Curves

    Generates a volume velocity field using curve tangents.

  • Volume Velocity from Surface

    Generates a velocity field within a surface geometry.

  • Volume Visualization

    Adjusts attributes for multi-volume visualization.

  • Volume Wrangle

    Runs a VEX snippet to modify voxel values in a volume.

  • Volume from Attribute

    Sets the voxels of a volume from point attributes.

  • Voronoi Adjacency

    Create a line segment between points with adjacent Voronoi cells

  • Voronoi Fracture

    Fractures the input geometry by performing a Voronoi decomposition of space around the input cell points

  • Voronoi Fracture Points

    Given an object and points of impact on the object, this SOP generates a set of points that can be used as input to the Voronoi Fracture SOP to simulate fracturing the object from those impacts.

  • Voronoi Split

    Cuts the geometry into small pieces according to a set of cuts defined by polylines.

  • Vortex Force Attributes

    Creates the point attributes needed to create a Vortex Force DOP.

  • Whitewater Source

    Generates volumes to be used as sources in a whitewater simulation.

  • Winding Number

    Computes generalized winding number of surface at query points.

  • Wire Blend

    Morphs between curve shapes while maintaining curve length.

  • Wire Capture

    Captures surfaces to a wire, allowing you to edit the wire to deform the surface.

  • Wire Deform

    Deforms geometry captured to a curve via the Wire Capture node.

  • Wire Transfer

    Transfers the shape of one curve to another.

  • Wireframe

    Constructs polygonal tubes around polylines, creating renderable geometry.

  • glTF ROP output driver