Houdini 20.0 Nodes Render nodes

Agent render node

This output operator is used to write agent definition files.

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Since 14.0

This output operator is used to write files that define an agent. The created files can then be loaded in by the Agent geometry node to create agent primitives for crowds.


Agent primitives currently only support deforming point normals and not vertex normals. When the deforming geometry is written out, vertex normals will be automatically promoted to point normals as a result.



Begins the render with the last render control settings.


Opens the render control dialog to allow adjustments of the render parameters before rendering.

Valid Frame Range

What frames to render.

Render Current Frame

Allow the baking any and all frames.

Render Frame Range

Only bake the frames in the range set below, but allow the baking other frames if they are referenced by in-range frames.

Render Frame Range Only (Strict)

Only bake the frames in the range set below, and don’t allow baking of other frames, even if they are referenced by in-range frames.


The range of frames for the clip (start frame, end frame, and increment), inclusive.

All values may be decimal (for example, start on frame 1.5)..

Render with Take

Uses the settings in a particular take while rendering. Choose Current to use the current take when rendering.


Specifies the source of the agent definition that will be written to disk.

Character Rig

Generate an agent definition from a character rig in the scene.

Agent Primitive

Use the agent definition from an existing agent primitive.


Generate an agent definition from an FBX file containing a character.

Character Rig

Path to the object subnetwork containing the character rig.

Traverse Outputs

When enabled, the Character Rig path is used to specify which nodes to import by traversing its outputs instead of its children.


Pattern used to limit which nodes should be imported. Patterns using usual opglob syntax along with @bundle references are accepted.


Relative paths specified here are relative to this node, not to the Character Rig.


Optional mask to further restrict which object node types will be imported. Disable the toggles to prevent baking particular types.

SOP Path

Specifies a SOP network that contains an agent primitive.

FBX File

Filename of the FBX file to generate agents from.

Import Principled Shader Values

When enabled, create material_override attribute inside the shape geometry which imports the material values from the FBX that are suitable for use with Houdini’s Principled Shader material.


In order to get accurate texture paths, this causes the FBX file to be imported with “Extract Embedded Data” enabled, which will cause .fbm directories on disk to be created with the textures extracted within them.

Convert Units

Specifies whether to convert to Houdini units when importing the FBX file.

Minimal Nodes

Only import objects whose display flags are on. If you turn this off, all nodes in the character rig are imported into the animation clip.

Keep Transforms for Deforming Shapes

When Minimal Nodes is enabled, specifies whether nodes containing deforming geometry are included in the agent’s rig and clips.

Convert to Polygon Soups

Combine polygon primitives into polygon soup primitives when creating the shape library. This can reduce memory usage, particularly when rendering with Mantra.

Load as Polygon Soups

Create polygon soup primitives instead of polygon primitives when loading geometry from the FBX file. This can reduce memory usage, particularly when rendering with Mantra.

Include Unused Capture Regions

When importing a skinned mesh, additional capture regions with identity transforms are added to the boneCapture attribute for the ancestor joints of any captured joints. It is recommended to only enable this option for compatibility with older scene files, as it can introduce issues with unpacking or merging the rest geometry of multiple skinned shapes.

Layer Name

The default layer for the agent, created using the display flags of the objects. Every agent must have at least one layer.

Bounds Scale

Specifies a scale for the bounding box of each shape in the default layer. See the Agent Primitive help page for more information on how an agent’s bounding box is computed.

Generate Collision Layer

Generate a collision layer from geometry containing capture/deform weights. This generates capture region primitives and assigns them to the corresponding bones in the rig.

Collision Layer Name

When Generate Collision Layer is on, the name of the collision layer.

Clip Name

Name of the baked out clip (agent animation). The animation is taken from the current scene.

Clip Name

Specifies the names of the animation clip(s). A clip is created for each take in the FBX file. The ${FBX_TAKE_NAME} and ${FBX_TAKE_INDEX} local variables can be used to generate clip names based on the take name and index from the FBX file.

Override Sample Rate

Specifies whether to use the value of the Sample Rate parameter instead of the sample rate stored in the FBX file. This is useful if the application that exported the original FBX file did not set the sample rate correctly.

Sample Rate

Sample rate to use for the clip when Override Sample Rate is enabled.

Additional Channels

Adds channels from the specified CHOP node to the agent’s clip.

Shift Clip to Frame 1

Shift output clips from the specified frame range to start at frame 1.

Create Locomotion Joint

When enabled, this will create an extra joint named __locomotion__ which serves as a placeholder for factored out locomotion animation when Convert to In-Place Animation is enabled.

Convert to In-Place Animation

Convert a moving character animation to an in-place clip, by subtracting the positions of the Locomotion Node (relative to the origin or where it was on the first frame depending on Use Pivot from First Frame parameter).

Locomotion Node

The object inside the Character Rig that controls the locomotion of the character (the node in the character rig that has translation channels that move it forward in space). When Convert to In-Place Animation, Houdini uses this to remove the translation from the character animation to keep the character in place. (The crowd solver node assumes that the agent animation is in-place since it will be attached to a moving particle.)

The locomotion animation is placed in a separate transform in the rig named __locomotion__. If this parameter is empty, then __locomotion__ will use the Character Rig.

Locomotion Orient

If this parameter and Locomotion Node are specified, the generated __locomotion__ transform will also contain rotational information using the vector from the Locomotion Node to the Locomotion Orient node. If this transform is the same as the Locomotion Node, its orientation will be directly extracted. This parameter has no effect if Locomotion Node is empty.

Project Positions on Dominant Axis

When creating the animation of the Locomotion Node, project the positions along the dominant axis of motion in the XZ plane. If the clip will be used as an in-place clip with the crowd solver, enabling this option can help to maintain hip swaying in the motion.

Use Pivot from First Frame

When creating the animation of the Locomotion Node, calculate the positions to be relative to the origin. If this option is disabled (the default), then the positions will be relative to where it was on the first frame.

Agent Name

Name of the agent. The parameter is provided for convenience so that it can be referenced via the $AGENT local variable in other parameter values.

Cache Directory

Parent directory of agent definition files. This parameter is provided for convenience so that its value can be referenced via the $CACHEDIR local variable in the other filename parameters.


Filename for the agent rig. The rig file is a JSON file describing the transform hierarchy of the agent.

Agent Layers

Filename pattern for agent layer files. The ${LAYER} local variable can be used to the include the name of the layer in the filename.

Shape Library

Filename for the agent shape library.


Filename pattern for agent clip files. The ${CLIP} local variable can be used to the include the name of the clip in the filename.

Transform Groups

Filename pattern for agent transform group files. The ${TRANSFORM_GROUP} local variable can be used to include the name of the transform group in the filename.


Filename pattern for the agent definition’s metadata, which is a JSON file containing additional custom data.

Create Intermediate Directories

When turned on, creates intermediate parent directories for output files as needed. Currently only applies to generated scripts, images, and shadow maps.

Pre-Render Script

Execute this script before any baking.

Post-Render Script

Execute this script after all baking



The name of agent. The value either comes from the agentname string attribute on the input points when Allow Attributes to Override is enabled, or from the value of the Agent Name parameter.


A local variable provided for convenience so that the value of the Cache Directory parameter can be easily referenced.


Contains the name of the current layer when evaluating the Agent Layers parameter.


Contains the name of the current clip when evaluating the Clips parameter.


Contains the name of the current transform group when evaluating the Transform Groups filename parameter.


Contains the name of the current take in the FBX file when evaluating the Clip Name parameter and Source is FBX.


Contains the index of the current take in the FBX file when evaluating the Clip Name parameter and Source is FBX.

See also

Render nodes

  • Agent

    This output operator is used to write agent definition files.

  • Alembic

    Exports the scene to an Alembic archive. Alembic is a common exchange format for moving geometry and animation between different 3D software packages.

  • Archive Generator

    Generates disk-based archives which can be used by either mantra or RIB renderers.

  • Bake Animation

    Bakes animation from object transforms and CHOP overrides.

  • Bake Texture

    Generates a texture map from one or more objects' rendered appearance.

  • Batch

    Renders the input ROP in a single batch job.

  • Channel

    The Channel output operator generates clip files from a particular CHOP.

  • Composite

    Renders images from a compositing network.

  • DSM Merge

    Merges two or more deep shadow/camera map files.

  • Dem Bones Skinning Converter

    Converts any non-changing topology deforming mesh sequence into a bone-based animation.

  • Dynamics

    Saves the state of a DOP network simulation into files.

  • Fetch

    Makes a dependency link to a ROP in a different network.

  • Filmbox FBX

    Exports entire scenes to FBX files.

  • Filmbox FBX Animation

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

  • Filmbox FBX Character

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

  • Frame Container

    Prevents frame dependency changes in the contained nodes from affecting its inputs.

  • Frame Depedency

    Allows an output frame to depend on one or more input frames.

  • GLTF Character

  • Geometry

    Generates geometry files from a SOP or DOP network.

  • Geometry Raw

    Generates raw binary files from a SOP or DOP network.

  • HQueue Render

    HQueue, or Houdini Queue, is a distributed job scheduling system.

  • HQueue Simulation

    HQueue, or Houdini Queue, is a distributed job scheduling system.

  • Hair Card Texture

    Renders hair textures for use on hair cards.

  • Karma

    Renders non-USD scenes using Houdini’s Karma renderer.

  • Labs 3D Facebook Image

    Quickly render a 3D scene to a 2.5D image that can be uploaded to Facebook.

  • Labs Flipbook Textures

    Renders, composites, and exports flipbook textures.

  • Labs JSON Exporter

    Export geometry attibutes to a JSON file.

  • Labs Marmoset Export

    The Marmoset Export ROP allows you to quickly generate an mview inside Houdini

  • Labs Niagara ROP

    Export point caches to be used with Unreal’s Niagara particle system.

  • Labs Sketchfab

    Uploads geometry to Sketchfab

  • Labs Vertex Animation Textures

    Exports a mesh and a set of textures to be used with a shader for complex real-time effects, such as: soft-body deformation, rigid-body dynamics, dynamically remeshed geometries, and particle sprites.

  • MDD Point Cache

    This output operator is used to write an MDD animation file.

  • Mantra

    Renders the scene using Houdini’s standard mantra renderer and generates IFD files.

  • Mantra Archive

    Generates disk-based archives which can be used by mantra.

  • Merge

    Merges several render dependencies into one.

  • Net Barrier

    Blocks the ROP network until synchronization occurs.

  • Null

    Does nothing.

  • OpenGL

    Render an image using the hardware-accelerated 3D viewport renderer.

  • Pre Post

    Renders ROPs before and after a main job.

  • Shell

    Runs an external command.

  • Subnetwork

    The SubNetwork output operator provides an easy way to manage large number of output operators.

  • Switch

    Renders one of several inputs.

  • Tractor

    Tractor is a program shipped out with Pixar’s distribution of RenderMan.

  • USD

    Renders a LOP network out to one or more USD files. This node is available as render node or as a LOP.

  • USD Render

    Renders an output image from the stage generated by a LOP network.

  • USD Stitch

    Merges USD files representing individual frames by composing them.

  • USD Stitch Clips

    Merges multiple value clips representing individual frames.

  • USD Zip

    Assembles USDZ archive files from existing USD files.

  • Wedge

    Re-renders the same ROP multiple times with different settings

  • Wren

    This output operator is used to drive the Wren rendering program.

  • glTF