Houdini 20.0 Nodes Render nodes

Wren render node

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

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This output operator is the wireframe renderer. The operator sets up all necessary options and then invokes the renderer. Alternatively, the output can be saved to disk as a script file to be rendered later.

When rendering postscript, the width and height of the image represent the width and height of the “paper” (in inches). Thus to render landscape mode, the width should be set to 11 and the height set to 8.5. The postscript options can be set by clicking the + button beside the render command.

Arguments may be passed to the script and variable expansion is done before calling the script.


The Wren ROP uses the linewidth attribute, if present, to determine the width of the line.


To render files readable by Adobe, you need to use the paper width and height options.


Save to Disk

Begins the render with the last render control settings.


Opens the Render Control window, which allows you to adjust the render parameters before rendering.

Render with Take

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

Valid Frame Range

If on, the render is only valid between the start and end frames, at the specified frame increment. If a frame is outside the range, or falls on a frame that isn’t included by the frame increment, the frame will not be rendered.

If off, the render is valid at any frame.


If you want to temporarily set a sub-range to render, use the 'Frame Range' parameter in the Render Control dialog (click the Render Control… button at the top of this dialog).

Output Picture

Where the output of the render should be directed.


Which camera to render the scene from.

Visible Objects

List of objects visible in the rendered scene.

Unload SOPs

Unload SOP geometry after used by the render.

Use Display SOP

Use the display (instead of render) SOP.

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.

Initialize Simulation OPs

Forces all simulation OPs to be reset. This includes DOP Networks, POP SOPs, and other OPs that cache their results.

Generate Script File

Outputs the renderer’s script file instead of feeding the data to the renderer directly.

Binary Script File

Toggles between ascii and binary file formats.

Script File

Filename of the script file to create.

Render Command

The command used to invoke the renderer. Can be modified with the popup window.

Render in Background

Continue to use Houdini while rendering.

Super Sample

Number of rays sent per pixel in x and y when antialiasing.

Override Camera Res

Allows specification of the render resolution.


Resolution to render at.

Pixel Aspect

Specifies pixel aspect ratio of the intended viewing device.


Limits the amount of jitter. A value of 0 will not produce any jitter.

Pre-Render Script

Execute this script before any rendering.

Pre-Frame Script

Execute this script before each frame

Post-Frame Script

Execute this script after each frame

Post-Render Script

Execute this script after all rendering



The current frame of the range specified. This always starts at 1.


Total number of frames being rendered.

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