Houdini 20.0 Nodes Render nodes

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Save to Disk

Begins the render with the last render control settings.

Controls

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.

Render

Begins the render with the last render control settings.

Controls

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

Standard

Camera

The camera to render the scene from.

Visible Objects

Space-separated list of objects which will be rendered. Use * to render all objects (the default). You can use wildcards (for example prop_*) and bundle references to specify objects.

Visible atmosphere

Space-separated list of atmosphere objects which will be rendered. Use * to render all atmosphere objects (the default). You can use wildcards (for example fog_*) and bundle references to specify atmosphere objects.

Active Lights

Space-separated list of lights which will illuminate the scene. Use * to use all lights. You can use wildcards (for example key_*) and bundle references to specify lights.

Unload SOPs

Unload SOP geometry after used by the render.

Output Picture

The picture or device to be rendered.

Image Format

The file format (for example, Houdini pic) of the rendered image.

Valid Frame Range

Controls whether this render node outputs the current frame or the image sequence specified in the Start/End/Inc parameters.

Render Current Frame

Export only the current frame.

Render Frame Range

Export the frames in the Start/End/Inc frame range, but also allow exporting of frames referenced by in-range frames.

Render Frame Range Only (Strict)

Only export the frames in the Start/End/Inc frame range. Do not allow exporting of other frames, including frames referenced by in-range frames.

Start/End/Inc

Specifies the range of frames to render (start frame, end frame, and increment). All of the values can be floating point values. The range is inclusive.

The Start/End/Inc parameters determine the values of the below local variables for the output driver.

$NRENDER

The number of frames to be rendered by the output driver.

$N

The current frame being rendered (starting at 1 and going to $NRENDER).

For example, if the parameters are set to:

Start

End

Inc

10.5

12

0.5

… there will be 4 frames rendered (10.5, 11, 11.5, and 12), so $NRENDER will have a value of 4.

$N will have the following values at each frame:

Frame

$N

10.5

1

11

2

11.5

3

12

4

Axis System

Determines the axis system convention.

Y Up (Right-handed)

Right-handed Y Up convention (default): Up = +Y, Front = +Z, Cross = +X. Use this for Houdini, Maya Y-Up, MotionBuilder, and OpenGL.

Y Up (Left-handed)

Left-handed Y Up convention: Up = +Y, Front = +Z, Cross = -X. Use this for LightWave and DirectX.

Z Up (Right-handed)

Right-handed Z Up convention: Up = +Z, Front = -Y, Cross = +X. Use this for Maya Z-Up and 3ds Max.

Current (Y Up or Z Up Right-handed)

Export using the current scene orientation preference.

Convert to Specified Axis System

When turned on, the FBX scene will be converted from the current Houdini scene orientation to the one specified in Axis System.

Compute Smoothing Groups

When turned on, computes smoothing group information from a mesh’s vertex-mapped normals, and saves to FBX on export.

These normals can be configured on your geometry using the Normal SOP. By setting the Normal SOP’s Add Normals to parameter to Vertices, weighted/split normals can be applied to different polygon groups to specify the soft/hard edge data used to compute smoothing group information. Applying the vertex normals to primitives or edges (set Group Type to Primitives or Edges) and configuring the Cusp Angle results in the expected smoothing data in your output FBX.

Initialize Sim. SOPs

Force all simulation SOPs to be reset.

Generate Script File

Outputs an .ifd file instead of piping the script to mantra.

Binary Script File

Toggles between ascii and binary file formats.

Script File

Filename of the .ifd file.

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

Controls quality of anti-aliasing.

Decouple Ray Sample

Specify an alternate sampling rate for ray tracing. Ray sampling will use this value as a maximum sampling rate, and will take fewer samples if there is low variance.

Note

Decoupled ray sampling is only meaningful for micropolygon rendering. It will be ignored when mantra is run in ray tracing mode.

Resolution

Override camera resolution with values specified.

Pixel Aspect

Override camera pixel aspect ratio.

Fields

Control for rendering video fields.

Motion Blur

Specifies whether motion blur is allowed. If set to set to disallow, motion blur is globally turned off regardless of individual object settings.

Motion Blur Type

The default motion blur type for rendering. This can be overridden by an individual object.

Depth of Field

Turn on rendering of depth of field effects.

Jitter

Limits the amount of jitter. A value of 0 will result in no jitter.

Dither

Controls the amount of dithering performed.

Gamma

Gamma correction factor used.

Scripts

A script command can be specified for execution at various execution points. The expression language selected for the script parameter determines whether the command is in hscript or python.

Prior to execution, this node is automatically set as the global current node.

To run statements from a file, specify the path to the file with either a .cmd extension (when the language is set to Hscript) or a .py extension (when the language is set to Python). Additional arguments to the script can also be supplied. They will be parsed in a shell-like manner.

Pre-Render Script

Run this script before any rendering.

Pre-Frame Script

Run this script before each frame.

Post-Frame Script

Run this script after each frame.

Post-Render Script

Run this script after all rendering.

Extra parameters

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.

Skip Existing Frames

Skip rendering of existing frames. There are three values for this parameter.

Overwrite existing frames

This option will render every frame, regardless whether there’s a file on disk or not.

Skip frames that exist

If there’s a disk file that matches the vm_picture parameter, no render will be performed.

Skip frames that are valid images

If a disk file exists, the integrity of the image is checked before rendering is performed. This option incurs the cost of reading the image, but will re-render images that weren’t fully 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