Houdini 20.5 Nodes Render nodes

Composite render node

Renders images from a compositing network.

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Parameters

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.

Set Valid Frame Range

Only render frames in a start/end range, at a given frame increment. This is off, the node renders every frame.

Tip

If you just want to check something, you can specify a temporary sub-range to render without changing the node. Click Render Control at the top of the parameters and specify the Frame Range there.

Composite

COP Path

Path to the COP node to render.

Override Default Res

Turn this on to specify a custom resolution to render at. If this is off, the node uses the COP node’s resolution.

Resolution

Resolution of rendered images.

Output Picture

File path to write the rendered images to.

Image Format

File format for the rendered images.

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.

Color Plane

Plane to use as the RGB channels.

Alpha Plane

Plane to use as the A channel (in RGBA image).

Output Colorspace

How to set the color space of the rendered images.

Manual Gamma/LUT: Conversion

Manually specify the gamma and lookup table file used to save images.

Autodetect from File

This uses the Houdini image library to determine the color space of the output image and transform to the appropriate space. For example, JPEG files will be saved in sRGB.

Use OpenColorIO

Use OpenColorIO to perform the color space transformations.

Bake to OpenColorIO Display/View

Color Space

When Output Colorspace is Use OpenColorIO, the output color space. The menu lists the color spaces from the OpenColorIO configuration file.

There are two additional items in the menu:

Parse Colorspace from File (automatic)

Use the OpenColorIO file parsing rules to detect the output color space by parsing the output file.

Look

When Output Colorspace is Use OpenColorIO, this is an OpenColorIO look to apply.

Display

When Output Colorspace is Use OpenColorIO and Color Space is Use OCIO Display View, this is the display to use. If this is default, the node uses the default display specified in the OpenColorIO configuration file.

View

When Output Colorspace is Use OpenColorIO and Color Space is Use OCIO Display View, this is the view for the display. If this is default, the node uses the default view for the specified display in the OpenColorIO configuration file.

Output Gamma

When Output Colorspace is Disable Colorspace Conversion, this is a manual gamma correction value to apply to images.

Output Frames Reused in Composite

Turn this on if your compositing network reads in previously completed frames to generate later frames. This disables threaded file writes and batch frame cooking.

Batch Cook Frames

Cooks frames in groups, rather than one by one. This can improve performance on multi-processor computers, for small-to-medium sized networks, which spend a higher percentage of their time preparing to cook a frame and writing the output image. This option generally makes no difference on single-processor computers. We recommend a batch size of 2, since any performance gain drops off quickly for larger batches. Batch cooking uses a bit more memory than frame-by-frame.

Reload All Files

Tell the compositing network to reload any cached files (for example, images loaded by the File COP).

Image Area

Output Area

The area of the rendered frame to write to the output file. For file formats that support “data window” or “crop” features such as OpenEXR, TIFF, and Houdini .pic, the node will use that feature. If the file format does not support this feature, the given area will be clipped from the rendered frame, and any pixels outside the area will be black.

Frame

Render the full frame, will no cropping/clipping.

Crop Region

Crop to the sub-region specified below.

Frame + Surrounding Canvas

Render the total frame and areas outside the frame, then “crop” to the frame size. This can be useful for having “extra” imagery available “outside” the frame for compositing operations such as blur. If the crop area is smaller than the frame, this option will write the full frame.

Pixel / UV Crop

The left, bottom, right, and top of the crop region, in either pixels or UV coords.

Limit Canvas Pixels

When Output Area is Frame + Surrounding Canvas and this is on, limit the extra canvas to this many pixels to the left/right/above/below the frame area. This can help prevent accidentally writing out giant files.

Limit Canvas Percent

When Output Area is Frame + Surrounding Canvas and this is on, limit the extra canvas to percentage of the width and a percentage of the height of the full frame. For example, for a 640×480 image, set this to 10% would limit the extra area to 64 pixels on the left and right, and 48 pixels on the top and bottom. This can help prevent accidentally writing out giant files.

Auxiliary File 1-5

These parameters let you save planes into separate files.

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.

Locals

N

Frame being rendered.

NRENDER

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.

  • Flipbook

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

  • 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.

  • Image

    Writes the output of a COP network to disk.

  • 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