Houdini 20.5 Nodes Render nodes

Image render node

Writes the output of a COP network to disk.

This node writes COP network outputs to disk as image files.

Parameters

Render to Disk

Saves the images to disk with the last control settings.

Render to Disk in MPlay

Renders the images to MPlay.

Render to Disk in Background

Starts another copy of Houdini in the background and instructs that copy to cook and save the images. This allows one to continue working and load the image files as they complete.

Controls…

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

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 values may be floating point values. The range is inclusive.

These parameters determine the values of the 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).

Render with Take

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

COP Path

The COP node, or COP subnet to render from.

Add AOVs from COP

Pressing this button will remove all existing AOVs and import each AOV from the specified cop and set their properties appropriately.

Output File

File path to write the rendered images to.

Compiled Cook

Controls if the input nodes will be executed as a compiled block. Disabling through this toggle is a quick way to compare compiled and non-compiled behavior.

Set Default Resolution

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

Default Resolution

Resolution of rendered images.

Set Default Pixel Scale

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

Default Pixel Scale

Pixel scale of rendered images.

Set Default Border

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

Default Border

Border of rendered images.

Set Default Precision

Turn this on to specify the precision to render with. If this is off, the node uses the COP node’s precision.

Default Precision

Precision of rendered images.

Colorspace Conversion

OpenColorIO Colorspace

Use OpenColorIO to perform the color space transformations.

Bake to OpenColorIO Display/View

Bake the output image to an OpenColorIO display and view.

Raw

Don’t perform any colorspace conversion.

Colorspace

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

Look

When Colorspace Conversion is OpenColorIO Colorspace, this is the OpenColorIO look to apply.

Display

When Colorspace Conversion is Bake to OpenColorIO 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 Colorspace Conversion is Bake to OpenColorIO 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.

Save Retries

If saving the image to disk fails due to a disk writing error, Houdini will usually error the output node immediately. This is desirable for most cases where a failure to save means an illegal path, which is not recoverable. However, sometimes files fail to save due to network issues. If the number of save retries is non-zero, Houdini will re-attempt to save this number of times. Each time will be accompanied with an output to the console of the failure to save and a five second wait in the hopes that the network will clear up.

Reload All Files

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

File Layout

AOV Name

The name of the COP output to write to disk.

Data Size

Data size of output AOV.

Raw

Don’t perform any colorspace conversion on this AOV.

Explicit Port

When enabled, allows you to explicity specify the output port index of the source COP.

Port

The output port index of the AOV on the source COP. If you add your AOVs in non-sequential order, you must use this parameter to specify the correct order.

For instance, the AOVs in your source COP are C, N, P, and you add them to the Image ROP as P, C, N, you will need to set the port parameters to 2, 0, 1, respectively.

Render Settings

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.

Alfred Style Progress

A percentage complete value is printed out as files are written. This is in the style expected by Pixar’s Alfred render queue.

Save in Background

When saving more than one frame, save in a background thread. This can make saving faster for large file sizes, but may use more memory since it will retain the output image until the save completes.

Metadata

Artist

Houdini render property
vm_image_artist

The name of the image creator. By default uses the current user’s log in name.

Houdini, TIFF, PNG formats

Comment

Houdini render property
vm_image_comment

A text comment to include in the output file.

Houdini, OpenEXR, PNG formats

Hostname

Houdini render property
vm_image_hostname

The name of the computer where this image was created.

MPlay session label

Houdini render property
vm_image_mplay_label

When rendering to MPlay, all Houdini sessions will send the output to the same MPlay flipbook. This can be problematic when running multiple Houdini sessions. The MPlay Label lets you specify a label for the MPlay associated with the output driver. Only renders which match the given label will be sent to that MPlay.

Houdini Process ID

Uses the operating system process identifier so that the MPlay flipbook will only accept renders from that Houdini session.

HIP Name

Uses the $HIPNAME variable so the MPlay will only accept renders from the running $HIP file.

Output Driver Name

The MPlay flipbook will only accept renders from the given output driver. For example, if you copy paste the output driver, each output driver will be sent to different MPlay flipbooks because the operators will have different names.

If there are multiple Houdini sessions, there may be output drivers in the other session which match the same operator name.

For example, say you have two output drivers: “High quality” and “Low Quality”. If you set the MPlay Label to different values for the two output drivers, each render will be sent to different MPlay sessions.

MPlay gamma

Houdini render property
vm_image_mplay_gamma

Display gamma for MPlay, from 0.0 to 4.0.

JPEG quality

Houdini render property
vm_image_jpeg_quality

JPEG Quality, integer from 10 to 100.

TIFF compression

Houdini render property
vm_image_tiff_compression

Type of image compression to use in TIFF files. Possible values are "None", "LZW", "AdobeDeflate", "Deflate", "PackBits", "JPEG", "PixarLog", "SGILog", "SGILog24".

EXR Compression

Houdini render property
vm_image_exr_compression

Compression type for EXR format images. Possible values are "none", "rle", "zips", "zip", "piz", "pix", "b44", "b44a", "dwaa", "dwab".

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.

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.

  • 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