Since 17.0

The glTF ROP can export your scene as a GLTF file. See the following link for further information about the glTF format.

The glTF ROP can do the following:

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.

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

Render with Take

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

Output File

The path of the file to generate. The extension determines the type of file to generate.

A path with a .glb extension generates a single binary GLB file and stores all resources internally.

A path with a .gltf extension may store some resources externally. Exported resources are stored in the same folder as the file and are referenced relatively.

Export Type

The file format to export.

Detect From Filename

The file format is dependent on the extension in Output File.

glTF

Export as a file with the .gltf format, and store some resources externally.

glb

Export as a single binary file with the .glb format.

Create Intermediate Directories

When turned on, creates intermediate directories for the output file if the specified Output File path contains directories that do not yet exist. For example, if you specify $HIP/output/gltf_output/owl/tropical_screech.gltf as the Output File path, and the /gltf_output and /owl directories do not exist, then the /gltf_output and /owl directories will be created automatically when you export your character.

When turned off, and the Output File path contains directories that do not exist, then the export will silently fail.

Use SOP Path

When turned on, exports a single geometry detail specified in SOP Path instead of exporting objects contained under a root object.

SOP Path

The path to the geometry detail to include in the glTF scene.

Root Object

The root object of the scene. All objects contained under this node will be included in the glTF scene.

Objects

A pattern/bundle of objects to include in the glTF scene.

Force Objects

The objects that match the names or patterns of this parameter should always appear in the scene, even if their display flag is off.

Note

This overrides the Objects and Exclude Objects parameters.

Exclude Objects

Do not include objects in the scene if they match the names or patterns given by this parameter. This overrides the Objects parameter.

Texture Source

Controls the origin of the textures that are included in the exported GLTF file.

Export from Material

New texture images will be exported based on the parameters of the material shader and the parameters on the GLTF output node.

Copy Original Textures

Any supported texture images specified in the material shader will be copied directly to the exported GLTF file, preserving the exact images that were used to build the material.

Texture Format

Controls the file format of the exported material textures.

Original Format or PNG

Textures will be exported in their original formats or as a PNG if a texture’s format is not specified or is unsupported by GLTF.

Original Format or JPEG

Textures will be exported in their original formats or as a JPEG if a texture’s format is not specified or is unsupported by GLTF.

PNG

Textures will be exported as PNGs.

JPEG

Textures will be exported as JPEGs.

Texture Quality

The level of compression to apply to outputted textures. Only applies to lossy image formats (Texture Format is set to Original Format or JPEG or JPEG).

Max Texture Resolution

If any texture is larger than this resolution, then downsize it to this resolution. Useful for quickly reducing the file size.

Rescale Texture as Power of Two

When turned on, rescales exported images so that the final image has dimensions that are powers of two (for example, 512×1024, 2048×2048).

This is required by some low-spec glTF implementations as well as WebGL implementations in older browsers.

Animation Name

The name of the exported animation.

Flip Normal Map Y

When turned on, inverts the y-coordinate on the normal texture map for each exported mesh. glTF’s orientation expects an upwards facing y-axis.

Cull Empty Nodes

When turned on, any object node with no descendants containing geometry is ignored.

Export Custom Attributes

When turned on, all public attributes are exported. When turned off, only attributes defined in the glTF standard are exported.

Attributes are exported with their original types whenever possible. However, glTF allows a maximum of 32 bits for floats and integers. Integers are also required to be unsigned. Attempting to export a datatype larger than this will narrow the type and print a warning.

Exported custom attribute names are the original names plus an _ (underscore) prefix.

As glTF only supports point attributes, name collisions will be resolved using the normal attribute resolution order.

Export Node Names

Assigns Houdini node names to the name field of glTF objects. The name attribute on packed primitives will also be exported.

Names are assigned to materials, transformation nodes, and geometry.

Export Mesh Names

When turned on, mesh names will be exported to the GLTF mesh name fields. The Mesh Names Source parameter controls the naming of the mesh.

Mesh Names Source

Node Name

The GLTF mesh name will be assigned the name of the SOP node of the exported mesh.

Attribute

The GLTF mesh name will be assigned the name stored in the attribute specified by the Mesh Name Attribute parameter. It can be any type of attribute, but it must have a consistent value.

Mesh Name Attribute

The name of the attribute that contains the mesh name’s value.

Export Materials

When turned on, this option exports Principled Shader materials. Materials are exported as a combination of emissive maps, normal maps, and pbrMetallicRoughness materials. All associated textures and images used by the material are exported alongside the material. Some Principled Shader options such as ambient occlusion and subsurface scattering are not exported.

Materials that do not use the Principled Shader will be ignored.

Export Cameras

When turned on, includes camera objects matching the Objects pattern/bundle in the glTF scene.

Export Lights

When turned on, includes light objects matching the Objects pattern/bundle in the glTF scene.

Importers for this scene will need to support the KHR_lights_punctual glTF extension in order to include the lights. This extension only supports 3 light types: directional, point, and spot.

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.

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

    The Vertex Animation Textures ROP will export 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