Houdini 20.0 Nodes Render nodes

Filmbox FBX render node

Exports entire scenes to FBX files.

FBX (sometimes called Filmbox) is an interchange file format for moving 3D animation data between software packages. It can contain entire scenes, including geometry, lights, cameras, NURBS, animation, and skinning.

Note

The FBX format specification generally does not support animated objects with a changing number of points or changing connectivity, such as Houdini’s particle systems or fluids. It is only possible to export these types of objects by breaking them up into individual triangles (although still within one FBX object node).

To restore these objects to their original appearance when they are brought into other packages, weld their vertices together and set all appropriate mesh edges to smooth.

To import these types of objects properly into Maya™, Maya’s FBX importer option Use FBX Framerate in Maya must be turned on.

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.

Export

The node to start exporting at. Defaults to /obj, meaning all objects and subnetworks under /obj are exported. If the node is a network, only export its contents, not the network itself.

Create Root for Subnet

When turned on, creates an extra root for the Export node when it is a subnetwork. This causes the exporting subnetwork node to be represented in the FBX file.

Output File

The file to save the geometry to (should end in .fbx).

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.

Build Hierarchy from Path Attribute

Use a primitive string attribute for creating shape nodes in the output file. Each string value is treated like a path to a shape node that the primitive is created under. Intermediate nodes are created as needed with identity transforms. If the primitive is a packed primitive, then its parent node takes the primitive transform.

Absolute filesystem prefixes are stripped from the path value (for example, op:, http:, c:, etc).

Note

This parameter is only available when used from the Geometry context or when the Export parameter is set to a Geometry object.

Note

Support for animation export is currently limited to exporting primitive transforms, and each primitive must have a unique path attribute value. There is no support for exporting to vertex caches or changing geometry topology.

Path Attribute

The name of the attribute containing the path used for Build Hierarchy from Path Attribute.

FBX

Export in ASCII

When turned on, the exported FBX file is in human-readable ASCII format. When turned off, the file is exported as a binary FBX file.

FBX SDK Version

The SDK version to use to export the FBX file.

Vertex Cache Format

The vertex cache file format that is exported.

Maya Compatible (MC)

Maya’s native vertex cache format.

3DS MAX Compatible (PC2)

Vertex cache format compatible with 3DS MAX.

Export Invisible Objects

Determines how invisible objects are exported. This is convenient if a scene contains hidden objects that are highly complex but don’t need to be exported.

As Hidden Null Nodes

Each hidden object is represented as a hidden Null node in FBX. No time is spent exporting its geometry.

As Hidden Full Nodes

Each hidden object is represented as an appropriate type in FBX. Processing time is the same as an object that is not hidden.

As Visible Full Nodes

Each hidden object is represented as an appropriate type in FBX and is made visible. Processing time is the same as an object that is not hidden.

Don’t Export

Don’t export invisible objects.

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.

Convert Units

When turned on, the FBX scene is converted from the current Houdini system units (specified in the Houdini preferences Edit ▸ Preferences ▸ Hip File Options, default meters) to the native FBX unit of centimeters.

Conversion Level of Detail

The level of detail to use when converting non-polygonal objects to polygons. Higher values increase the polygon subdivision level; lower values decrease it.

Detect Constant Point Count Dynamic Objects

When turned on, the exporter tries to detect animated objects that don’t change point count or point connectivity, and export them without breaking them into individual triangles. The same process is done to particle systems and fluids. This allows for RBD or cloth objects to be exported as a single, smooth object, while still allowing topology-changing objects to be exported.

This may fail if an object with changing point connectivity happens to have the same point count over all frames of the exported animation. In this case, Detect Constant Point Count Dynamic Objects should be turned off.

Convert NURBS and Bezier Surfaces to Polygons

When turned on, the exporter converts all NURBS and Bezier surfaces to polygonal meshes, using the level of detail to determine mesh density. Otherwise, NURBS and Bezier surfaces are exported as NURBS.

Conserve Memory at the Expense of Export Time

Only affects objects exported with vertex caches. When turned on, internal vertex positions computed during export are discarded, not cached, resulting in reduced overall memory usage. However, this increases the export time. When turned off, the exporter runs faster but uses more memory.

Export Deforms as Vertex Caches

When turned on, any geometry objects that contain Deform SOPs are exported as vertex caches with no weight information. When turned off, these nodes are exported as objects with skinning and corresponding weights.

This parameter is only available when Valid Frame Range is set to Render Frame Range or Render Frame Range Only (Strict).

Force Blend Shape Export

When turned on, Blend Shapes SOPs in geometry nodes are always exported. This could potentially result in information being lost, since any nodes that modify the geometry after Blend Shapes are ignored.

When turned off, Blend Shapes SOPs are only exported if there are no modifications to the geometry downstream from them.

Force Skin Deform Export

When turned on, Deform SOPs in geometry nodes are always exported. This could potentially result in information being lost, since any nodes that modify the geometry after Deform are ignored. Only the Bone Deform, Bone Capture and Capture Override nodes are currently supported.

When turned off, these nodes are only exported if there are no modifications to the geometry downstream from them.

Export End Effectors

When turned on, the additional end effector null nodes at the ends of each branch of a skeleton are included in the exported FBX file. This allows the FBX file to be correctly reimported into Houdini.

When turned off, the additional end effector null nodes are not included in the exported FBX file. This can be helpful when trying to reduce the number of joints exported to an FBX file, but you will not be able to reimport it back into Houdini properly, as the skeleton is effectively missing one joint/bone from each of its branches.

Embed Media

When turned on, any media files related to the scene (textures, sound, movies) are embedded in the exported file. When turned off, only relative references to the media files related to the scene are added to the exported file.

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.

Export Animation Clips (Takes)

When turned on, animation clips are exported. Clips (also called Takes in other software) are named frame ranges in your animation. This can be used to export multiple animations in a single FBX file.

This parameter is only available when Valid Frame Range is set to Render Frame Range or Render Frame Range Only (Strict).

Clip #

A string describing the animation clip.

Frame Range

The frame range of the animation clip.

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