Houdini 21.0 Nodes LOP nodes

Reference 2.0

References the contents of a external USD files and/or layers created by other LOP nodes into a branch of the existing scene graph tree. Can also remove or replace existing references.

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Since 19.5

Overview

This node lets you reference a tree of primitives from a different location, into your current scene graph. These other locations can be external files, other LOP nodes, or even different primitives within the same tree. Multiple references can be made to the same source, allowing you to re-use existing primitives.

See the section References Explained for details about this USD concept.

Tips

  • When an Action parameter is set to Create New Primitives, the Primitive Path must specify a single primitive path. This parameter is re-evaluated for each reference being created, and if necessary will be made unique by appending a numeric suffix.

  • When an Action parameter is set to Edit Existing Primitives, the Primitive Path is interpreted as a primitive pattern. The reference is added to every primitive that matches the pattern.

  • If the prim you specify to reference onto already has existing references, the new reference will be composed with any existing references. See the Composition ▸ Pre-Operation parameter for how to clear existing references before adding a new one.

  • The reference operations specified on this node are performed in order, so multiple references can be added to a single primitive. For example, a Create action for the multi-input might create a some new primitives, then a subsequent Inherit operation can add an inherit arc to each of these newly created reference primitives.

How to

The “target” that gets referenced onto a primitive in the scene graph tree is often in an external file, however this node can also reference a prim in the output of another LOP node.

To...Do this

Reference a prim in an external file

  1. Set the Primitive Path to the scene graph path at which the referenced prim should be attached.

  2. Set the Reference Type to Reference Files or Payload Files (see payloads for more information).

  3. Set the File Pattern to the file path of the USD file to reference in. This file path can include wild cards to match multiple files on disk, in which case a new primitive will be created for each matching file.

  4. In addition to standard wildcard matching, the File Pattern parameter can contain the special token <LASTMATCH>. When appearing after a path component with a wildcard, this token will be set to the value used to fill in that wildcard component. So if the file /tmp/assets/Book/Book.usd exists on disk, a Reference Path of /tmp/assets/*/<LASTMATCH>.usd will find the Book.usd layer. This token is very useful when your asset naming conventions involve a USD file that matches the parent directory name.

  5. Use the Reference Primitive pop-up menu if you want to choose the prim in the external file to load in.

  6. Usually you can leave Reference Primitive set to Reference Automatically Chosen Primitive. If you want to import a specific prim, change Reference Primitive to “Reference specific primitive” and enter the prim path in Reference Primitive Path.

Reference a prim from the output of a LOP node

  1. Connect the LOP node containing the stage you want to reference to this node’s multi-input.

  2. The Primitive Path will be re-evaluated for each connected input, and can include local variables which will generate a separate primitive for each input connection.

  3. For a single addition, you can set the Reference Primitive Path to the prim to import.

    If you have multiple inputs connected to this node’s multi-input:

    • You can explicitly specify the destination primitive which will hold the reference using the table at the bottom of the parameter interface. This table can also be used to specify a different times to reference each input, and a specific primitive to reference from each input.

    • You can set Reference Primitive Path to a scene graph path to import from the same prim in all inputs, or write an expression which is evaluated from each input connected to this node’s multi-input. In the expression, you can use the @input local variable ($IIDX is deprecated) for the current input index (starting at 1). (Remember that in string parameters, you must enclose expressions in backticks.)

Reference another prim in the scene graph tree in the first input

  1. Set the Primitive Path to the scene graph path at which the referenced prim should be attached.

  2. Set the Reference Type to Reference From First Input, Inherits From First Input, or Specialize From First Input, depending on the type of composition you want. See inherits and specializes for more information about how these choices differ from a simple reference.

  3. Set Reference Primitive to Reference Specific Primitive.

  4. Set Reference Primitive Path to the scene graph path of the prim you want to reference in.

Block all existing references

  1. Set the Primitive Path to the scene graph path of the prim that currently has a reference you want to block.

  2. Set the Composition ▸ Pre-Operation menu to Clear All References.

Block one existing reference

  1. Set the Primitive Path to the scene graph path of the prim with the reference you want to remove.

  2. Set the parameters to specify the reference you want to remove. For example, if you want to remove a reference to the file lamp.usd, set Reference Type to Reference Files and File pattern to lamp.usd.

  3. Set Reference Operation to Remove References.

Reference several prims from an external file

  1. Set the Reference Type to Reference Files or Payload Files (see payloads for more information).

  2. Set the File Pattern to the file path of the USD file to reference in. This file path can include wild cards to reference primitives from several files with one node.

  3. Set the Reference Primitive to Reference Specific Primitive.

  4. Set the Reference Primitive Path to /* to reference every root primitive from every file.

  5. Set the Primitive Path to /`strcat(@sourcename, @primpath)`.

Local Variables

@sourcename

The name of the file on disk (with the extension removed) or connected input to be referenced. Only set when the Parameter Order is File Pattern Evaluated Before Primitive Path.

@sourcepath

The full path of the file on disk or connected input to be referenced. Only set when the Parameter Order is File Pattern Evaluated Before Primitive Path.

@sourceindex

An incrementing number for each connected input or file being referenced by this node. Only set when the Parameter Order is File Pattern Evaluated Before Primitive Path.

@sourceprim

An incrementing number for the current multi-input connection or file if it is being referenced multiple times. Only set when the Parameter Order is File Pattern Evaluated Before Primitive Path.

@sourcenumprim

The total number of times the current multi-input connection or file will be referenced. Only set when the Parameter Order is File Pattern Evaluated Before Primitive Path.

@prim

An incrementing number for each reference created by this node, or for each prim to which a reference is being added. Available with any Parameter Order setting.

@primpath

The full path of the prim to which a reference is being added. Only set when the Parameter Order is Primitive Path Evaluated Before File Pattern.

Parameters

References

Multi-input

Multi-input

Perform the reference operations from the multi-input.

Primitive Path

In create mode, this parameter specifies a single primitive path. This is the scene graph path where the referenced branch will be attached. If this prim doesn’t exist, the node will create it. In edit mode, this parameter is a primitive pattern that will be matched against the existing primitives on the stage connected to this node’s first input. You can use local variables to control the reference primitive path.

Action

Whether this node should create new prims for the multi-input connections, or edit existing prims. Create mode will also edit a prim if it already exists, but a unique primitive name will be created automatically for each reference created for each multi-input connection. Edit mode allows for adding references to any number of existing prims.

Primitive Count

In Create New Primitives mode, the number of referencing primitives to create for each multi-input connection.

Reference Type

The type of composition arc to create to the referenced prim.

Reference Inputs

Reference in a prim from the multi-input connections.

Payload Inputs

Reference in a prim from the multi-input connections as a payload.

Make Instanceable

Mark the new or modified prims as instanceable (as in “native instancing”). This saves memory if you reference the same branch into multiple places, but makes the descendants of the referenced prim not editable. If this option is off, the prims are not explicitly marked as not instanceable. Instead, the current instanceable value on each prim is left unchanged.

Reference Primitive

Controls which prim to import from the multi-input connections.

Reference Automatically Chosen Primitive

If the referenced input connection has a default primitive set, use that. If there is no default prim, use the first Xform prim at the root. If there is no Xform prim at the root, use the first root prim of any type.

Reference Default Primitive

If the referenced input connection has a default primitive set, use that. If not, display a warning on this node.

Reference Specific Primitive

Reference in the scene graph path in the Reference Primitive Path parameter. In this mode the reference primitive specified in each row of the input table takes precedence over the value in the Reference Primitive Path parameter.

Reference Primitive Path

The scene graph path of the prim in the referenced layer that that is composed onto the stage. Contents of the referenced layer outside of this referenced primitive path will not appear on the composed stage. This parameter is only used if the Reference Primitive parameter is set to Reference Specific Primitive.

(If you set this field automaticPrim or defaultPrim, it mimics the behavior of setting Reference Primitive to Reference Automatically Chosen Primitive or Reference Default Primitive.)

File and Internal References

Number of References

This node can add multiple references to external files and primitives already in the scene, each of which can be controlled separately.

Enable

Perform the reference in this instance of the multi-parm.

Parameter Order

Set this parameter to File Pattern Evaluated Before Primitive Path to allow the use of wild cards in the File Pattern parameter. For each matching file the Primitive Path will be evaluated to generate the path of the primitive that should reference the file.

Set this parameter to Primitive Path Evaluated Before File Pattern to author a single reference on each of a set of prims, where the referenced file or prim can be a function of the prim path that will be holding the reference. For each prim matching the Primitive Path, the File Pattern and Reference Primitive Path parameter is re-evaluated, with the ability to access the current Primitive Path to generate a value specific to that primitive.

Action

Whether this node should create new prims for the multi-input connections, or edit existing prims. Create mode will also edit a prim if it already exists, but a unique primitive name will be created automatically for each reference created for each multi-input connection. Edit mode allows for adding references to any number of existing prims.

Primitive Path

In create mode, this parameter specifies a single primitive path. This is the scene graph path where the referenced branch will be attached. If this prim doesn’t exist, the node will create it. In edit mode, this parameter is a primitive pattern that will be matched against the existing primitives on the stage connected to this node’s first input. You can use local variables to control the reference primitive path.

Primitive Count

In create mode, the number of referencing primitives to create for this multiparm instance.

Reference Type

The type of composition arc to create to the referenced prim.

Reference File

Reference in a prim from an external USD file.

Payload File

Reference in a prim from an external USD file as a payload.

Reference From First Input

Reference in another prim from the scene graph tree in the first input.

Inherit From First Input

Create an “inherits” composition arc to another prim from the scene graph tree (in the first input). The inherit target need not exist yet.

Specialize From First Input

Creates a “specializes” composition arc to another prim from the scene graph tree (in the first input). The specialize target need not exist yet.

Make Instanceable

Mark the new or modified prims as instanceable (as in “native instancing”). This saves memory if you reference the same branch into multiple places, but makes the descendants of the referenced prim not editable. If this option is off, the prims are not explicitly marked as not instanceable. Instead, the current instanceable value on each prim is left unchanged.

File Pattern

When Reference Type is Reference File or Payload File, the file path to the file to reference. This parameter can contain wildcards, in which case every matching file found on disk will be added as a separate reference. In create mode, this will create a new primitive for each matching file. In edit mode, all matching files will be referenced onto every primitive matching the Primitive Path pattern.

When specifying file paths with spaces (whether that path contains wildcard characters or not), each such file must be enclosed in quotes. This parameter value is first split into tokens (separated by whitespace, accounting for quotation marks), and then each token is expanded if it has wildcard characters, or treated as a simple file path if it does not contain any wildcards. Simple file paths will be added as references even if there is no matching file found on disk.

Wildcard pattern expansions are cached so the disk is only scanned for files the first time a given pattern is expanded on this node. This wildcard expansion cache can be cleared by hitting the Reload Files button.

Reference Primitive

Controls which prim to import from the multi-input connections.

Reference Automatically Chosen Primitive

If the referenced input connection has a default primitive set, use that. If there is no default prim, use the first Xform prim at the root. If there is no Xform prim at the root, use the first root prim of any type.

Reference Default Primitive

If the referenced input connection has a default primitive set, use that. If not, display a warning on this node.

Reference Specific Primitive

Reference in the scene graph path in the Reference Primitive Path parameter. In this mode the reference primitive specified in each row of the input table takes precedence over the value in the Reference Primitive Path parameter.

Reference Primitive Path

The scene graph path of the prim in the referenced layer that that is composed onto the stage. Contents of the referenced layer outside of this referenced primitive path will not appear on the composed stage. This parameter is only used if the Reference Primitive parameter is set to Reference Specific Primitive.

(If you set this field automaticPrim or defaultPrim, it mimics the behavior of setting Reference Primitive to Reference Automatically Chosen Primitive or Reference Default Primitive.)

Time Offset (in Frames)

Offsets all time samples from the file or target primitive on the first input. You can use this to re-time animations in the references file.

Time Scale

Scales all time samples from the file or target primitive on the first input. You can use this to re-time animations in the references file.

Reload Files

Click to reload the contents of all files imported by this node. This also clears the cache of file wildcard pattern expansions.

Created Primitives

Primitive Kind

If the prim at Primitive Path doesn’t exist, this node will create it. If it has to create the prim, it will set it to have this kind.

Setting this parameter to Auto will not author a Kind on the leaf primitive where the reference is added. Instead, it will examine the Kind of the prim after setting the reference, and automatically set the Kind of ancestor prims to ensure the leaf primitive is part of a valid model hierarchy. Note that this may result in adding a Kind to ancestor prims that were not created by this node. If the referenced prim has no kind, or is not a model kind, Auto mode will not author Kind on any prim.

Parent Primitive Type

If the prim at Primitive Path doesn’t exist, this node will create it. If it has to create the prim, it will give any intermediate prims it has to create this type.

Composition

Handle Missing Files

If the reference is to an external file, this controls what the node does if the referenced file does not exist.

Error for Missing Files

The node errors, preventing cooking the rest of the network.

Warn for Missing Files

The node shows a warning, then passes through the first input unchanged.

Ignore Missing Files

The node silently ignores the missing file, and passes through the first input unchanged.

Allow Missing Files on the Stage

Author the reference to the sublayer even if it currently doesn’t exist. This node and the following nodes will probably print warnings from the USD libraries about missing files.

Pre-Operation

If you set this to a value other than No Pre-Operation, the node clears existing references on the node.

No Pre-Operation

Do not clear existing references on the prim at Primitive Path.

Clear Reference Edits in Active Layer

Clear any additions or removals to the list of references on this prim made in the currently active layer.

This is not a non-destructive USD edit. It’s more like undoing any changes from previous nodes that are currently “pending” in the active layer.

Clear All References

Authors an override of the specified reference type which masks all existing references on this primitive, regardless of the layer in which they were authored. This provides a blank slate so that only the references specified by this node will remain.

Reference Operation

How new references added by this node interact with existing references on the prim at Primitive Path.

When editing references on a primitive, you are really making edits to a list. These edits are expressed as adding to the beginning or the end of the list created by composing all weaker layers, or by explicitly removing certain items from the list.

Add as Strongest References in Prepend List

Make new references stronger than any references from lower layers, and stronger than any previous “prepend” edits in the currently active layer.

Add as Weakest References in Prepend List

Make new references stronger than any references from lower layers, but weaker than any previous “prepend” edits in the currently active layer.

Add as Strongest References in Append List

Make new references weaker than any references from lower layers, but stronger than any previous “append” edits in the currently active layer.

Add as Weakest References in Append List

Make new references weaker than any references from lower layers, and weaker than any previous edits in the currently active layer.

Remove References

The layers or primitives referenced by this node are removed from the list of references on the destination primitive rather that being added.

Because this removal is expressed as a list edit, you can selectively remove specific layers from the list of references, no matter what layer authored the original reference.

LOP nodes

  • Add Variant

    Adds one or more variants to a variant set on a primitive. This node creates the primitive if it doesn’t exist.

  • Additional Render Vars

    Create multiple render vars.

  • Asset Reference

    Reference, Transform, and select variants of a USD Asset.

  • Assign Material

    Assigns a material to one or more USD primitives. You can use also programmatically assign materials using VEX, programmatically override material settings for each assignment, and programmatically assign materials to geometry subsets.

  • Assign Prototypes

    Switch point instances or USD instanceable prims to instance a different prototype.

  • Attribute VOP

    Create/edit USD attribute values using a VOP network.

  • Attribute Wrangle

    Create/edit USD primitive attributes using a VEX snippet.

  • Auto Select LOD

    Automatically selects a level-of-detail variant based on the primitive’s distance from the camera.

  • Bake Skinning

    Bakes animation driven by a UsdSkel into transforms and point positions.

  • Basis Curves

    Creates or edits a basis curves shape primitive.

  • Begin Context Options Block

    This node begins a block of LOP nodes, within which certain context options have certain values.

  • Blend

    Partially applies edits to a layer’s attributes based on a fractional weight.

  • Blend Constraint

    Blends transforms according to a list of weights specified as parameters.

  • Cache

    Caches the results of cooking the network at different times, increasing playback speed.

  • Camera

    Adds a USD camera to the scene.

  • Capsule

    Creates or edits a capsule (tube with hemispherical ends) shape primitive.

  • Collection

    Creates/edits collections using primitive patterns.

  • Component Geometry

    Geometry container or import source, in a network created by the Component Builder tool.

  • Component Geometry Variants

    Sets up geometry variants, in a network created by the Component Builder tool.

  • Component Material

    Assigns materials to geometry in a network created by the Component Builder tool.

  • Component Output

    Assembles the final Component prim, in a network created by the Component Builder tool.

  • Cone

    Creates or edits a cone shape primitive.

  • Configure Layer

    Edits metadata on a layer.

  • Configure Primitives

    Edits various metadata on one or more primitives.

  • Configure Properties

    Configures metadata on properties (relationships and attributes).

  • Configure Stage

    Configures metadata for how to load layers into the stage and asset resolution.

  • Coordinate System

    Define named coordinate systems used in shaders.

  • Copy Property

    Copy properties from one primitive to another, or renames properties on a primitive.

  • Create LOD

    Uses the PolyReduce SOP to automatically generate multiple levels of detail from a high-res model, and stores them as USD variants.

  • Cube

    Creates or edits a cube shape primitive.

  • Cylinder

    Creates or edits a cylinder shape primitive.

  • Distant Light

    Creates or edits a USD Distant Light, representing a far-off light source such as the sun. Adds some useful Karma-specific attributes.

  • Dome Light

    Creates or edits a USD Dome Light prim. A dome light emits light inward, simulating light coming from the sky/environment surrounding the scene.

  • Draw Mode

    Sets draw mode properties on USD model assets.

  • Drop

    Runs a simulation to drop primitives under gravity.

  • Duplicate

    Creates copies of a prim (and its descendants).

  • Edit

    Interactively transforms prims in the viewer. Can use physics collisions to position props realistically.

  • Edit Context Options

  • Edit Material Network

    Allows you to edit an existing USD material by modifying parameters and shader connections. This can be useful if the existing material is on a non-editable layer.

  • Edit Material Properties

    Lets you build a spare parameter interface that reflects material or shader input attributes to directly edit their values.

  • Edit Properties

    Lets you build a spare parameter interface to directly edit attribute and relationship values.

  • Edit Properties From Node

    Lets you refer to the parameter on another node to directly edit attribute and relationship values.

  • Edit Prototypes

    Modify the prototypes of native or point instances in-place, without disturbing the instancing setup.

  • Edit Target Layer

    Allows you to apply edits directly in a lower layer, instead of overriding prims and attributes in the active layer.

  • Error

    Generates a message, warning, or error, which can show up on a parent asset.

  • Explore Variants

    Visualize, set, or extract variants on primitives.

  • Extract Instances

    Converts (heroes) an instance into a real editable prim.

  • Fetch

    Grabs the output of another LOP, potentially in another LOP network.

  • File Cache

    Caches (writes out once and then reads from) USD layers (possibly animated) to disk.

  • Follow Path Constraint

    Constrains a prim to follow a path curve.

  • For Each

    The end node of a For-Each loop block.

  • Geometry Clip Sequence

  • Geometry Color

    Adds display color and display opacity primvars to geometry.

  • Geometry Light

    Adds properties to turn geometry into lights.

  • Geometry Sequence

    Imports a sequence of geometry files into LOPs as animated geometry.

  • Geometry Subset VOP

    Creates USD geometry subsets within geometry prims (similar to groups in SOPs) based on evaluating a VEXpression or VOP network.

  • Graft Branches

    Takes prims/branches from the second input and attaches them onto branches of the scene graph tree in the first input.

  • Graft Stages

    Takes scene graph trees from other inputs and attaches them onto branches of the scene graph tree in the first input.

  • HDA Dynamic Payload

    Cooks a OBJ or SOP asset on disk and imports the animated geometry output as a USD payload.

  • Hermite Curves

    Creates or edits a hermite curves shape primitive.

  • Houdini Preview Procedurals

    Invokes Houdini Procedurals while working interactively.

  • Houdini Procedural: Crowd

    Houdini Crowd Procedural for Solaris.

  • Houdini Procedural: Feather

    Generates feathers for rendering.

  • Houdini Procedural: Hair

    Houdini Procedural: Haie for Solaris.

  • Houdini Procedural: Ocean

    Houdini Ocean Procedural for Solaris.

  • Houdini Procedural: RBD

    Houdini Procedural: RBD for Solaris.

  • Husk Image Metadata

    Add Husk Custom Metadata to Render Products and Render Vars.

  • Inline USD

    Parses usda code representing a layer and adds it to the layer stack.

  • Insertion Point

    Represents a point in the node graph where nodes can be inserted.

  • Instancer

    Instances or copies primitives onto points.

  • Isolate Scene

    Work in masked areas of the stage.

  • Karma Background Plate

    Sets up AOVs and hold-out or matte objects that leave holes in the scene through which the background is visible. These prims still take shadows and contribute to reflections as if they were the background.

  • Karma Cryptomatte

    Setup Cryptomatte AOVs for Karma.

  • Karma Fog Box

    Creates a constant volume within a box.

  • Karma Physical Sky

    Creates a Karma Sky Dome and Sun Light rig.

  • Karma Render Products

    Create multiple render products sharing common settings.

  • Karma Render Settings

    Configure Render Settings for Karma.

  • Karma Shadow Catcher

    Configure render-time hold-out or matte objects.

  • Karma Sky Atmosphere

    Creates or edits a Karma Sky Atmosphere.

  • Karma Sky Dome Light

    Creates or edits a Karma Sky Dome Light.

  • Karma Standard Render Vars

    Create standard karma render vars (AOVs/Image Planes).

  • Karma Texture Baker

    Create a Render Settings primitive to create texture maps that define shading states for an object.

  • LPE Tag

    Manage Lights' LPE Tags.

  • Labs Biome Plant Scatter Import (Beta)

    Import a biome plant scatter from SOPs to LOPs.

  • Labs Karma AOVs for RenderMan Denoiser

    Generates AOVs for the Pixar RenderMan denoiser.

  • Labs ML CV Directory Variant

    Creates a variant set from USD assets in a directory.

  • Labs ML CV Dome Camera

    Generates a camera from one of the random positions within a specified 3D camera dome and frames the focus object within the camera’s view.

  • Labs ML CV Synthetics Karma Rop

    Renders RGB image or ID EXR file for segmentation masking.

  • Layer Break

    Starts a new active sublayer that subsequent nodes will edit, and indicates all previous layers will be discarded when saving to disk.

  • Layer Replace

    Replaces all uses of a certain layer with a substitute layer from its second input.

  • Layout

    Provides tools for populating a scene with instanced USD assets. You can place individual components, paint/scatter components in different ways using customizable brushes, and edit existing instances.

  • Light

    Creates or edits a USD Light prim. This node also adds some useful Karma-specific attributes.

  • Light Filter Library

    Authors USD light filter primitives from VOP nodes.

  • Light Linker

    Creates USD light link properties based on rules.

  • Light Mixer

    Lets you interactively edit USD properties for multiple lights.

  • Live Render

    Launches renders which react to upstream LOP changes and send the image to the Render Gallery.

  • Load Layer for Editing

  • Loft Payload Info

    Adds basic information from inside a payload to the primitive that loads the payload.

  • Look At Constraint

    Constrains a prim to always point toward a target.

  • Mask from Bounds

    Sets a primvar based on whether/by how much selected prims are inside a bounding shape.

  • Match Size

    Resizes and recenters the input geometry to match a reference bounding box.

  • Material Library

    Authors USD material primitives from shader VOP nodes.

  • Material Linker

    Creates material assignments based on rules.

  • Material Variation

    Creates attributes/primvars to override material parameters per-prim/instance.

  • Merge

    Merges the layers from incoming stages into a unified layer stack.

  • Merge Point Instancers

    Merges point instancers into a single consolidated point instancer.

  • Mesh

    Creates or edits a mesh shape primitive.

  • Modify Paths

    Modify asset path attribute values.

  • Modify Point Instances

    Modifies point transforms and property values for individual point instances.

  • Motion Blur

    Adds time samples to allow motion blur when rendering.

  • Null

    This node does nothing. It can be useful to insert a Null into a network as a fixed point in the network that you can refer to by name in expressions/scripts.

  • Output

    Represents the output of a subnetwork. Allows you to design a node asset with multiple outputs.

  • Parent Constraint

    Makes a primitive appear to inherit the transform hierarchy of another prim somewhere else in the tree.

  • Points

    Creates or edits a Points shape primitive.

  • Points Constraint

    Position and Orient primitives using point positions from a geometry.

  • Portal Light

    Creates or edits a USD Portal Light prim. A portal light is used in conjunction with a Dome Light to restrict the parts of the dome light that are sampled to illuminate a scene.

  • Primitive

    Bulk-creates one or more attributes of a certain type.

  • Prune

    Hides or deactivates primitives and point instances.

  • Python Script

    Lets you write Python code in the node to use the USD API to directly manipulate the stage.

  • RBD Destruction

    An example for a fracturing simulation in USD, also useful as a canned effect.

  • Reference

    References the contents of a external USD files and/or layers created by other LOP nodes into a branch of the existing scene graph tree. Can also remove or replace existing references.

  • Render Geometry Settings

    Applies renderer-specific geometry settings to geometry in the scene graph.

  • Render Pass

    Creates or edits a UsdRenderPass prim, which represents a render pass, with attributes configuring the content of the pass, and how to configure the renderer to generate the pass.

  • Render Product

    Creates or edits a UsdRenderProduct prim, which represents an output of a renderer (such as a rendered image file or other file-like artifact produced by a renderer), with attributes configuring how to generate the product.

  • Render Settings

    Creates or edits a UsdRenderSettings prim, which holds the general settings for rendering the scene.

  • Render Var

    Specifies a custom variable computed by the renderer and/or shaders, either a shader output or a light path expression (LPE).

  • Resample Transforms

    Generates interpolated transform time samples from existing time samples on USD prims.

  • Restructure Scene Graph

    This node has various operations for editing prim paths, variant sets, and composition arcs.

  • Retime Instances

    Offsets and/or scales the timing of animation on selected instances.

  • SOP Character Import

    Imports a character or animation from a SOP network into the USD scene graph.

  • SOP Create

    Lets you create geometry in a SOP subnetwork inside this node, so you can create geometry in-place in the LOP network instead of needing a separate SOP network.

  • SOP Crowd Import

    Imports a crowd from a SOP network into the USD scene graph.

  • SOP Import

    Imports geometry from a SOP network into the USD scene graph.

  • SOP Modify

    Converts USD geometry into SOP geometry, runs the SOP subnet inside this node on the geometry, and converts the changes back to USD overrides.

  • Scene Doctor

    Validates primitives on a USD stage.

  • Scene Import

    Imports models, materials, and lights from the Object level into the LOP network.

  • Scope

    Creates a scope primitive. Scope is the simplest form of grouping, and does not have a transform. Scopes can be useful for organizing the scene tree.

  • Set Extents

    Sets the bounding box metadata of selected primitives.

  • Set Variant

    Selects (switches to) one of the variants stored in a variant set on a primitive.

  • Shot Layer Edit

    Part of the Shot Builder Toolset, targets a specific layer for all shots that match the give pattern.

  • Shot Load

    Part of the Shot Builder Toolset, load USD data for your project.

  • Shot Output

    Part of the Shot Builder Toolset, outputs USD data and /or rendered images to your project.

  • Shot Split

    Passes through the input node’s stage, but may alter the shot context option depending on which output branch is being cooked.

  • Shot Switch

    Passes through one of several inputs, based on the shot context option.

  • Simulation Proxy

    Generates low-poly collison geometry suitable for physical simulation and creates a proxy relationship to the original model.

  • Sphere

    Creates or edits a sphere shape primitive.

  • Split Point Instancers

    Splits a point instancer into two or more instances, which divide up the original instances.

  • Split Primitive

    Splits USD geometry prims into child primitives based on geometry subsets or primvar values.

  • Split Scene

    This node splits a scene graph into two disjoint sets of primitives.

  • Stage Manager

    Provides a convenient interface to reference in many files at once and place them in the scene graph tree.

  • Store Parameter Values

    Lets you store temporary (unsaved) data in the stage.

  • Sublayer

    Imports from USD files or other LOP node chains into as sublayers, or removes/replaces/reorders existing sublayers.

  • Subnet

    Encapsulates a LOP subnetwork, allowing you to organize and hide parts of the network.

  • Surface Constraint

    Constrain a prim to stick to a surface.

  • Switch

    Passes through one of several inputs, based on a parameter choice or expression.

  • TimeShift

    Outputs the stage as it is at a different point in the timeline.

  • Transform

    Edits the transforms of selected USD primitives.

  • Transform UV

    Moves, rotates, and scales texture coordinates on USD primitives.

  • Transform by SOP Points

    Transforms USD primitives by SOP points with transform attributes.

  • USD ROP

  • USD Render ROP

  • Unassign Material

    Unbinds a material from one or more USD primitives.

  • Value Clip

  • Vary Material Assignment

    Assign different materials across a number of prims to create variation.

  • Volume

    References volume data on disk into a volume prim containing field prims.

  • Xform

    Creates or edits an Xform prim. Xform (and its sub-classes) represents a transform in the scene tree.