Houdini 19.5 Nodes LOP nodes

Retime Instances

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

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Since 18.0


This node offsets and/or scales the timing of animation on certain instances. Since USD doesn’t allow destructive editing, it does this by creating new retimed references of the instances' prototypes, and overriding the instances to refer to the new prototypes.

This node allows you to specify per-instance time offsets and scales in a number of ways:

  • You can get per-instance offsets and/or scales from float/int primvars. Optionally you can specify an explicit frame the instance should be referring to.

  • You can set a fixed number of random time offsets and/or scales constrained within a specified min and max time offset and/or scale.

  • You can create a SOP network inside this node (or elsewhere in the Houdini node hierarchy) that generates a point cloud where each point corresponds to an instance and float SOP attributes on the points specify time offsets and scales. Optionally you can specify an explicit frame the instances should be referring to. See point cloud editing below.


You can offset/scale the animation on regular prims with the Time Shift LOP. If you use Time Shift on an instancer, it will affect all instances equally, whereas this node lets you retime instances individually.

Point cloud editing

This node lets you build a SOP network to specify offsets and scales by processing points geometry that represents the instances.

  • If you choose “Internal SOP”, the node uses the nodes you build in the SOP subnet inside this node.

    • In this mode, the points are created for you and fed through the network (connect the output of Sub-Network Input #1 to the first node in your processing network).

  • If you choose “External SOP”, you can specify a SOP network anywhere in the Houdini node hierarchy. However, the network must generate the points with the proper attributes somehow.

    • The points must have a path SOP attribute set to the scene graph path of the instancer.

    • By default, the node will try to match points up with instances by matching point numbers to instance indices. This will probably only work if you are processing every instance in a single instancer. Otherwise, you should turn on Match by ID and set the id SOP attribute on each point to the index of the corresponding instance.

  • The points should have frameoffset and/or timescale float SOP attributes on the points to specify the offset and scale to apply to the corresponding instance, or a frame float SOP attribute when using the Explicit Frame option.

Tips and notes

  • This node works best for offsetting/scaling the animation on large groups of instances, or all instances that share a certain prototype. Since each separate timing requires a separate prototype, if you try to give each instance a different offset/scale, you will essentially “de-instance” the point instances (by having the same number of instances and prototypes).

  • If you are retiming prototypes created dynamically on an in-memory layer, you need to have a Cache LOP upstream from this node, so all frames are cooked and available.

    If the instances come from an external USD file, you don’t need a Cache, since the file should contain all the needed time samples.

  • By default, retiming prototypes will not affect the instance transforms or primvars (unless they are defined on the prototype prims themselves).

    You can choose to retime transforms and primvars defined at the instance level with the Retime transforms and Retime primvars parameters.

  • This node is optimized to only create new retimed prototypes for each unique combination of frame offset and time scale. Frame offsets equal to zero with a time scale of 1 can be ignored. However, this node still usually has to do a lot of work, and can be slow.



Whether you want to retime point instances, or instanceable primitives.


A space-separated list of instances, using /path[instance_index] syntax (for example, /geometry/instancer[0] /geometry/instancer[1]). To select all instances in an instancer, use /path[*]. To select a range, use /geometry/instancer[4-7] (the range is inclusive). To select instances inside nested instancers, use multiple indexes, for example /geometry/instancer[2][7].


When Type is “Native Instances”, a list of paths to instanceable prims.

Retime Using

How to compute the transform for each selected instance.

Internal SOP

Uses the SOP subnet inside this node to process points representing the instances.

External SOP

Uses an external SOP network that must generate points representing the instances from scratch. (See point cloud editing above.)

Primitive Properties

Gets the offset/scale primvars on the instancer/instance primitives themselves.

Random Values

Creates a set number of random offsets and scales distributed across instances.

Retime Method

When Retime Using is set to Internal SOP, External SOP or Primitive Properties, you can specify the retiming method.

Frame Offset and Time Scale

Retime using a frame offset and a time scale. The referenced prototype/primvar/transform will be looked up using ($F + frame offset) / time scale. This is the preferred method as it can be expressed as a constant, non time-dependent, value which can improve performance when retiming prototypes.

Explicit Frame

Set the time offset by specifying the frame at which the retimed prototype/primvar/transform should be referenced.


Since this will be a time dependent attribute or primvar in most cases, it will force the retimed prototype creation to be time dependent which will impact performance. When retiming prototypes by a fixed frame offset, it is generally recommended to use the Frame Offset and Time Scale retime method.

Match By ID

When Modify Using is “External SOP” and this is on, the node looks for id SOP attributes on the generated points. The id should be the index of the corresponding instance. (When this is off, the node matches point numbers to instance indices, which only works if you process every instance in a single instancer.)

SOP Path

When Modify Using is “External SOP”, the node path to the geometry node to cook to get the generated points. Each point in the output should correspond to one of the selected instances.


When Modify Using is “External SOP”, if this is not blank, only consider points in this point group.

Retime Prototypes

Create retimed prototypes for the specified instances. When instance animation is driven by instance-level transforms, turning this off will greatly improve performance.

Retime Transforms

Even if instance transforms are animated, by default this node does not affect them. Turn this on to re-time transform animation as well.

Retime Primvars

Even if instance-level primvars are animated, by default this node does not affect them. Turn this on to re-time primvar animation as well.

Evaluation Frame

In order to improve performance and to guarantee a fixed number of retimed prototypes, select a frame where the instances are retimed by a unique amount. Creating the retimed prototypes is split into its own non time-dependent process where possible which can have a significant impact on playback performance.

Only Affect Retimed

When this options is enabled, retimed prototypes with frame offsets equal to zero and time scales equal to 1, or explicit frames equal to the current frame, will be ignored.

Use Frame Offset

Enable frame offsets to drive the instance retiming. This timeshifts the instance animation.

Use Time Scale

Enable time scales to drive the instance retiming. This slows down or speeds up the instance animation.


When Retime Using is “Internal SOP” or “External SOP”, the name of the SOP point attribute that should specify the frame offset or time scale for each instance. When Use Explicit Frame is enabled, the name of the SOP point attribute that should specify the frame the retimed prototype should be using.


When Retime Using is “Primitive properties”, the name of a primvar on the instancer that should specify the frame offset or time scale for each instance. When Use Explicit Frame is enabled, the name of the SOP point attribute that should specify the frame the retimed prototype should be using.


When Retime Using is “Random Values”, specify the total number of unique frame offset or time scale values.


When Retime Using is “Random Values”, specify the minimum and maximum values for the frame offset or time scales.


When Retime Using is “Random Values”, specify the seed to use when generating a random number for each instance.


When Retime Using is “Random Values”, allows the user to control the distribution of the random values between the specified Min/Max.

Global Frame Offset

Apply this offset to all instances equally, in addition to any per-instance offsets.

Global Time Scale

Apply this time scaling factor to all instances equally, on top of any per-instance scales.

See also

LOP nodes

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  • 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.

  • Background Plate

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  • 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.

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

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    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.

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

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    Creates or edits a cube shape primitive.

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

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  • 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

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    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

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  • Edit Properties

    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

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  • 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 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.

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

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

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

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  • Houdini Procedural: Hair

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    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.

  • Instancer

    Create multiple render products sharing common settings.

  • Isolate Scene

    Work in masked areas of the stage.

  • Karma

    Renders the USD scene using Houdini’s Karma renderer.

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

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  • Light Linker

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  • Light Mixer

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  • Loft Payload Info

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  • Look At Constraint

    Constrains a prim to always point toward a target.

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  • Match Size

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  • Material Library

    Authors USD material primitives from shader VOP nodes.

  • Material Linker

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  • Material Variation

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

  • Merge LOP

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

  • 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

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    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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  • Retime Instances

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

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

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    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 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.

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    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.

  • 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.

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    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.


  • 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.