Houdini 18.0 Nodes LOP nodes

Configure Properties

Configures metadata on properties (relationships and attributes).

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Overview

This node modifies attribute metadata (extra settings that can affect how the attribute is interpreted). To set an attribute’s value, use Edit Properties, Attribute Wrangle /nodes/lop/attributewrangle, or other LOP nodes that author attributes interactively (such as Edit) or at a higher level.

The metadata on properties is a "grab bag" of useful settings, such as:

  • Animation settings.

  • Color space.

  • Array size.

  • Space where studios or tools can store their own arbitrary per-property data.

Tips

  • This node will only author a bit of metadata if the corresponding parameter has its checkbox turned on. If the checkbox for a parameter is off, the node will not change any existing metadata corresponding to that parameter.

  • Metadata on attributes cannot meaningfully be animated.

The Configure Properties node provides the ability to set metadata on USD properties (attributes and relationships). Property metadata changes the way that the USD system interprets the attribute values. This node can also be used to add custom data to properties. Custom data is a set of named values that can be attached to a property, primitive, or layer. These custom data values are ignored by USD, but may be useful for transmitting studio-specific data from one application to another.

This node does node provide a way to set attribute values. For that, use the E

Parameters

Primitives

The primitive(s) the node should operate on. You can drag primitives from the scene graph tree pane into this textbox to add their paths, or click the Reselect button beside the text box to select the primitives in the viewer, or ⌃ Ctrl-click the Reselect button to choose prims from a pop-up tree window. You can also use primitive patterns for advanced matching, including matching all prims in a collection (using /path/to/prim.collection:name).

Properties

A space separated list of property names which should be affected by this node. Normal Houdini string matching rules apply (accepting wildcards and using ^ to exclude patterns). The node compares this pattern against every property name on every selected primitive. This can mean the node affects a different set of properties on each primitive.

Variability

This is a hint to the USD system indicating whether the property can vary over time, or should be uniform over all time.

Color Space

For attributes with a color data type, this metadata affects how USD interprets the color value. See the USD documentation for further information on how USD uses this color space metadata.

Interpolation

For primvar attributes, the Interpolation metadata controls how the primvar is applied to the geometry. Options are: Constant (Detail)

The attribute should be an array with a single value which is applied to the entire geometry. Equivalent to Houdini Detail attributes in SOPs.

Uniform (Primitive)

The attribute should be an array with a separate value for each polygon in a Mesh primitive, or curve in a BasisCurves primitive (same length as the faceVertexCounts or curveVertexCounts attributes). Equivalent to Houdini Primitive attributes in SOPs.

Vertex (Point)

The attribute should be an array with a separate value for each point in the primitive (same length as the points attribute). Equivalent to Houdini Point attributes in SOPs.

Varying (Vertex)

The attribute should be an array with a separate value for each point used by each polygon (same length as the faceVertexIndices attribute). This is equivalent to Vertex interpolation on BasisCurves primitives. Equivalent to Houdini Vertex attributes in SOPs.

Face Varying (Vertex)

The attribute should be an array with a separate value for each point used by each polygon (same length as the faceVertexIndices attribute). This is equivalent to Vertex interpolation on BasisCurves primitives. Equivalent to Houdini Vertex attributes in SOPs. This is the same as Varying interpolation except for how the interpolation is performed on the surface or curve between vertices. See the USD documentation for more information.

Element Size

For a primvar attribute, this metadata controls how many elements of the array belong to each component of the geometry. This is necessary because primvar values are always flat arrays. As an example, suppose a single square exists in a Mesh primitive. A primvar with Vertex interpolation should have four values (one for each corner). With an element size of 1, this primvar attribute should have exactly four elements of whatever data type is set on the attribute (strings, vectors, colours, etc). With an element size of 5, the primvar attribute value should be an array of 20 elements, of which 5 belong to each corner of the square.

Number of Custom Data

The metadata of every prim contains a dictionary for use by software packages and/or studios to store custom data. You can set or edit multiple custom key-value pairs here. Set the number of items to set/edit, or use the plus and minus buttons to add or remove items.

Custom Data Name

For each item of custom data, the name of the item.

Custom Data Type

For each item of custom data, the data type of the value. The only choices are string and number.

Custom Data Value

For each item of custom data, the value to associate with the name.

(Behind the scenes there are two different parameters (customdatastrvaluen and customdatafloatvaluen) both labeled Custom data value, with the visible one controlled by whether Custom data type is set to "string" or "number". This may be relevant if you are using expressions or scripting these values.)

See also

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.

  • 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.

  • 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.

  • 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.

  • 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 a collection using selected prims.

  • 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.

  • 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.

  • 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.

  • 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

    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 Properties

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

  • Edit Prototype

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

  • 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.

  • Extract Instances

    Converts an instance into a "real" editable prim.

  • Fetch

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

  • Follow Path Constraint

    Constrains a prim to follow a path curve.

  • For Each

    The end node of a For-Each loop block.

  • Geometry Subset VOP

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

  • Graft

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

  • Inline USD

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

  • Instancer

    Instances or copies primitives onto points.

  • Karma Procedural

    Sets up render-time instantiation for Karma.

  • Karma Render Properties

    Configure Render Properties for Karma (Beta).

  • Karma Standard Render Vars

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

  • LOP nodes

    LOP nodes generate USD describing characters, props, lighting, and rendering.

  • Layer Break

    Starts a new active sublayer that subsequent nodes will edit.

  • Layer Replace

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

  • Light

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

  • Light Linker

    Creates USD light link properties based on rules.

  • Light Mixer

    Lets you interactively edit USD properties for multiple lights.

  • Load Layer

  • Look At Constraint

    Constrains a prim to always point toward a target.

  • Material Library

    Imports Material VOP nodes as USD material prims.

  • Material Linker

    Creates material assignments based on rules.

  • 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.

  • Modify Point Instances

    Modify point transforms and property values for individual point instances.

  • 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 Constraint

    Position and Orient primitives using point positions from a geometry.

  • 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.

  • Reference

    References the contents of an external USD file into a branch of the existing scene graph tree, or removes/replaces existing references.

  • Render Geometry Settings

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

  • 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).

  • Retime Instances

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

  • 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 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.

  • 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.

  • 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.

  • 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 ROP

  • USD Render ROP

  • 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.

  • attribvop