UsdCollection

Pattern-Based Collections (PBC) was introduced in USD 23.11 and is now fully integrated in Katana, with the addition of the UsdCollection node. This allows you to define and modify USD collections.

The UsdCollection node has two modes that are found in the action parameter’s dropdown: create and edit.

action > create

This mode defines a USD collection.

• Add a location in the primPath parameter and give your collection a name in the collectionName parameter.

• Use membershipExpression, include and exclude widgets to add paths.

action > edit

This mode allows modifying incoming collections.

• Specify a location in the primPath parameter and select the collection within the collectionName parameter.

• Inputs will then be automatically pre-populated with the paths set within the collection, and can be further edited.

Note: For further information about PBC, see Pattern-Based Collections with USD.

Tip: You can see a list of the CEL and USD (PBC) Collections in your project in the Collections panel at the top of the Scene Explorer and via the Collection working set indicators . See Using the Scene Explorer.

Inputs

Connection Type	Connection Name	Function
input	in	The incoming scene graph data that the node will operate on or modify.

Controls

Control (UI)	Default Value	Function
action	create	The action of this node is to either create a new or edit an existing collection. If editing an existing collection, only one prim path can be set, otherwise when creating a collection, collections can be created at one or more prim paths.
primPaths	N/A	The prim paths on which to create the collection
collectionName	N/A	The name of the collection to create or edit.
expansionRule	expandPrims	Specifies how the paths that are included in the collection must be expanded to determine its members. explicitOnly - only paths in the includes section and not in the excludes section belong to the collection. expandPrims - all the prims at or below the relationship includes (and not under the relationship excludes) belong to the collection. Any property paths included in the collection would also be honored. This is the default behavior as it satisfies most use cases. expandPrimsAndProperties - like expandPrims, but also includes all properties on all matched prims. We're still not quite sure what the use cases are for this, but you can use it to capture a large number of UsdObjects very concisely.
includeRoot	disabled	Boolean attribute indicating whether the pseudo-root path should be counted as one of the included target paths. This separate attribute is required because relationships cannot directly target the root.