#include <collectionAPI.h>

Inheritance diagram for UsdCollectionAPI:

Public Types
using	MembershipQuery = UsdCollectionMembershipQuery

Public Member Functions
	UsdCollectionAPI (const UsdPrim &prim=UsdPrim(), const TfToken &name=TfToken())

	UsdCollectionAPI (const UsdSchemaBase &schemaObj, const TfToken &name)

virtual USD_API	~UsdCollectionAPI ()
	Destructor. More...

TfToken	GetName () const
	Returns the name of this multiple-apply schema instance. More...

USD_API UsdAttribute	GetExpansionRuleAttr () const

USD_API UsdAttribute	CreateExpansionRuleAttr (VtValue const &defaultValue=VtValue(), bool writeSparsely=false) const

USD_API UsdAttribute	GetIncludeRootAttr () const

USD_API UsdAttribute	CreateIncludeRootAttr (VtValue const &defaultValue=VtValue(), bool writeSparsely=false) const

USD_API UsdRelationship	GetIncludesRel () const

USD_API UsdRelationship	CreateIncludesRel () const

USD_API UsdRelationship	GetExcludesRel () const

USD_API UsdRelationship	CreateExcludesRel () const

USD_API SdfPath	GetCollectionPath () const

USD_API UsdCollectionMembershipQuery	ComputeMembershipQuery () const

USD_API void	ComputeMembershipQuery (UsdCollectionMembershipQuery *query) const

USD_API bool	HasNoIncludedPaths () const

USD_API bool	Validate (std::string *reason) const

USD_API bool	ResetCollection () const

USD_API bool	BlockCollection () const

Collection Authoring API
Convenience API for adding or removing prims and properties to (or from) a collection..
USD_API bool	IncludePath (const SdfPath &pathToInclude) const

USD_API bool	ExcludePath (const SdfPath &pathToExclude) const

Public Member Functions inherited from UsdAPISchemaBase
	UsdAPISchemaBase (const UsdPrim &prim=UsdPrim())

	UsdAPISchemaBase (const UsdSchemaBase &schemaObj)

virtual USD_API	~UsdAPISchemaBase ()=0
	Destructor. More...

Public Member Functions inherited from UsdSchemaBase
bool	IsConcrete () const

bool	IsTyped () const

bool	IsAPISchema () const
	Returns whether this is an API schema or not. More...

bool	IsAppliedAPISchema () const

bool	IsMultipleApplyAPISchema () const

UsdSchemaKind	GetSchemaKind () const
	Returns the kind of schema this class is. More...

USD_API	UsdSchemaBase (const UsdPrim &prim=UsdPrim())
	Construct and store `prim` as the held prim. More...

USD_API	UsdSchemaBase (const UsdSchemaBase &otherSchema)
	Construct and store for the same prim held by `otherSchema`. More...

virtual USD_API	~UsdSchemaBase ()
	Destructor. More...

USD_API	operator bool () const

UsdPrim	GetPrim () const
	Return this schema object's held prim. More...

SdfPath	GetPath () const
	Shorthand for GetPrim()->GetPath(). More...

USD_API const UsdPrimDefinition *	GetSchemaClassPrimDefinition () const

Static Public Member Functions
static USD_API const TfTokenVector &	GetSchemaAttributeNames (bool includeInherited=true)

static USD_API TfTokenVector	GetSchemaAttributeNames (bool includeInherited, const TfToken &instanceName)

static USD_API UsdCollectionAPI	Get (const UsdStagePtr &stage, const SdfPath &path)

static USD_API UsdCollectionAPI	Get (const UsdPrim &prim, const TfToken &name)

static USD_API bool	IsSchemaPropertyBaseName (const TfToken &baseName)

static USD_API bool	IsCollectionAPIPath (const SdfPath &path, TfToken *name)

static USD_API bool	CanApply (const UsdPrim &prim, const TfToken &name, std::string *whyNot=nullptr)

static USD_API UsdCollectionAPI	Apply (const UsdPrim &prim, const TfToken &name)

static USD_API UsdCollectionAPI	GetCollection (const UsdStagePtr &stage, const SdfPath &collectionPath)

static USD_API UsdCollectionAPI	GetCollection (const UsdPrim &prim, const TfToken &name)

static USD_API std::vector < UsdCollectionAPI >	GetAllCollections (const UsdPrim &prim)
	Returns all the named collections on the given USD prim. More...

static USD_API SdfPath	GetNamedCollectionPath (const UsdPrim &prim, const TfToken &collectionName)

static USD_API std::set < UsdObject >	ComputeIncludedObjects (const UsdCollectionMembershipQuery &query, const UsdStageWeakPtr &stage, const Usd_PrimFlagsPredicate &pred=UsdPrimDefaultPredicate)

static USD_API SdfPathSet	ComputeIncludedPaths (const UsdCollectionMembershipQuery &query, const UsdStageWeakPtr &stage, const Usd_PrimFlagsPredicate &pred=UsdPrimDefaultPredicate)

static USD_API bool	CanContainPropertyName (const TfToken &name)

Static Public Member Functions inherited from UsdAPISchemaBase
static USD_API const TfTokenVector &	GetSchemaAttributeNames (bool includeInherited=true)

Static Public Member Functions inherited from UsdSchemaBase
static const TfTokenVector &	GetSchemaAttributeNames (bool includeInherited=true)

Static Public Attributes
static const UsdSchemaKind	schemaKind = UsdSchemaKind::MultipleApplyAPI

Static Public Attributes inherited from UsdAPISchemaBase
static const UsdSchemaKind	schemaKind = UsdSchemaKind::AbstractBase

Static Public Attributes inherited from UsdSchemaBase
static const UsdSchemaKind	schemaKind = UsdSchemaKind::AbstractBase

Protected Member Functions
USD_API UsdSchemaKind	_GetSchemaKind () const override

Protected Member Functions inherited from UsdAPISchemaBase
	UsdAPISchemaBase (const UsdPrim &prim, const TfToken &instanceName)

	UsdAPISchemaBase (const UsdSchemaBase &schemaObj, const TfToken &instanceName)

const TfToken &	_GetInstanceName () const

USD_API bool	_IsCompatible () const override

Protected Member Functions inherited from UsdSchemaBase
virtual UsdSchemaKind	_GetSchemaType () const

const TfType &	_GetType () const

USD_API UsdAttribute	_CreateAttr (TfToken const &attrName, SdfValueTypeName const &typeName, bool custom, SdfVariability variability, VtValue const &defaultValue, bool writeSparsely) const

Friends
class	UsdSchemaRegistry

Detailed Description

This is a general purpose API schema, used to describe a collection of heterogeneous objects within the scene. "Objects" here may be prims or properties belonging to prims or other collections. It's an add-on schema that can be applied many times to a prim with different collection names.

A collection allows an enumeration of a set of paths to include and a set of paths to exclude. Whether the descendants of an included path are members of a collection are decided by its expansion rule (see below). If the collection excludes paths that are not descendents of included paths, the collection implicitly includes the root path </>. If such a collection also includes paths that are not descendants of the excluded paths, it is considered invalid, since the intention is ambiguous.

All the properties authored by the schema are namespaced under "collection:". The given name of the collection provides additional namespacing for the various per-collection properties, which include the following:

uniform token collection:collectionName:expansionRule - specified how the paths that are included in the collection must be expanded to determine its members. Possible values include:
- explicitOnly - only paths in the includes rel targets and not in the excludes rel targets belong to the collection.
- expandPrims - all the prims at or below the includes rel- targets (and not under the excludes rel-targets) belong to the collection. Any property paths included in the collection would, of course, 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 whole lot of UsdObjects very concisely.
bool collection:collectionName:includeRoot - boolean attribute indicating whether the pseudo-root path </> should be counted as one of the included target paths. The fallback is false. This separate attribute is required because relationships cannot directly target the root.
rel collection:collectionName:includes - specifies a list of targets that are included in the collection. This can target prims or properties directly. A collection can insert the rules of another collection by making its includes relationship target the collection:{collectionName} property on the owning prim of the collection to be included. Such a property may not (and typically does not) exist on the UsdStage, but it is the path that is used to refer to the collection. It is important to note that including another collection does not guarantee the contents of that collection will be in the final collection; instead, the rules are merged. This means, for example, an exclude entry may exclude a portion of the included collection. When a collection includes one or more collections, the order in which targets are added to the includes relationship may become significant, if there are conflicting opinions about the same path. Targets that are added later are considered to be stronger than earlier targets for the same path.
rel collection:collectionName:excludes - specifies a list of targets that are excluded below the included paths in this collection. This can target prims or properties directly, but cannot target another collection. This is to keep the membership determining logic simple, efficient and easier to reason about. Finally, it is invalid for a collection to exclude paths that are not included in it. The presence of such "orphaned" excluded paths will not affect the set of paths included in the collection, but may affect the performance of querying membership of a path in the collection (see UsdCollectionAPI::MembershipQuery::IsPathIncluded) or of enumerating the objects belonging to the collection (see UsdCollectionAPI::GetIncludedObjects).

Implicit inclusion

In some scenarios it is useful to express a collection that includes everything except certain paths. To support this, a collection that has an exclude that is not a descendent of any include will include the root path </>.

Creating collections in C++

For any described attribute Fallback Value or Allowed Values below that are text/tokens, the actual token is published and defined in UsdTokens. So to set an attribute to the value "rightHanded", use UsdTokens->rightHanded as the value.

Definition at line 152 of file collectionAPI.h.

Member Typedef Documentation

using UsdCollectionAPI::MembershipQuery = UsdCollectionMembershipQuery

Definition at line 450 of file collectionAPI.h.

Constructor & Destructor Documentation

UsdCollectionAPI::UsdCollectionAPI	(	const UsdPrim &	prim = `UsdPrim()`,
		const TfToken &	name = `TfToken()`
	)

inlineexplicit

Construct a UsdCollectionAPI on UsdPrim prim with name name . Equivalent to UsdCollectionAPI::Get( prim.GetStage(), prim.GetPath().AppendProperty( "collection:name"));

for a valid prim, but will not immediately throw an error for an invalid prim

Definition at line 169 of file collectionAPI.h.

UsdCollectionAPI::UsdCollectionAPI	(	const UsdSchemaBase &	schemaObj,
		const TfToken &	name
	)

inlineexplicit

Construct a UsdCollectionAPI on the prim held by schemaObj with name name. Should be preferred over UsdCollectionAPI(schemaObj.GetPrim(), name), as it preserves SchemaBase state.

Definition at line 178 of file collectionAPI.h.

virtual USD_API UsdCollectionAPI::~UsdCollectionAPI ( )

virtual

Destructor.

Member Function Documentation

USD_API UsdSchemaKind UsdCollectionAPI::_GetSchemaKind ( ) const

overrideprotectedvirtual

Returns the kind of schema this class belongs to.

See Also: UsdSchemaKind

Reimplemented from UsdAPISchemaBase.

static USD_API UsdCollectionAPI UsdCollectionAPI::Apply	(	const UsdPrim &	prim,
		const TfToken &	name
	)

static

Applies this multiple-apply API schema to the given prim along with the given instance name, name.

This information is stored by adding "CollectionAPI:<i>name</i>" to the token-valued, listOp metadata apiSchemas on the prim. For example, if name is 'instance1', the token 'CollectionAPI:instance1' is added to 'apiSchemas'.

Returns: A valid UsdCollectionAPI object is returned upon success. An invalid (or empty) UsdCollectionAPI object is returned upon failure. See UsdPrim::ApplyAPI() for conditions resulting in failure.

See Also: UsdPrim::GetAppliedSchemas(); UsdPrim::HasAPI(); UsdPrim::CanApplyAPI(); UsdPrim::ApplyAPI(); UsdPrim::RemoveAPI()

USD_API bool UsdCollectionAPI::BlockCollection ( ) const

Blocks the targets of the includes and excludes relationships of the collection, making it <* empty if "includeRoot" is false (or unset) or

include everything if "includeRoot" is true. (assuming there are no opinions in stronger edit targets).

static USD_API bool UsdCollectionAPI::CanApply	(	const UsdPrim &	prim,
		const TfToken &	name,
		std::string *	whyNot = `nullptr`
	)

static

Returns true if this multiple-apply API schema can be applied, with the given instance name, name, to the given prim. If this schema can not be a applied the prim, this returns false and, if provided, populates whyNot with the reason it can not be applied.

Note that if CanApply returns false, that does not necessarily imply that calling Apply will fail. Callers are expected to call CanApply before calling Apply if they want to ensure that it is valid to apply a schema.

See Also: UsdPrim::GetAppliedSchemas(); UsdPrim::HasAPI(); UsdPrim::CanApplyAPI(); UsdPrim::ApplyAPI(); UsdPrim::RemoveAPI()

static USD_API bool UsdCollectionAPI::CanContainPropertyName ( const TfToken & name )

static

Test whether a given name contains the "collection:" prefix

static USD_API std::set<UsdObject> UsdCollectionAPI::ComputeIncludedObjects	(	const UsdCollectionMembershipQuery &	query,
		const UsdStageWeakPtr &	stage,
		const Usd_PrimFlagsPredicate &	pred = `UsdPrimDefaultPredicate`
	)

static

Returns all the usd objects that satisfy the predicate, pred in the collection represented by the UsdCollectionMembershipQuery object, query.

The results depends on the load state of the UsdStage, stage.

static USD_API SdfPathSet UsdCollectionAPI::ComputeIncludedPaths	(	const UsdCollectionMembershipQuery &	query,
		const UsdStageWeakPtr &	stage,
		const Usd_PrimFlagsPredicate &	pred = `UsdPrimDefaultPredicate`
	)

static

Returns all the paths that satisfy the predicate, pred in the collection represented by the UsdCollectionMembershipQuery object, query.

The result depends on the load state of the UsdStage, stage.

USD_API UsdCollectionMembershipQuery UsdCollectionAPI::ComputeMembershipQuery ( ) const

Computes and returns a UsdCollectionMembershipQuery object which can be used to query inclusion or exclusion of paths in the collection.

USD_API void UsdCollectionAPI::ComputeMembershipQuery ( UsdCollectionMembershipQuery * query ) const

Populates the UsdCollectionMembershipQuery object with data from this collection, so it can be used to query inclusion or exclusion of paths.

USD_API UsdRelationship UsdCollectionAPI::CreateExcludesRel ( ) const

See GetExcludesRel(), and also Usd_Create_Or_Get_Property for when to use Get vs Create

USD_API UsdAttribute UsdCollectionAPI::CreateExpansionRuleAttr	(	VtValue const &	defaultValue = `VtValue()`,
		bool	writeSparsely = `false`
	)		const

See GetExpansionRuleAttr(), and also Usd_Create_Or_Get_Property for when to use Get vs Create. If specified, author defaultValue as the attribute's default, sparsely (when it makes sense to do so) if writeSparsely is true - the default for writeSparsely is false.

USD_API UsdAttribute UsdCollectionAPI::CreateIncludeRootAttr	(	VtValue const &	defaultValue = `VtValue()`,
		bool	writeSparsely = `false`
	)		const

See GetIncludeRootAttr(), and also Usd_Create_Or_Get_Property for when to use Get vs Create. If specified, author defaultValue as the attribute's default, sparsely (when it makes sense to do so) if writeSparsely is true - the default for writeSparsely is false.

USD_API UsdRelationship UsdCollectionAPI::CreateIncludesRel ( ) const

See GetIncludesRel(), and also Usd_Create_Or_Get_Property for when to use Get vs Create

USD_API bool UsdCollectionAPI::ExcludePath ( const SdfPath & pathToExclude ) const

Excludes or removes the given path, pathToExclude from the collection.

If the collection is empty, the collection becomes one that includes all paths except the givne path. Otherwise, this does nothing if the path is not included in the collection.

This does not modify the expansion-rule of the collection. Hence, if the expansionRule is expandPrims or expandPrimsAndProperties, then the descendants of pathToExclude will also be excluded from the collection, unless explicitly included.

See Also: UsdCollectionAPI::IncludePath()

static USD_API UsdCollectionAPI UsdCollectionAPI::Get	(	const UsdStagePtr &	stage,
		const SdfPath &	path
	)

static

Return a UsdCollectionAPI holding the prim adhering to this schema at path on stage. If no prim exists at path on stage, or if the prim at that path does not adhere to this schema, return an invalid schema object. path must be of the format <path>.collection:name .

This is shorthand for the following:

TfToken name = SdfPath::StripNamespace(path.GetToken());
UsdCollectionAPI(
    stage->GetPrimAtPath(path.GetPrimPath()), name);

static USD_API UsdCollectionAPI UsdCollectionAPI::Get	(	const UsdPrim &	prim,
		const TfToken &	name
	)

static

Return a UsdCollectionAPI with name name holding the prim prim. Shorthand for UsdCollectionAPI(prim, name);

static USD_API std::vector<UsdCollectionAPI> UsdCollectionAPI::GetAllCollections ( const UsdPrim & prim )

static

Returns all the named collections on the given USD prim.

static USD_API UsdCollectionAPI UsdCollectionAPI::GetCollection	(	const UsdStagePtr &	stage,
		const SdfPath &	collectionPath
	)

static

Returns the collection represented by the given collection path, collectionPath on the given USD stage.

static USD_API UsdCollectionAPI UsdCollectionAPI::GetCollection	(	const UsdPrim &	prim,
		const TfToken &	name
	)

static

Returns the schema object representing a collection named name on the given prim.

USD_API SdfPath UsdCollectionAPI::GetCollectionPath ( ) const

Returns the canonical path that represents this collection. This points to a property named "collection:{collectionName}" on the prim defining the collection (which won't really exist as a property on the UsdStage, but will be used to refer to the collection). This is the path to be used to "include" this collection in another collection.

USD_API UsdRelationship UsdCollectionAPI::GetExcludesRel ( ) const

Specifies a list of targets that are excluded below the included paths in this collection. This can target prims or properties directly, but cannot target another collection. This is to keep the membership determining logic simple, efficient and easier to reason about. Finally, it is invalid for a collection to exclude paths that are not included in it. The presence of such "orphaned" excluded paths will not affect the set of paths included in the collection, but may affect the performance of querying membership of a path in the collection (see UsdCollectionAPI::MembershipQuery::IsPathIncluded) or of enumerating the objects belonging to the collection (see UsdCollectionAPI::GetIncludedObjects).

USD_API UsdAttribute UsdCollectionAPI::GetExpansionRuleAttr ( ) const

Specifies how the paths that are included in the collection must be expanded to determine its members.


Declaration	`uniform token expansionRule = "expandPrims"`
C++ Type	TfToken
Usd Type	SdfValueTypeNames->Token
Variability	SdfVariabilityUniform
Allowed Values	explicitOnly, expandPrims, expandPrimsAndProperties

USD_API UsdAttribute UsdCollectionAPI::GetIncludeRootAttr ( ) const

Boolean attribute indicating whether the pseudo-root path </> should be counted as one of the included target paths. The fallback is false. This separate attribute is required because relationships cannot directly target the root.


Declaration	`uniform bool includeRoot`
C++ Type	bool
Usd Type	SdfValueTypeNames->Bool
Variability	SdfVariabilityUniform

USD_API UsdRelationship UsdCollectionAPI::GetIncludesRel ( ) const

Specifies a list of targets that are included in the collection. This can target prims or properties directly. A collection can insert the rules of another collection by making its includes relationship target the collection:{collectionName} property on the owning prim of the collection to be included

TfToken UsdCollectionAPI::GetName ( ) const

inline

Returns the name of this multiple-apply schema instance.

Definition at line 204 of file collectionAPI.h.

static USD_API SdfPath UsdCollectionAPI::GetNamedCollectionPath	(	const UsdPrim &	prim,
		const TfToken &	collectionName
	)

static

Returns the canonical path to the collection named, name on the given prim, prim.

See Also: GetCollectionPath()

static USD_API const TfTokenVector& UsdCollectionAPI::GetSchemaAttributeNames ( bool includeInherited = true )

static

Return a vector of names of all pre-declared attributes for this schema class and all its ancestor classes. Does not include attributes that may be authored by custom/extended methods of the schemas involved.

static USD_API TfTokenVector UsdCollectionAPI::GetSchemaAttributeNames	(	bool	includeInherited,
		const TfToken &	instanceName
	)

static

Return a vector of names of all pre-declared attributes for this schema class and all its ancestor classes for a given instance name. Does not include attributes that may be authored by custom/extended methods of the schemas involved. The names returned will have the proper namespace prefix.

USD_API bool UsdCollectionAPI::HasNoIncludedPaths ( ) const

Returns true if the collection has nothing included in it. This requires both that the includes relationship have no target paths, and that the includeRoot attribute be false. Note that there may be cases where the collection has no objects included in it even when HasNoIncludedPaths() returns false. For example, if the included objects are unloaded or if the included objects are also excluded.

USD_API bool UsdCollectionAPI::IncludePath ( const SdfPath & pathToInclude ) const

Includes or adds the given path, pathToInclude in the collection.

This does nothing if the path is already included in the collection.

This does not modify the expansion-rule of the collection. Hence, if the expansionRule is expandPrims or expandPrimsAndProperties, then the descendants of pathToInclude will be also included in the collection unless explicitly excluded.

See Also: UsdCollectionAPI::ExcludePath()

static USD_API bool UsdCollectionAPI::IsCollectionAPIPath	(	const SdfPath &	path,
		TfToken *	name
	)

static

Checks if the given path path is of an API schema of type CollectionAPI. If so, it stores the instance name of the schema in name and returns true. Otherwise, it returns false.

static USD_API bool UsdCollectionAPI::IsSchemaPropertyBaseName ( const TfToken & baseName )

static

Checks if the given name baseName is the base name of a property of CollectionAPI.

USD_API bool UsdCollectionAPI::ResetCollection ( ) const

Resets the collection by clearing both the includes and excludes targets of the collection in the current UsdEditTarget.

Note: This does not modify the "includeRoot" attribute which is used to include or exclude everything (i.e. the pseudoRoot) in the USD stage.

USD_API bool UsdCollectionAPI::Validate ( std::string * reason ) const

Validates the collection by checking the following rules:

a collection's expansionRule should be one of "explicitOnly", "expandPrims" or "expandPrimsAndProperties".
a collection should not have have a circular dependency on another collection.
a collection should not have both includes and excludes among its top-level rules