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UsdCollectionAPI Class Reference

#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
 
UsdSchemaType GetSchemaType () const
 
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 UsdPrimDefinitionGetSchemaClassPrimDefinition () const
 

Static Public Member Functions

static USD_API const
TfTokenVector
GetSchemaAttributeNames (bool includeInherited=true, const TfToken instanceName=TfToken())
 
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 UsdCollectionAPI ApplyCollection (const UsdPrim &prim, const TfToken &name, const TfToken &expansionRule=UsdTokens->expandPrims)
 
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 Public Member Functions inherited from UsdAPISchemaBase
static USD_API const
TfTokenVector
GetSchemaAttributeNames (bool includeInherited=true)
 
- Static Public Member Functions inherited from UsdSchemaBase
static const TfTokenVectorGetSchemaAttributeNames (bool includeInherited=true)
 

Static Public Attributes

static const UsdSchemaType schemaType = UsdSchemaType::MultipleApplyAPI
 
- Static Public Attributes inherited from UsdAPISchemaBase
static const UsdSchemaType schemaType = UsdSchemaType::AbstractBase
 
- Static Public Attributes inherited from UsdSchemaBase
static const UsdSchemaType schemaType = UsdSchemaType::AbstractBase
 

Protected Member Functions

USD_API UsdSchemaType _GetSchemaType () 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
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
 

Additional Inherited Members

- Static Protected Member Functions inherited from UsdAPISchemaBase
template<typename APISchemaType >
static APISchemaType _ApplyAPISchema (const UsdPrim &prim, const TfToken &apiSchemaName)
 
template<typename APISchemaType >
static APISchemaType _MultipleApplyAPISchema (const UsdPrim &prim, const TfToken &apiSchemaName, const TfToken &instanceName)
 

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

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 UsdSchemaType UsdCollectionAPI::_GetSchemaType ( ) const
overrideprotectedvirtual

Returns the type of schema this class belongs to.

See Also
UsdSchemaType

Reimplemented from UsdAPISchemaBase.

static USD_API UsdCollectionAPI UsdCollectionAPI::ApplyCollection ( const UsdPrim prim,
const TfToken name,
const TfToken expansionRule = UsdTokens->expandPrims 
)
static

Adds a new collection named name on the given prim, prim with the specified expansion-rule, expansionRule.

If a collection named name already exists, its expansion-rule is updated with the provided value and it is returned.

The name of a collection, name may itself be namespaced, to facilitate organization of collections into groups. However, the base-name of a collection (i.e. the last component of the collection name) should not be the same as one of the core collection schema properties, i.e. should not be 'expansionRule' or 'includes' or 'excludes'.

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 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:

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 198 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,
const TfToken  instanceName = TfToken() 
)
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

Friends And Related Function Documentation

friend class UsdSchemaRegistry
friend

Definition at line 270 of file collectionAPI.h.

Member Data Documentation

const UsdSchemaType UsdCollectionAPI::schemaType = UsdSchemaType::MultipleApplyAPI
static

Compile time constant representing what kind of schema this class is.

See Also
UsdSchemaType

Definition at line 158 of file collectionAPI.h.


The documentation for this class was generated from the following file: