WARNING: Draft API, this design is not fixed and may change in the future. More...

Inherits UsdAPISchemaBase.

Public Member Functions
	PhysxSchemaPhysxTendonAttachmentRootAPI (const UsdPrim &prim=UsdPrim(), const TfToken &name=TfToken())
	Construct a PhysxSchemaPhysxTendonAttachmentRootAPI on UsdPrim `prim` with name `name` . More...

	PhysxSchemaPhysxTendonAttachmentRootAPI (const UsdSchemaBase &schemaObj, const TfToken &name)
	Construct a PhysxSchemaPhysxTendonAttachmentRootAPI on the prim held by `schemaObj` with name `name`. More...

virtual PHYSXSCHEMA_API	~PhysxSchemaPhysxTendonAttachmentRootAPI ()
	Destructor. More...

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

PHYSXSCHEMA_API UsdAttribute	GetTendonEnabledAttr () const
	Enables/disables the tendon from contributing to the articulation dynamics. More...

PHYSXSCHEMA_API UsdAttribute	CreateTendonEnabledAttr (VtValue const &defaultValue=VtValue(), bool writeSparsely=false) const
	See GetTendonEnabledAttr(), and also Usd_Create_Or_Get_Property for when to use Get vs Create. More...

PHYSXSCHEMA_API UsdAttribute	GetStiffnessAttr () const
	Common sub-tendon length spring stiffness. More...

PHYSXSCHEMA_API UsdAttribute	CreateStiffnessAttr (VtValue const &defaultValue=VtValue(), bool writeSparsely=false) const
	See GetStiffnessAttr(), and also Usd_Create_Or_Get_Property for when to use Get vs Create. More...

PHYSXSCHEMA_API UsdAttribute	GetDampingAttr () const
	Common sub-tendon length damping. More...

PHYSXSCHEMA_API UsdAttribute	CreateDampingAttr (VtValue const &defaultValue=VtValue(), bool writeSparsely=false) const
	See GetDampingAttr(), and also Usd_Create_Or_Get_Property for when to use Get vs Create. More...

PHYSXSCHEMA_API UsdAttribute	GetLimitStiffnessAttr () const
	Common sub-tendon length-limit spring stiffness. More...

PHYSXSCHEMA_API UsdAttribute	CreateLimitStiffnessAttr (VtValue const &defaultValue=VtValue(), bool writeSparsely=false) const
	See GetLimitStiffnessAttr(), and also Usd_Create_Or_Get_Property for when to use Get vs Create. More...

PHYSXSCHEMA_API UsdAttribute	GetOffsetAttr () const
	Common sub-tendon length offset. More...

PHYSXSCHEMA_API UsdAttribute	CreateOffsetAttr (VtValue const &defaultValue=VtValue(), bool writeSparsely=false) const
	See GetOffsetAttr(), and also Usd_Create_Or_Get_Property for when to use Get vs Create. More...

Static Public Member Functions
static PHYSXSCHEMA_API const TfTokenVector &	GetSchemaAttributeNames (bool includeInherited=true)
	Return a vector of names of all pre-declared attributes for this schema class and all its ancestor classes. More...

static PHYSXSCHEMA_API TfTokenVector	GetSchemaAttributeNames (bool includeInherited, const TfToken &instanceName)
	Return a vector of names of all pre-declared attributes for this schema class and all its ancestor classes for a given instance name. More...

static PHYSXSCHEMA_API PhysxSchemaPhysxTendonAttachmentRootAPI	Get (const UsdStagePtr &stage, const SdfPath &path)
	Return a PhysxSchemaPhysxTendonAttachmentRootAPI holding the prim adhering to this schema at `path` on `stage`. More...

static PHYSXSCHEMA_API PhysxSchemaPhysxTendonAttachmentRootAPI	Get (const UsdPrim &prim, const TfToken &name)
	Return a PhysxSchemaPhysxTendonAttachmentRootAPI with name `name` holding the prim `prim`. More...

static PHYSXSCHEMA_API std::vector < PhysxSchemaPhysxTendonAttachmentRootAPI >	GetAll (const UsdPrim &prim)
	Return a vector of all named instances of PhysxSchemaPhysxTendonAttachmentRootAPI on the given `prim`. More...

static PHYSXSCHEMA_API bool	IsSchemaPropertyBaseName (const TfToken &baseName)
	Checks if the given name `baseName` is the base name of a property of PhysxTendonAttachmentRootAPI. More...

static PHYSXSCHEMA_API bool	IsPhysxTendonAttachmentRootAPIPath (const SdfPath &path, TfToken *name)
	Checks if the given path `path` is of an API schema of type PhysxTendonAttachmentRootAPI. More...

static PHYSXSCHEMA_API bool	CanApply (const UsdPrim &prim, const TfToken &name, std::string *whyNot=nullptr)
	Returns true if this multiple-apply API schema can be applied, with the given instance name, `name`, to the given `prim`. More...

static PHYSXSCHEMA_API PhysxSchemaPhysxTendonAttachmentRootAPI	Apply (const UsdPrim &prim, const TfToken &name)
	Applies this multiple-apply API schema to the given `prim` along with the given instance name, `name`. More...

Static Public Attributes
static const UsdSchemaKind	schemaKind = UsdSchemaKind::MultipleApplyAPI
	Compile time constant representing what kind of schema this class is. More...

Protected Member Functions
PHYSXSCHEMA_API UsdSchemaKind	_GetSchemaKind () const override
	Returns the kind of schema this class belongs to. More...

Friends
class	UsdSchemaRegistry

Detailed Description

WARNING: Draft API, this design is not fixed and may change in the future.

Applied to an articulation-link rigid-body Xformable.

The root API creates a new spatial tendon tree. The root tendon attachment is the only attachment in a tendon tree that does not have a parent, so the parentLink, parentAttachment, and gearing attributes inherited from PhysxTendonAttachmentAPI are ignored for a root.

Spatial tendons create line-of-sight distance constraints between links of a single articulation. In particular, spatial tendons run through attachments that are positioned relative to a rigid-body link, and their length is defined as a weighted sum of the distance between the attachments in the tendon.

Spatial tendons may branch, in which case the tendon splits up into multiple conceptual sub-tendons, one for each root-to-leaf path in the tendon tree. The tendon tree starts at the root, and its topology is defined by the attachments' parentLink rel and parentAttachment token.

It is possible to create multiple attachments per link, see PhysxTendonAttachmentAPI.

Details on dynamics:

The length of a sub-tendon in the tree is

subTendonLength = sum(gearing[i] * |p[i] - p_parent[i]|)

where the sum is evaluated along the unique tree path between root and leaf. The gearing[i] is the i-th attachment's gearing, and |p[i] - p_parent[i]| is the distance between the positions of the i-th attachment and its parent attachment.

Each subtendon has spring-damper dynamics acting on the length constraint

constraint = 0 = offset + subTendonLength - restLength

where the offset is a common summand for all sub-tendons of a spatial tendon, and the restLength is specific to a sub-tendon, see the PhysxTendonAttachmentLeafAPI.

If limits are not active, the sub-tendon force that acts on the leaf is

F = stiffness * constraint + damping * tendonVelocity

where tendonVelocity is the sum of the time derivatives of the line-of-sight distances between 1) the leaf and its parent attachment and 2) the tendon root and its first child attachment on the path to the leaf. Stiffness and damping are common parameters for all sub-tendons.

The 3D force applied at the leaf attachment is equal to

F * (p_parent - p_leaf).

where p_leaf and p_parent are the leaf's position and its parent's position, respectively. The reaction force acting on the root attachment is

F * (p_child_leaf - p_root)

where p_child_leaf is the position of the root's child attachment that leads to the leaf that produces F, and p_root is the root attachment position. The tendon force is not further propagated through the tendon, so at intermediate attachments (i.e. created by PhysxTendonAttachmentAPI) no forces are applied.

Note that a spatial tendon may both pull and push on the leaf and root attachments. A string-like, one-sided constraint can be implemented using the sub-tendon's length limits.

Sub-tendon length limits constrain the offset length

lowerLimit <= subTendonLength + offset<= upperLimit

and, when active, add a restoring spring force parametrized by limitStiffness to the tendon force, analogous to the length constraint force above. Limit dynamics are damped by the tendon-length damping that is applied regardless of a limit being active. Limit parameters are attributes of the PhysxTendonAttachmentLeafAPI.

Definition at line 123 of file physxTendonAttachmentRootAPI.h.

Constructor & Destructor Documentation

PhysxSchemaPhysxTendonAttachmentRootAPI	(	const UsdPrim &	prim = `UsdPrim()`,
		const TfToken &	name = `TfToken()`
	)

inlineexplicit

Construct a PhysxSchemaPhysxTendonAttachmentRootAPI on UsdPrim prim with name name .

Equivalent to PhysxSchemaPhysxTendonAttachmentRootAPI::Get( prim.GetStage(), prim.GetPath().AppendProperty( "physxTendon:name"));

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

Definition at line 140 of file physxTendonAttachmentRootAPI.h.

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

inlineexplicit

Construct a PhysxSchemaPhysxTendonAttachmentRootAPI on the prim held by schemaObj with name name.

Should be preferred over PhysxSchemaPhysxTendonAttachmentRootAPI(schemaObj.GetPrim(), name), as it preserves SchemaBase state.

Definition at line 149 of file physxTendonAttachmentRootAPI.h.

virtual PHYSXSCHEMA_API ~PhysxSchemaPhysxTendonAttachmentRootAPI ( )

virtual

Destructor.

Member Function Documentation

PHYSXSCHEMA_API UsdSchemaKind _GetSchemaKind ( ) const

overrideprotected

Returns the kind of schema this class belongs to.

See Also: UsdSchemaKind

static PHYSXSCHEMA_API PhysxSchemaPhysxTendonAttachmentRootAPI 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 "PhysxTendonAttachmentRootAPI:<i>name</i>" to the token-valued, listOp metadata apiSchemas on the prim. For example, if name is 'instance1', the token 'PhysxTendonAttachmentRootAPI:instance1' is added to 'apiSchemas'.

Returns: A valid PhysxSchemaPhysxTendonAttachmentRootAPI object is returned upon success. An invalid (or empty) PhysxSchemaPhysxTendonAttachmentRootAPI 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()

static PHYSXSCHEMA_API bool 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()

PHYSXSCHEMA_API UsdAttribute CreateDampingAttr	(	VtValue const &	defaultValue = `VtValue()`,
		bool	writeSparsely = `false`
	)		const

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