ObjectLookup#

class omni.graph.core.ObjectLookup#

Bases: object

Helper to extract OmniGraph types from various types of descriptions for them.

These functions take flexible spec types that identify attributes, nodes, or graphs. In most cases the spec types can be either one of or a list of the objects being used or found by the functions. The forms each spec type can take are as follows:

GraphSpec_t

An omni.graph.core.Graph object
A string containing the path to an omni.graph.core.Graph object
An Sdf.Path containing the path to an omni.graph.core.Graph object
A list of any of the above

NodeSpec_t

An omni.graph.core.Node object
A string containing the path to an omni.graph.core.Node object
An Sdf.Path containing the path to an omni.graph.core.Node object
A Usd.Prim or Usd.Typed that is the USD backing of an omni.graph.core.Node object
None, for situations in which the node itself is redundant information
A 2-tuple consisting of a string and a omni.graph.core.GraphSpec_t, where the string is a relative path to the omni.graph.core.Node object within the omni.graph.core.Graph
A list of any of the above

AttributeSpec_t

An omni.graph.core.Attribute object
A string containing the full path to the omni.graph.core.Attribute object on the USD stage
An Sdf.Path containing the full path to the omni.graph.core.Attribute object on the USD stage
A Usd.Attribute or Usd.Relationship that is the USD backing of an omni.graph.core.Attribute object
A 2-tuple consisting of a string and a NodeSpec_t, where the string is the omni.graph.core.Attribute object’s name within the omni.graph.core.Node
A list of any of the above

Prim_t

A Usd.Prim or Usd.Typed object
A string containing the path to a Usd.Prim or Usd.Typed object
An Sdf.Path containing the path to a Usd.Prim or Usd.Typed object
A NodeSpec_t, identifying a node whose USD backing Usd.Prim or Usd.Typed object is to be returned
A list of any of the above

Variables_t

An omni.graph.core.IVariable object
A 2-tuple consisting of a omni.graph.core.GraphSpec_t and a string, where the string is the name of the variable
A string containing the path of the attribute representing the variable
An Sdf.Path containing the path of the attribute representing the variable
A list of any of the above

Methods

`attribute`(attribute_id[, node_id, graph_id])	Returns the OmniGraph attribute(s) corresponding to the variable type parameter
`attribute_path`(attribute_spec)	Infers an attribute path from a spec where the attribute may or may not exist
`attribute_type`(type_id)	Returns the OmniGraph attribute type corresponding to the variable type parameter.
`compound_graph`(node_id)	Returns the compound graph of a given node or nodes, or None if the node does not contain a compound graph
`compound_node`(item_id)	Returns the owning compound node for a given graph, or node, or None if the graph or node is not encapsulated by a compound node
`graph`(graph_id)	Returns the OmniGraph graph(s) corresponding to the variable type parameter
`node`(node_id[, graph_id])	Returns the OmniGraph node(s) corresponding to the variable type parameter
`node_path`(node_spec)	Infers a node path from a spec where the node may or may not exist
`node_type`(type_id)	Returns the OmniGraph node type corresponding to the variable type parameter
`prim`(prim_id)	Returns the prim(s) corresponding to the node descriptions
`prim_path`(prim_ids)	Infers a prim path from a spec where the prim may or may not exist
`split_graph_from_node_path`(node_path)	Find the lowest level graph from a node path
`usd_attribute`(attribute_specs)	Returns the Usd.Attribute(s) corresponding to the attribute descriptions
`usd_property`(attribute_specs)	Returns the Usd.Property(s) corresponding to the attribute descriptions
`usd_relationship`(attribute_specs)	Returns the Usd.Relationships(s) corresponding to the attribute descriptions
`variable`(variable_id)	Returns the variables(s) corresponding to the variable description

__init__()#

Returns the OmniGraph attribute(s) corresponding to the variable type parameter

Parameters:

attribute_id –
Information on which attribute to look for. If a list then get all of them. The attribute_id can take one of several forms, for maximum flexibility:
- a 2-tuple consisting of the attribute name as str and a node spec. The named attribute must exist on the node - e.g. (“inputs:value”, my_node) or (“inputs:value”, “/Graph/MyNode”). This is equivalent to passing in the attribute and node spec as two different parameters. You’d use this form when requesting several attributes from different nodes rather than a bunch of attributes from the same node.
- a str or Sdf.Path pointing directly to the attribute - e.g. “/Graph/MyNode/inputs:value”
- a str that’s an attribute name, iff the node_id is also specified
- a Usd.Attribute or Usd.Relationship pointing to the attribute’s reference on the USD side
node_id – Node to which the attribute belongs, when only the attribute’s name is provided
graph_id – Graph to which the node and attribute belong.

Returns:

Attribute(s) matching the description(s) - None where there is no match

Raises:

OmniGraphError – if the attribute description wasn’t one of the recognized types, if any of the attributes could not be found, or if there was a mismatch in node or graph and attribute.

Infers an attribute path from a spec where the attribute may or may not exist

Parameters:: attribute_spec – Location of where the attribute would be, if it exists
Returns:: Location of the attribute, if it exists
Return type:: str
Raises:: OmniGraphError – If there was something inconsistent in the attribute spec or a path could not be inferred

classmethod attribute_type( type_id: str | Type | Attribute | AttributeData, ) → Type#

Returns the OmniGraph attribute type corresponding to the variable type parameter.

All legal OGN types are recognized, as well as the UNKNOWN type.

Parameters:

type_id –

Variable description of the attribute type object as one of:

An omni.graph.core.Type object
An OGN-style type description - e.g. “float[3]”
An Sdf-style type description - e.g. “float3”
An omni.graph.core.Attribute whose (resolved) type is to be retrieved
An omni.graph.core.AttributeData whose (resolved) type is to be retrieved

Returns:

Attribute type matching the description

Return type:

omni.graph.core.Type

Raises:

OmniGraphError – if the attribute type description wasn’t one of the recognized types

Returns the compound graph of a given node or nodes, or None if the node does not contain a compound graph

Parameters:

node_id –

Information for the node to find. If a list then iterate over the list

Returns:

omni.graph.core.Graph | None | list[omni.graph.core.Graph | None]: The compound graph instances: the contained by the given nodes. If node does not encapsulate a compound graph, the value None is returned.

Raises:

omni.graph.core.OmniGraphError: node_id description wasn’t a recognized type

Returns the owning compound node for a given graph, or node, or None if the graph or node is not encapsulated by a compound node

Parameters:: item_id – The graph, node, or list of graphs and nodes, to retrieve the owning compound node(s) for.
Returns:: The compound node(s) that encapsulate the provided graph(s), or None if the graph(s) are not encapsulated by a compound node
Return type:: omni.graph.core.Node | None | list[omni.graph.core.Node | None]
Raises:: omni.graph.core.OmniGraphError – The provided graphs or nodes are invalid or unrecognized types.

Returns the OmniGraph graph(s) corresponding to the variable type parameter

Parameters:

graph_id – Information for the graph to find. If a list then iterate over the list

Returns:

Graph(s) corresponding to the description(s) in the: current scene, None where there is no match

Return type:

omni.graph.core.Graph | list[omni.graph.core.Graph]

Raises:

OmniGraphError – if a graph matching the identifier wasn’t found

Returns the OmniGraph node(s) corresponding to the variable type parameter

Parameters:

node_id – Information for the node to find. If a list then iterate over the list
graph_id – Identifier for graph to which the node belongs.

Returns:

Node(s) corresponding to the description(s) in the: current graph, None where there is no match

Return type:

omni.graph.core.Node | list[omni.graph.core.Node]

Raises:

OmniGraphError – node description wasn’t a recognized type or if a mismatched graph was passed in
og.OmniGraphValueError – If the node description did not match a node in the graph

Infers a node path from a spec where the node may or may not exist

Parameters:: node_spec – Description of a path to a node that may or may not exist
Returns:: The path inferred from the node spec. No assumption should be made about the validity of the path.
Return type:: str
Raises:: OmniGraphError – If there was something inconsistent in the node spec or a path could not be inferred

Returns the OmniGraph node type corresponding to the variable type parameter

Parameters:

type_id – Information used to identify the omni.graph.core.NodeType object; it will be one of:
object (- an omni.graph.core.NodeType)
type (- a string that is the unique identifier of the node)
returned (- a Usd.Prim or Usd.Typed that is the USD backing of an omni.graph.core.Node whose type is to be)
returned
above (- a list of any combination of the)

Returns:

Node type(s) matching the description

Return type:

omni.graph.core.NodeType | list[omni.graph.core.NodeType]

Raises:

OmniGraphError – if the node type description wasn’t one of the recognized types or could not be found

Returns the prim(s) corresponding to the node descriptions

Parameters:

prim_id – Information for the node to find. If a list then iterate over the list

Returns:

Prim(s) corresponding to the description(s) in the current graph,: None where there is no match

Return type:

Usd.Prim | list[Usd.Prim]

Raises:

OmniGraphError – if the node description(s) didn’t correspond to a valid prim(s).

Infers a prim path from a spec where the prim may or may not exist

Parameters:: prim_ids – Identifier of a prim or list of prims that may or may not exist
Returns:: Path(s) inferred from the prim spec(s). No assumption should be made about their validity.
Return type:: str | list[str]
Raises:: OmniGraphError – If there was something inconsistent in the prim spec or a path could not be inferred

classmethod split_graph_from_node_path( node_path: str | Path, ) → Tuple[Graph, str]#

Find the lowest level graph from a node path

The path /World/Graph1/Graph2/Node1/Node2 would return the og.Graph at /World/Graph1/Graph2 and the relative node path “Node1/Node2”.

Parameters:

node_path – Full path to the node from the root

Returns:

where graph is the lowest graph in the tree and node_path is the: relative path to the node from the graph

Return type:

tuple[omni.graph.core.Graph, str]

Returns the Usd.Attribute(s) corresponding to the attribute descriptions

Parameters:: attribute_specs – Location or list of locations from which to infer a matching Usd.Attribute
Returns:: Usd.Attribute(s) corresponding to the description(s) in the USD stage
Return type:: Usd.Attribute | list[Usd.Attribute]
Raises:: OmniGraphError – if the attribute description didn’t correspond to a valid Usd.Attribute.

Returns the Usd.Property(s) corresponding to the attribute descriptions

Parameters:: attribute_specs – Location or list of locations from which to infer a matching Usd.Property
Returns:: Usd.Property(s) corresponding to the description(s) in the USD stage
Return type:: Usd.Property | list[Usd.Property]
Raises:: OmniGraphError – if the attribute description didn’t correspond to a valid Usd.Property.

Returns the Usd.Relationships(s) corresponding to the attribute descriptions

Parameters:: attribute_specs – Location or list of locations from which to infer a matching Usd.Attribute
Returns:: Usd.Relationship(s) corresponding to the description(s) in the USD stage
Return type:: Usd.Relationship | list[Usd.Relationship]
Raises:: OmniGraphError – if the attribute description didn’t correspond to a valid Usd.Relationship.

Returns the variables(s) corresponding to the variable description

Parameters:

variable_id – Information for the variable to find. If a list then iterate over the list

Returns:

Variables(s) corresponding to the: description(s) in the current graph, None where there is no match

Return type:

omni.graph.core.IVariable | list[omni.graph.core.IVariable]

Raises:

OmniGraphError – if the variable description didn’t correspond to a valid variable