GraphController

class omni.graph.core.GraphController(*args, **kwargs)

Bases: object

Helper class that provides a simple interface to modifying the contents of a graph

Methods

__init__(*args, **kwargs)	Initializes the class with a particular configuration.
connect(*args, **kwargs)	Create a connection between two attributes
create_graph(*args, **kwargs)	Create a graph from the description
create_node(*args, **kwargs)	Create an OmniGraph node of the given type and version at the given path.
create_prim(*args, **kwargs)	Create a prim node containing a predefined set of attribute values and a ReadPrim OmniGraph node for it
create_variable(*args, **kwargs)	Creates a variable with the given name on the graph
delete_node(*args, **kwargs)	Deletes one or more OmniGraph nodes.
disconnect(*args, **kwargs)	Break a connection between two attributes
disconnect_all(*args, **kwargs)	Break all connections to and from an attribute
expose_prim(*args, **kwargs)	Create a new compute node attached to an ordinary USD prim or list of prims.
exposed_attribute_name(exposure_type)	Returns the name of the attribute that will be used to expose the prim for a given exposure type
get_variable_default_value(variable_id)	Gets the default value of the given variable
node_type_to_expose(exposure_type)	Returns the type of node that will be used to expose the prim for a given exposure type
set_variable_default_value(variable_id, value)	Sets the default value of a variable object.

Attributes

ExposePrimNode_t(*args, **kwargs)	Typing for information required to expose a prim in a node
ExposePrimNodes_t(*args, **kwargs)	Typing for information required to expose a list of prims in nodes
PrimExposureType_t(*args, **kwargs)	Flexible type to specify how to expose the prim

__init__(*args, **kwargs)

Initializes the class with a particular configuration. The arguments are flexible so that classes can initialize only what they need for the calls they will be making. Both arguments are optional, and there may be other arguments present that will be ignored.

Parameters

• update_usd (bool) – Should any graphs, nodes, and prims referenced in operations be updated immediately to USD? (default True)

• undoable (bool) – If True the operations performed with this instance of the class are added to the undo queue, else they are done immediately and forgotten (default True)

• allow_exists_node – If True then succeed creation of a node when matching path, type, and version already exists. It is still a failure if one of those properties on the existing node does not match.

• allow_exists_prim – If True then succeed creation of a prim when matching path and type already exists. It is still a failure if type on the existing prim does not match.

class PrimExposureType(value)

Bases: Enum

Value that specifies the method of exposing USD prims to OmniGraph

AS_ATTRIBUTES = 'attributes'

Expose the prim via a node that creates outputs for all of the prim’s attributes

AS_BUNDLE = 'bundle'

Expose the prim via a node that creates a single output bundle with all of the prim’s attributes

AS_WRITABLE = 'writable'

Expose the prim to be written to via a node that creates inputs for the prim’s attributes

classmethod connect(*args, **kwargs)

Create a connection between two attributes

This function can be called either from the class or using an instantiated object. The first argument is positional, being either the class or object. All others are by keyword and optional, defaulting to the value set in the constructor in the object context and the function defaults in the class context.

Parameters

• obj – Either cls or self depending on how the function was called

• src_spec – Specification of the attribute to be the source end of the connection

• dst_spec – Specification of the attribute to be the destination end of the connection

• update_usd – If specified then override whether to delete the node’s USD backing (default True)

• undoable – If True the operation is added to the undo queue, else it is done immediately and forgotten (default True)

Raises

OmniGraphError – If attributes could not be found or the connection fails

classmethod create_graph(*args, **kwargs) → Graph

Create a graph from the description

This function can be called either from the class or using an instantiated object. The first argument is positional, being either the class or object. The second argument can be positional or by keyword and is mandatory, resulting in an error if omitted. All others are by keyword and optional, defaulting to the value set in the constructor in the object context and the function defaults in the class context.

new_graph = og.GraphController.create_graph("/TestGraph")
controller = og.GraphController(undoable=True)
controller.create_graph({"graph_path": "/UndoableGraph", "evaluator_name": "execution"})

Parameters

• obj – Either cls or self, depending on how the function was called

• graph_id –

  Parameters describing the graph to be created. If the graph is just a path then a default graph will be created at that location. If the identifier is a dictionary then it will be interpreted as a set of parameters describing the type of graph to create

  • graph_path: Full path to the graph prim to be created to house the OmniGraph

  • evaluator_name: Type of evaluator the graph should use (default push)

  • fc_backing_type: og.GraphBackingType that tells you what kind of Fabric to use for graph data (default og.GraphBackingType.GRAPH_BACKING_TYPE_FABRIC_SHARED)

  • pipeline_stage: og.GraphPipelineStage that tells you which pipeline stage this graph fits into (default og.GraphPipelineStage.GRAPH_PIPELINE_STAGE_SIMULATION)

  • evaluation_mode: og.GraphEvaluationMode that tells you which evaluation mode this graph uses (default og.GraphEvaluationMode.GRAPH_EVALUATION_MODE_AUTOMATIC)

• update_usd (bool) – If specified then override whether to create the graph with a USD backing (default True)

• undoable (bool) – If True the operation is added to the undo queue, else it is done immediately and forgotten (default True)

Returns

The created graph

Return type

omni.graph.core.Graph

Raises

OmniGraphError – if the graph creation failed for any reason

classmethod create_node(*args, **kwargs) → Graph

Create an OmniGraph node of the given type and version at the given path.

This function can be called either from the class or using an instantiated object. The first argument is positional, being either the class or object. “node_id” and “node_type_id” are mandatory, and can be specified either as positional or keyword arguments. All others are by keyword only and optional, defaulting to the value set in the constructor in the object context where available, and the function defaults elsewhere.

og.GraphController.create_node("/MyGraph/MyNode", "omni.graph.nodes.NodeType")
og.GraphController(update_usd=True).create_node("/MyGraph/MyNode", "omni.graph.nodes.NodeType")
og.GraphController.create_node("/MyGraph/MyNode", "omni.graph.nodes.NodeType", update_usd=True)
og.GraphController.create_node(node_id="/MyGraph/MyNode", node_type="omni.graph.nodes.NodeType")

Parameters

• obj – Either cls or self, depending on how the function was called

• node_id – Absolute path, or (Relative Path, Graph) where the node will be constructed. If an absolute path was passed in it must be part of an existing graph.

• node_type_id – Unique identifier for the type of node to create (name or og.NodeType)

• allow_exists – If True then succeed if a node with matching path, type, and version already exists. It is still a failure if one of those properties on the existing node does not match.

• version – Version of the node type to create. By default it creates the most recent.

• update_usd – If specified then override whether to create the node with a USD backing or not (default True)

• undoable – If True the operation is added to the undo queue, else it is done immediately and forgotten (default True)

Raises

og.OmniGraphError – If one or more of the nodes could not be added to the scene for some reason.

Returns

Node(s) added to the scene

Return type

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

classmethod create_prim(*args, **kwargs) → Prim

Create a prim node containing a predefined set of attribute values and a ReadPrim OmniGraph node for it

This function can be called either from the class or using an instantiated object. The first argument is positional, being either the class or object. The “prim_path” is mandatory and can appear as either a positional or keyword argument. All others are optional, also by position or keyword, defaulting to the value set in the constructor in the object context if available, and the function defaults elsewhere.

og.GraphController.create_prim("/MyPrim")
og.GraphController(undoable=False).create_prim("/MyPrim", undoable=True)  # Will be undoable
og.GraphController().create_prim(prim_path="/MyPrim", prim_type="MyPrimType")
og.GraphController.create_prim("/MyPrim", )

Parameters

• obj – Either cls or self depending on how the function was called

• prim_path – Location of the prim

• attribute_values – Dictionary of {NAME: (TYPE, VALUE)} for all prim attributes The TYPE recognizes OGN format, SDF format, or og.Type values The VALUE should be in a format suitable for passing to pxr::UsdAttribute.Set()

• prim_type – The type of prim to create. (default “OmniGraphPrim”)

• allow_exists – If True then succeed if a prim with matching path and type already exists. It is still a failure if type on the existing prim does not match.

• undoable – If True the operation is added to the undo queue, else it is done immediately and forgotten (default True)

Returns

Prim created

Return type

Usd.Prim

Raises

OmniGraphError – If any of the attribute specifications could not be applied to the prim, or if the prim could not be created.

classmethod create_variable(*args, **kwargs) → IVariable

Creates a variable with the given name on the graph

This function can be called either from the class or using an instantiated object. The first argument is positional, being either the class or object. All others are by keyword and optional, defaulting to the value set in the constructor in the object context and the function defaults in the class context.

Parameters

• graph_id – The graph to create a variable on

• name – The name of the variable to create

• var_type – The type of the variable to create, either a string or an OG.Type

• undoable – If True the operation is added to the undo queue, else it is done immediately and forgotten (default True)

• default_value – The default value of the variable to set, or None to not set a default value. (default None)

Raises

OmniGraphError – If the variable can’t be created

Returns

The created variable

Return type

omni.graph.core.IVariable

classmethod delete_node(*args, **kwargs) → bool

Deletes one or more OmniGraph nodes.

This function can be called either from the class or using an instantiated object. The first argument is positional, being either the class or object. All others are by keyword and optional, defaulting to the value set in the constructor in the object context and the function defaults in the class context.

Parameters

• obj – Either cls or self depending on how the function was called

• node_id – Specification of a node or list of nodes to be deleted

• graph_id – Only required if the node_id does not contain enough information to uniquely identify it

• ignore_if_missing – If True then succeed even if no node with a matching path exists

• update_usd – If specified then override whether to delete the node’s USD backing (default True)

• undoable – If True the operation is added to the undo queue, else it is done immediately and forgotten (default True)

Raises

OmniGraphError – If the node does not exist

Returns

True if the node was successfully deleted

Return type

bool

classmethod disconnect(*args, **kwargs)

Break a connection between two attributes

This function can be called either from the class or using an instantiated object. The first argument is positional, being either the class or object. All others are by keyword and optional, defaulting to the value set in the constructor in the object context and the function defaults in the class context.

Parameters

• obj – Either cls or self depending on how the function was called

• src_spec – Specification of the attribute that is the source end of the connection

• dst_spec – Specification of the attribute that is the destination end of the connection

• update_usd – If specified then override whether to delete the node’s USD backing (default True)

• undoable – If True the operation is added to the undo queue, else it is done immediately and forgotten (default True)

Raises

OmniGraphError – If attributes could not be found or the disconnection fails

classmethod disconnect_all(*args, **kwargs)

Break all connections to and from an attribute

This function can be called either from the class or using an instantiated object. The first argument is positional, being either the class or object. All others are by keyword and optional, defaulting to the value set in the constructor in the object context and the function defaults in the class context.

Parameters

• obj – Either cls or self depending on how the function was called

• attribute_spec – Attribute whose connections are to be removed. (attr or (attr, node) pair)

• update_usd – If specified then override whether to delete the node’s USD backing (default True)

• undoable – If True the operation is added to the undo queue, else it is done immediately and forgotten (default True)

Raises

OmniGraphError – If attribute could not be found, connection didn’t exist, or disconnection fails

classmethod expose_prim(*args, **kwargs) → Node

Create a new compute node attached to an ordinary USD prim or list of prims.

This function can be called either from the class or using an instantiated object. The first argument is positional, being either the class or object. All others are by keyword and optional, defaulting to the value set in the constructor in the object context and the function defaults in the class context.

Parameters

• obj – Either cls or self depending on how the function was called

• exposure_type – Method for exposing the prim to OmniGraph

• prim_id – Identifier of an existing prim in the USD stage

• node_path_id – Identifier of a node path that is valid but does not currently exist

• update_usd – If specified then override whether to delete the node’s USD backing (default True)

• undoable – If True the operation is added to the undo queue, else it is done immediately and forgotten (default True)

Returns

Node exposing the prim to OmniGraph

Return type

omni.graph.core.Node

Raises

og.OmniGraphError – if the prim does not exist, or the node path already exists

classmethod exposed_attribute_name(exposure_type: PrimExposureType_t) → str

Returns the name of the attribute that will be used to expose the prim for a given exposure type

Parameters

exposure_type – Type of exposure desired

Returns

Name of the attribute at which a connection should be made to the prim for exposure

Return type

str

classmethod get_variable_default_value(variable_id: str | pxr.Sdf.Path | omni.graph.core._omni_graph_core.IVariable | tuple[str | pxr.Sdf.Path | omni.graph.core._omni_graph_core.Graph | pxr.Usd.Prim | pxr.Usd.Typed, str]) → Any

Gets the default value of the given variable

Parameters

variable_id – The variable whose value is to be set

Returns

The default value of the variable.

Return type

Any

Raises

OmniGraphError – If the variable is not valid or does not have valid usd backing.

classmethod node_type_to_expose(exposure_type: PrimExposureType_t) → str

Returns the type of node that will be used to expose the prim for a given exposure type

Parameters

exposure_type – Type of exposure desired

Returns

Node type of the appropriate omni.graph.core.Node to use to expose the prim

Return type

str

classmethod set_variable_default_value(variable_id: str | pxr.Sdf.Path | omni.graph.core._omni_graph_core.IVariable | tuple[str | pxr.Sdf.Path | omni.graph.core._omni_graph_core.Graph | pxr.Usd.Prim | pxr.Usd.Typed, str], value)

Sets the default value of a variable object.

Parameters

• variable_id – The variable whose value is to be set

• value – The value to set

Raises

• OmniGraphError – If the variable is not valid, does not have valid usd backing, or value

• is not a compatible type –

ExposePrimNode_t(*args, **kwargs)

Typing for information required to expose a prim in a node

alias of Tuple[str | Path | Node | Prim | Typed | Graph, str | Path | tuple[str | Path | Graph | Prim | Typed]]

ExposePrimNodes_t(*args, **kwargs)

Typing for information required to expose a list of prims in nodes

alias of Union[Tuple[str | Path | Node | Prim | Typed | Graph, str | Path | tuple[str | Path | Graph | Prim | Typed]], List[Tuple[str | Path | Node | Prim | Typed | Graph, str | Path | tuple[str | Path | Graph | Prim | Typed]]]]

PrimExposureType_t(*args, **kwargs)

Flexible type to specify how to expose the prim

alias of Union[str, PrimExposureType]