Isaac Sim | OmniGraph | Python API - Make array

omers · June 4, 2023, 1:11pm

Hello,

We are trying to programmatically use a make array (ConstructArray), but we are unable to set anything which is not input0.

Error:

2023-06-04 13:09:54 [1,965,188ms] [Error] [omni.kit.app.plugin] [py stderr]: OmniGraphError: Failed trying to look up attribute with (/nakai_container/MovementGraph/velocity_command_duplicator.inputs:input1, node=None, graph=None)

At:
  /home/amram/.local/share/ov/pkg/isaac_sim-2022.2.1/kit/exts/omni.graph/omni/graph/core/_impl/object_lookup.py(404): __attribute_from_info
  /home/amram/.local/share/ov/pkg/isaac_sim-2022.2.1/kit/exts/omni.graph/omni/graph/core/_impl/object_lookup.py(411): attribute
  /home/amram/.local/share/ov/pkg/isaac_sim-2022.2.1/kit/exts/omni.graph/omni/graph/core/_impl/controller.py(649): _process_set_value
  /home/amram/.local/share/ov/pkg/isaac_sim-2022.2.1/kit/exts/omni.graph/omni/graph/core/_impl/controller.py(656): <listcomp>
  /home/amram/.local/share/ov/pkg/isaac_sim-2022.2.1/kit/exts/omni.graph/omni/graph/core/_impl/controller.py(656): _process_set_values
  /home/amram/.local/share/ov/pkg/isaac_sim-2022.2.1/kit/exts/omni.graph/omni/graph/core/_impl/controller.py(1031): __do_the_edits
  /home/amram/.local/share/ov/pkg/isaac_sim-2022.2.1/kit/exts/omni.graph/omni/graph/core/_impl/controller.py(1038): __edit

Reproduction script:

import omni.graph.core as og

keys = og.Controller.Keys

og.Controller.edit(
    {"graph_path": "/nakai_container/MovementGraph", "evaluator_name": "execution"},
    {
        keys.CREATE_NODES: [
            ("velocity_command_duplicator", "omni.graph.nodes.ConstructArray"),
        ],
        keys.SET_VALUES: [
            ("velocity_command_duplicator.inputs:arraySize", 4),           
            ("velocity_command_duplicator.inputs:arrayType", "double[]"),
            ("velocity_command_duplicator.inputs:input0",  1),
            ("velocity_command_duplicator.inputs:input1",  2),
            ("velocity_command_duplicator.inputs:input2",  3),
            ("velocity_command_duplicator.inputs:input3",  4),
        ]
    },
)

In the GUI, there is the plus button for adding inputs, but how can it be done via the python api?

rthaker · June 9, 2023, 6:23pm

Hi @omers - It seems like the script is not able to find the attribute for the input1 of the velocity_command_duplicator node. This error could be caused by the node not being created properly before trying to set its input values.

To fix this issue, you can try splitting the creation and setting of values into two separate calls to the og.Controller.edit() method. Here’s the modified script:

import omni.graph.core as og

keys = og.Controller.Keys

Create the node first

og.Controller.edit(
{“graph_path”: “/nakai_container/MovementGraph”, “evaluator_name”: “execution”},
{
keys.CREATE_NODES: [
(“velocity_command_duplicator”, “omni.graph.nodes.ConstructArray”),
],
},
)

Set the input values for the created node

og.Controller.edit(
{“graph_path”: “/nakai_container/MovementGraph”, “evaluator_name”: “execution”},
{
keys.SET_VALUES: [
(“velocity_command_duplicator.inputs:arraySize”, 4),
(“velocity_command_duplicator.inputs:arrayType”, “double”),
(“velocity_command_duplicator.inputs:input0”, 1),
(“velocity_command_duplicator.inputs:input1”, 2),
(“velocity_command_duplicator.inputs:input2”, 3),
(“velocity_command_duplicator.inputs:input3”, 4),
],
},
)

Let us know if it works or not.

omers · June 18, 2023, 1:48pm

@rthaker Thanks for the detailed response.

First part creating the node working, second part trying to edit it throws the following exception:

2023-06-18 13:47:47 [270,818ms] [Error] [omni.kit.app.plugin] [py stderr]: OmniGraphError: Failed to wrap graph in node given {'graph_path': '/nakai_container/MovementGraph', 'evaluator_name': 'execution'}

At:
  /home/amram/.local/share/ov/pkg/isaac_sim-2022.2.1/kit/exts/omni.graph/omni/graph/core/_impl/graph_controller.py(172): __create_graph
  /home/amram/.local/share/ov/pkg/isaac_sim-2022.2.1/kit/exts/omni.graph/omni/graph/core/_impl/graph_controller.py(106): create_graph
  /home/amram/.local/share/ov/pkg/isaac_sim-2022.2.1/kit/exts/omni.graph/omni/graph/core/_impl/controller.py(939): __do_the_edits
  /home/amram/.local/share/ov/pkg/isaac_sim-2022.2.1/kit/exts/omni.graph/omni/graph/core/_impl/controller.py(1038): __edit
  /home/amram/.local/share/ov/pkg/isaac_sim-2022.2.1/kit/exts/omni.graph/omni/graph/core/_impl/controller.py(878): edit
  /tmp/carb.mOqQgg/script_1687096067.py(14): <module>

rthaker · July 6, 2023, 9:10pm

Hi @omers - Can you try this other script? if it doesn’t work then I will bring this issue to the Omnigraph experts.

import omni.graph.core as og

keys = og.Controller.Keys

og.Controller.edit(
    {"graph_path": "/nakai_container/MovementGraph", "evaluator_name": "execution"},
    {
        keys.CREATE_NODES: [
            ("velocity_command_duplicator", "omni.graph.nodes.ConstructArray"),
        ],
        keys.SET_VALUES: [
            ("velocity_command_duplicator.inputs:arraySize", 4),
            ("velocity_command_duplicator.inputs:arrayType", "double[]"),
            ("velocity_command_duplicator.inputs:input0", 1),
        ]
    },
)

# Create a separate node or function to set the values of the other array elements
for i in range(1, 4):
    og.Controller.edit(
        {"graph_path": "/nakai_container/MovementGraph", "evaluator_name": "execution"},
        {
            keys.SET_VALUES: [
                (f"velocity_command_duplicator.inputs:input{i}", i + 1),
            ]
        },
    )

mino4 · April 15, 2024, 2:58am

I am also experiencing the same issue. When creating a MakeArray omnigraph node using a Python script, the inputs value is not being added, and the problem was not resolved even when I used the suggested method. I would like to know if there is another way.

    og.Controller.Keys.SET_VALUES: [
        ("DifferentialController.inputs:wheelDistance", 0.53342),
        ("DifferentialController.inputs:wheelRadius", 0.24),
        ("MakeArray.inputs:arraySize", 2),
        ("MakeArray.inputs:arrayType", "token[]"),
        ("MakeArray.inputs:input0", "left_wheel"),
        ("MakeArray.inputs:input1", "right_wheel"),
        ("ArticulationController.inputs:targetPrim", "/World/Robot"),
        ("ArticulationController.inputs:usePath", False),
    ],

guangping.liu · August 8, 2024, 9:40pm

Same thing and it also doesn’t work for me.

hijikata_M · August 9, 2024, 1:45am

Another approach is to use og.Controller.attribute().
https://docs.omniverse.nvidia.com/isaacsim/latest/advanced_tutorials/tutorial_advanced_omnigraph_scripting.html?highlight=graph#editing-a-graph
Example:

import omni.graph.core as og

keys = og.Controller.Keys

og.Controller.edit(
    {"graph_path": "/nakai_container/MovementGraph", "evaluator_name": "execution"},
    {
        keys.CREATE_NODES: [
            ("velocity_command_duplicator", "omni.graph.nodes.ConstructArray"),
        ],
        keys.SET_VALUES: [
            ("velocity_command_duplicator.inputs:arraySize", 4),
            ("velocity_command_duplicator.inputs:arrayType", "double[]"),
        ]
    },
)

og.Controller.attribute("/nakai_container/MovementGraph/velocity_command_duplicator.inputs:input0").set(1)
og.Controller.attribute("/nakai_container/MovementGraph/velocity_command_duplicator.inputs:input1").set(2)
og.Controller.attribute("/nakai_container/MovementGraph/velocity_command_duplicator.inputs:input2").set(3)
og.Controller.attribute("/nakai_container/MovementGraph/velocity_command_duplicator.inputs:input3").set(4)

bren1 · October 28, 2024, 10:08pm

Did anyone get this to work? I’m still can’t get it to work using the examples posted.

When I set the array size to 2 it shows 2 in the input but the GUI still only shows a single input and input0 is just repeated in both arrays.

og.Controller.edit(
        {"graph_path": f"{ROBOT_STAGE_PATH}/ROS/DifferentialController", "evaluator_name": "execution"},
        {
            # fmt: off
            og.Controller.Keys.CREATE_NODES: [
                ("OnPlaybackTick", "omni.graph.action.OnPlaybackTick"),
                ("Context", "omni.isaac.ros2_bridge.ROS2Context"),
                ("ROS2SubscribeTwist", "omni.isaac.ros2_bridge.ROS2SubscribeTwist"),
                ("ArticulationController", "omni.isaac.core_nodes.IsaacArticulationController"),
                ("DifferentialController", "omni.isaac.wheeled_robots.DifferentialController"),

                ("cmd_vel_z", "omni.graph.nodes.BreakVector3"),
                ("cmd_vel_x", "omni.graph.nodes.BreakVector3"),
                ("wheel_names_array", "omni.graph.nodes.ConstructArray"),

            ],
            og.Controller.Keys.CONNECT: [
                ("OnPlaybackTick.outputs:tick", "ArticulationController.inputs:execIn"),
                ("OnPlaybackTick.outputs:tick", "DifferentialController.inputs:execIn"),
                ("OnPlaybackTick.outputs:tick", "ROS2SubscribeTwist.inputs:execIn"),

                ("Context.outputs:context", "ROS2SubscribeTwist.inputs:context"),

                ("DifferentialController.outputs:velocityCommand", "ArticulationController.inputs:velocityCommand"),

                ("ROS2SubscribeTwist.outputs:angularVelocity", "cmd_vel_z.inputs:tuple"),
                ("ROS2SubscribeTwist.outputs:linearVelocity", "cmd_vel_x.inputs:tuple"),

                ("cmd_vel_z.outputs:z", "DifferentialController.inputs:angularVelocity"),
                ("cmd_vel_x.outputs:x", "DifferentialController.inputs:linearVelocity"),

                ("wheel_names_array.outputs:array", "ArticulationController.inputs:jointNames"),

            ],
            og.Controller.Keys.SET_VALUES: [
                ("Context.inputs:domain_id", ROS_DOMAIN_ID),

                ("ROS2SubscribeTwist.inputs:topicName", "cmd_vel"),

                ("ArticulationController.inputs:robotPath", f"{ROBOT_STAGE_PATH}/base_footprint"),
                ("ArticulationController.inputs:targetPrim", f"{ROBOT_STAGE_PATH}/base_footprint"),

                ("DifferentialController.inputs:wheelRadius", 0.0885),
                ("DifferentialController.inputs:wheelDistance", 0.46),
                ("DifferentialController.inputs:maxLinearSpeed", 0.6),
                ("DifferentialController.inputs:maxAngularSpeed", 0.6),

                ("wheel_names_array.inputs:arraySize", 2),
                ("wheel_names_array.inputs:arrayType", "token[]"),
                ("wheel_names_array.inputs:input0", "left_wheel_joint"),
                ("wheel_names_array.inputs:input1", "right_wheel_joint"),
            ],
        },
    )

hijikata_M · November 5, 2024, 6:44am

Could you try this?

og.Controller.edit(
        {"graph_path": f"{ROBOT_STAGE_PATH}/ROS/DifferentialController", "evaluator_name": "execution"},
        {
            # fmt: off
            og.Controller.Keys.CREATE_NODES: [
                ("OnPlaybackTick", "omni.graph.action.OnPlaybackTick"),
                ("Context", "omni.isaac.ros2_bridge.ROS2Context"),
                ("ROS2SubscribeTwist", "omni.isaac.ros2_bridge.ROS2SubscribeTwist"),
                ("ArticulationController", "omni.isaac.core_nodes.IsaacArticulationController"),
                ("DifferentialController", "omni.isaac.wheeled_robots.DifferentialController"),

                ("cmd_vel_z", "omni.graph.nodes.BreakVector3"),
                ("cmd_vel_x", "omni.graph.nodes.BreakVector3"),
                ("wheel_names_array", "omni.graph.nodes.ConstructArray"),

            ],
            og.Controller.Keys.CONNECT: [
                ("OnPlaybackTick.outputs:tick", "ArticulationController.inputs:execIn"),
                ("OnPlaybackTick.outputs:tick", "DifferentialController.inputs:execIn"),
                ("OnPlaybackTick.outputs:tick", "ROS2SubscribeTwist.inputs:execIn"),

                ("Context.outputs:context", "ROS2SubscribeTwist.inputs:context"),

                ("DifferentialController.outputs:velocityCommand", "ArticulationController.inputs:velocityCommand"),

                ("ROS2SubscribeTwist.outputs:angularVelocity", "cmd_vel_z.inputs:tuple"),
                ("ROS2SubscribeTwist.outputs:linearVelocity", "cmd_vel_x.inputs:tuple"),

                ("cmd_vel_z.outputs:z", "DifferentialController.inputs:angularVelocity"),
                ("cmd_vel_x.outputs:x", "DifferentialController.inputs:linearVelocity"),

                ("wheel_names_array.outputs:array", "ArticulationController.inputs:jointNames"),

            ],
            og.Controller.Keys.SET_VALUES: [
                ("Context.inputs:domain_id", ROS_DOMAIN_ID),

                ("ROS2SubscribeTwist.inputs:topicName", "cmd_vel"),

                ("ArticulationController.inputs:robotPath", f"{ROBOT_STAGE_PATH}/base_footprint"),
                ("ArticulationController.inputs:targetPrim", f"{ROBOT_STAGE_PATH}/base_footprint"),

                ("DifferentialController.inputs:wheelRadius", 0.0885),
                ("DifferentialController.inputs:wheelDistance", 0.46),
                ("DifferentialController.inputs:maxLinearSpeed", 0.6),
                ("DifferentialController.inputs:maxAngularSpeed", 0.6),

                ("wheel_names_array.inputs:arraySize", 2),
                ("wheel_names_array.inputs:arrayType", "token[]"),
            ],
        },
    )

og.Controller.attribute(f"{ROBOT_STAGE_PATH}/ROS/DifferentialController/wheel_names_array.inputs:input0").set("left_wheel_joint")
og.Controller.attribute(f"{ROBOT_STAGE_PATH}/ROS/DifferentialController/wheel_names_array.inputs:input1").set("right_wheel_joint")

bren1 · November 5, 2024, 9:18pm

This is isaac sim 4.2.0

I tired the code and didn’t work:

OmniGraphError: Failed trying to look up attribute with (/KR1/ROS/DifferentialController/wheel_names_array.inputs:input1, node=None, graph=None)

If still only has a single input on the graph. Does your graph have 2 inputs?

chengkun_li · December 12, 2024, 11:14am

I found a way to circumvent this problem

og.Controller.edit(
        {"graph_path": f"{ROBOT_STAGE_PATH}/ROS/DifferentialController", "evaluator_name": "execution"},
        {
            # fmt: off
            og.Controller.Keys.CREATE_NODES: [
                ("OnPlaybackTick", "omni.graph.action.OnPlaybackTick"),
                ("Context", "omni.isaac.ros2_bridge.ROS2Context"),
                ("ROS2SubscribeTwist", "omni.isaac.ros2_bridge.ROS2SubscribeTwist"),
                ("ArticulationController", "omni.isaac.core_nodes.IsaacArticulationController"),
                ("DifferentialController", "omni.isaac.wheeled_robots.DifferentialController"),

                ("cmd_vel_z", "omni.graph.nodes.BreakVector3"),
                ("cmd_vel_x", "omni.graph.nodes.BreakVector3"),
                ("wheel_names_array", "omni.graph.nodes.ConstructArray"),
                ("wheel_names_array_add", "omni.graph.nodes.ArrayInsertValue"),
            ],
            og.Controller.Keys.CONNECT: [
                ("OnPlaybackTick.outputs:tick", "ArticulationController.inputs:execIn"),
                ("OnPlaybackTick.outputs:tick", "DifferentialController.inputs:execIn"),
                ("OnPlaybackTick.outputs:tick", "ROS2SubscribeTwist.inputs:execIn"),

                ("Context.outputs:context", "ROS2SubscribeTwist.inputs:context"),

                ("DifferentialController.outputs:velocityCommand", "ArticulationController.inputs:velocityCommand"),

                ("ROS2SubscribeTwist.outputs:angularVelocity", "cmd_vel_z.inputs:tuple"),
                ("ROS2SubscribeTwist.outputs:linearVelocity", "cmd_vel_x.inputs:tuple"),

                ("cmd_vel_z.outputs:z", "DifferentialController.inputs:angularVelocity"),
                ("cmd_vel_x.outputs:x", "DifferentialController.inputs:linearVelocity"),

                ("wheel_names_array.outputs:array", "wheel_names_array_add.inputs:array"),
                 ("wheel_names_array_add.outputs:array", "ArticulationController.inputs:jointNames"),

            ],
            og.Controller.Keys.SET_VALUES: [
                ("Context.inputs:domain_id", ROS_DOMAIN_ID),

                ("ROS2SubscribeTwist.inputs:topicName", "cmd_vel"),

                ("ArticulationController.inputs:robotPath", f"{ROBOT_STAGE_PATH}/base_footprint"),
                ("ArticulationController.inputs:targetPrim", f"{ROBOT_STAGE_PATH}/base_footprint"),

                ("DifferentialController.inputs:wheelRadius", 0.0885),
                ("DifferentialController.inputs:wheelDistance", 0.46),
                ("DifferentialController.inputs:maxLinearSpeed", 0.6),
                ("DifferentialController.inputs:maxAngularSpeed", 0.6),

                ("wheel_names_array.inputs:arrayType", "token[]"),
                ("wheel_names_array.inputs:input0", "left_wheel_joint"),
                ("wheel_names_array_add.inputs:index", 1),
                ("wheel_names_array_add.inputs:value", "right_wheel_joint"),
            ],
        },
    )

Topic		Replies	Views
Is the Action Graph in Isaac Sim different depending on the version? Isaac Sim isaac-sim-v4-2-0	0	6	January 7, 2025
Omnigraph with ROS1 Bridge: Python Scripting Not Working Isaac Sim	0	276	January 8, 2024
Unable to set childFrameId value for ROS1PublishOdometry [Standalone-IsaacSim] Isaac Sim ros	2	346	July 3, 2024
Can't run ROS Navigation example with 2022.1 Isaac Sim ros	10	1397	April 5, 2024
How to connect Omnigraph variables (read/write nodes) using python API? Isaac Sim python , isaac-sim-v4-2-0	6	24	January 13, 2025
How to speed up the robot? Isaac Sim python	15	1444	July 13, 2022
Doubts on publishing sim_camera data via python standalone Isaac Sim	8	1395	December 15, 2023
ROS2 Humble Bridge Crash Isaac Sim	15	951	March 3, 2023
OmniGraph fails to connect certain nodes with the Python API Isaac Sim	3	34	September 11, 2024
ROS2_bridge-humble migration Isaac Sim isaacsim	8	979	September 12, 2023

Isaac Sim | OmniGraph | Python API - Make array

Create the node first

Set the input values for the created node

Related topics