Unable to create/Robots/Nova Carter with Sensors

[howar845]

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Isaac Sim Version

5.0.0

Operating System

Ubuntu 24.04.3
ROS jazzy

GPU Information

• Model: RTX5060ti
• Driver Version: 575.64.03

Topic Description

I want to call carter in the scene, but following the “create/Robots/Nova Carter with Sensors” step, an error message pops up directly.

(another issue: ROS 2 Navigation — Isaac Sim Documentation

I followed step 1 to load “ROS2 > Navigation >Nova Carter“, but Nova Carter did not appear in the scene.)

Error Messages

{2025-09-10T05:36:12Z [2,229,225ms] [Error] [omni.kit.commands.command] Failed to execute a command: CreateReferenceCommand.

File “/home/lab710/isaacsim/exts/isaacsim.gui.menu/isaacsim/gui/menu/create_menu.py”, line 207, in

“onclick_fn”: lambda *_: create_asset(

File “/home/lab710/isaacsim/exts/isaacsim.gui.menu/isaacsim/gui/menu/create_menu.py”, line 38, in create_asset

path_to = omni.kit.commands.execute(

File “/home/lab710/isaacsim/extscache/omni.kit.commands-1.4.10+8131b85d.lx64.r.cp311/omni/kit/commands/command.py”, line 463, in execute

result = omni.kit.undo.execute(command, name, kwargs)

[…skipped…]

File “/home/lab710/isaacsim/extscache/omni.kit.commands-1.4.10+8131b85d.lx64.r.cp311/omni/kit/undo/undo.py”, line 78, in execute

result = _execute(command, name, level, history_key)

^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^

File “/home/lab710/isaacsim/extscache/omni.kit.commands-1.4.10+8131b85d.lx64.r.cp311/omni/kit/undo/undo.py”, line 459, in _execute

raise error

File “/home/lab710/isaacsim/extscache/omni.kit.commands-1.4.10+8131b85d.lx64.r.cp311/omni/kit/undo/undo.py”, line 420, in _execute

result = command.do()

^^^^^^^^^^^^

File “/home/lab710/isaacsim/extscache/omni.usd-1.13.10+8131b85d.lx64.r.cp311/omni/usd/commands/usd_commands.py”, line 5339, in do

ref_stage = Usd.Stage.Open(asset_layer, anonymous_layer)

^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^

<class ‘pxr.Tf.ErrorException’>

Error in ‘operator()’ at line 2549 in file /builds/omniverse/usd-ci/USD/pxr/usd/pcp/primIndex.cpp : 'Failed verification: ’ arcNum < srcInfo.size() ‘’}

Screenshots or Videos

[Simplychenable]

@howar845 as another user, i can’t seem to reproduce this issue on my end. i am running 5.0.0 on Windows though it did take a few seconds to load the asset for the first time. could you elaborate on your system setup, for example, behind any sort of firewall or variable internet connection?

if it helps, you can bypass this step by simply drag and dropping the nova carter directly from the content browser through Isaac Sim > Robots > NVIDIA > NovaCarter > nova_carter.usd which i believe is the same asset from the Create menu:

[howar845]

I’ve tried the following three methods, and only the Nova Carter sensor appears, but the car body itself doesn’t. If I use the code to add a JetBot, the entire car doesn’t appear. However, it’s strange that adding a Franka or other objects works fine. I don’t feel like I’m unable to connect to the remote server either.

1. followed your steps “Isaac Sim > Robots > NVIDIA > NovaCarter > nova_carter.usd”

2. added it from Isaac Sim assets.

3. used the following code in Script Editor.

import numpy as np

from isaacsim.core.api import World

from isaacsim.core.prims import Articulation

from isaacsim.core.utils.stage import add_reference_to_stage, get_stage_units

from isaacsim.storage.native import get_assets_root_path

from isaacsim.robot.wheeled_robots.robots import WheeledRobot

world = World(stage_units_in_meters=1.0)

world.scene.add_default_ground_plane()



assets_root_path = get_assets_root_path()



# Add Franka

asset_path = assets_root_path + "/Isaac/Robots/FrankaRobotics/FrankaPanda/franka.usd"

add_reference_to_stage(usd_path=asset_path, prim_path="/World/Arm")  

arm = Articulation(prim_paths_expr="/World/Arm", name="my_arm")  



# Add Carter

asset_path = assets_root_path + "/Isaac/Robots/NVIDIA/NovaCarter/nova_carter.usd"

add_reference_to_stage(usd_path=asset_path, prim_path="/World/Car")

car = Articulation(prim_paths_expr="/World/Car", name="my_car")



# Add jetbot

jetbot_asset_path = assets_root_path + "/Isaac/Robots/NVIDIA/Jetbot/jetbot.usd"



robot = WheeledRobot(

    prim_path="/World/Fancy_Robot",

    name="fancy_robot",

    wheel_dof_names=["left_wheel_joint", "right_wheel_joint"],

    create_robot=True,

    usd_path=jetbot_asset_path,

)

world.scene.add(robot)

[howar845]

[howar845]

[howar845]

[howar845]

[howar845]

[howar845]

[howar845]

Error Messages (when run # Add Carter code in Script Editor)

2025-09-16T11:43:07Z [46,907ms] [Error] [omni.kit.app.plugin] [py stderr]: ErrorException: 
    Error in 'operator()' at line 2549 in file /builds/omniverse/usd-ci/USD/pxr/usd/pcp/primIndex.cpp : 'Failed verification: ' arcNum < srcInfo.size() ''

At:
  /home/lab710/isaacsim/exts/isaacsim.core.utils/isaacsim/core/utils/stage.py(356): add_reference_to_stage
  /tmp/carb.mLIvVl/script_1758022984.py(22): <module>
  /home/lab710/isaacsim/extscache/omni.kit.window.script_editor-2.0.1+8131b85d/omni/kit/window/script_editor/script_editor_widget.py(154): _execute_script_async
  /home/lab710/isaacsim/kit/python/lib/python3.11/asyncio/events.py(84): _run
  /home/lab710/isaacsim/kit/python/lib/python3.11/asyncio/base_events.py(1936): _run_once
  /home/lab710/isaacsim/kit/extscore/omni.kit.async_engine/omni/kit/async_engine/async_engine.py(228): run_once
  /home/lab710/isaacsim/kit/extscore/omni.kit.async_engine/omni/kit/async_engine/async_engine.py(296): <lambda>

[zhengwang]

Hi @howar845 I am not able to reproduce the issue even with your script.

Have you tried to open original file for nova carter and see if it loads properly?

[howar845]

When I select the Nova Carter from the Isaac Sim assets and choose ‘Open File,’ only the Nova Carter’s sensors appear.

In the end, I had to download the USD model directly from the official website to finally open a functional Nova Carter in Isaac Sim. I still don’t understand why the other methods I tried didn’t work to open a normal Nova Carter.

Download Isaac Sim — Isaac Sim Documentation

Isaac Sim Assets / Robots & Sensors

[howar845]

[howar845]

[Simplychenable]

i have not seen this before but surprised that it could happen. many parts are missing from this asset from the getgo based on your screenshot. so the issue isn’t the method you are using to bring the asset into your stage but rather what is preventing the assets from being downloaded completely. just to compare, below is what i am seeing on my end in nova_carter.usd:

i wonder what the cause is. would love to hear what the mods/devs’ insights are. could reinstalling Isaac Sim even help in this situation? the reason why i had asked initially about firewall/connection is because i suspected it might’ve cause issue accessing the aws but was only a speculation.

[howar845]

Something strange is happening: I can’t Load as Reference the Nova Carter asset from the Isaac Sim assets, but all other assets load just fine.

I tested this on another computer (RTX 5070 ti / Ubuntu 24.03 / Isaac Sim 5.0) and encountered the exact same issue.

2025-09-20T12:59:52Z [1,989,964ms] [Error] [omni.ui.python] ErrorException: 
    Error in 'operator()' at line 2549 in file /builds/omniverse/usd-ci/USD/pxr/usd/pcp/primIndex.cpp : 'Failed verification: ' arcNum < srcInfo.size() ''

At:
  /home/lab710/isaacsim/exts/isaacsim.asset.browser/isaacsim/asset/browser/prop_property_delegate.py(135): _build_variant_options
  /home/lab710/isaacsim/exts/isaacsim.asset.browser/isaacsim/asset/browser/prop_property_delegate.py(89): build_widgets
  /home/lab710/isaacsim/extscache/omni.kit.browser.folder.core-1.10.9/omni/kit/browser/folder/core/property/browser_property_view.py(65): show
  /home/lab710/isaacsim/extscache/omni.kit.browser.folder.core-1.10.9/omni/kit/browser/folder/core/property/tree_folder_browser_widget_ex.py(336): _on_detail_selection_changed
  /home/lab710/isaacsim/extscache/omni.kit.browser.core-2.3.13/omni/kit/browser/core/widgets/thumbnail_view.py(281): _on_click
  /home/lab710/isaacsim/extscache/omni.kit.browser.core-2.3.13/omni/kit/browser/core/widgets/thumbnail_view.py(245): _on_mouse_pressed
  /home/lab710/isaacsim/extscache/omni.kit.browser.core-2.3.13/omni/kit/browser/core/widgets/thumbnail_view.py(241): <lambda>

2025-09-20T13:00:18Z [2,016,345ms] [Warning] [omni.usd] Warning: in _ReportErrors at line 3172 of /builds/omniverse/usd-ci/USD/pxr/usd/usd/stage.cpp -- In </World/nova_carter_02>: Unresolved reference prim path @https://omniverse-content-production.s3-us-west-2.amazonaws.com/Assets/Isaac/5.0/Isaac/Robots/NVIDIA/NovaCarter/Variants/Configuration/nova_carter_merged_no_internals.usd@</nova_carter> introduced by @<expired>@</nova_carter> (recomposing stage on stage @anon:0x714cb00025b0:World0.usd@ <0x714cb000abb0>)

2025-09-20T13:00:18Z [2,016,347ms] [Error] [omni.ui.python] ErrorException: 
    Error in 'operator()' at line 2549 in file /builds/omniverse/usd-ci/USD/pxr/usd/pcp/primIndex.cpp : 'Failed verification: ' arcNum < srcInfo.size() ''

At:
  /home/lab710/isaacsim/exts/isaacsim.asset.browser/isaacsim/asset/browser/prop_property_delegate.py(191): load_as_reference
  /home/lab710/isaacsim/exts/isaacsim.asset.browser/isaacsim/asset/browser/prop_property_delegate.py(84): <lambda>

[howar845]

[Simplychenable]

to reiterate, this isn’t because you are using load as reference that’s the root of this issue. as you’ve already stated, it works on other robots. the main problem is the nova_carter.usd you are using from the Isaac Sim Assets browser is not 100% complete (as far as i can tell). in other words, no matter how you are loading the model, it will always have missing parts (the last screenshot i took showed a complete nova_carter.usd with no missing parts). unfortunately, i have not seen this issue before so i will have to defer to the mods to understand why this particular asset is showing up as incomplete on your end.

[Simplychenable]

here’s another way to confirm - if you navigate to Isaac Sim > Robots > NVIDIA > NovaCarter > Parts in the content browser, how many individual USDs are there? i counted 922 USD files in that folder on my end. some of the missing parts from your Isaac Sim Asset browser for nova carter are sourced from this folder (such as the tires). so if you do not have 922 files, then that would confirm that you do not have all the necessary pieces to have a complete nova carter robot.

however, if you do see 922 USDs in that folder, yet the nova carter robot is still missing parts, that could mean it’s a different type of problem.

[howar845]

I’m unsure how to count the total number of files, but I can search for chassis and wheel inside my Parts directory.

If your path is the same as mine, the number of files we have might be the same. My path is:https://omniverse-content-production.s3-us-west-2.amazonaws.com/Assets/Isaac/5.0/Isaac/Robots/NVIDIA/NovaCarter/Parts