Known Issues

General

The grid in the viewport is drawn as an overlay ontop of the scene geometry and does not clip through it.

If running Omniverse Isaac Sim headless connected via the remote client and you exit on shutdown the following error can occur, it can be ignored:

[ext: omni.physx] shutdown
Fatal Python error: Segmentation fault

Thread 0x00007f46f8faa740 (most recent call first):
File "..._build/target-deps/kit_sdk_release/_build/linux-x86_64/release/extsPhysics/omni.physx/omni/physx/scripts/extension.py", line 30 in on_shutdown
File "..._build/target-deps/kit_sdk_release/_build/linux-x86_64/release/plugins/bindings-python/omni/ext/impl/_internal.py", line 225 in shutdown_all
File "..._build/target-deps/kit_sdk_release/_build/linux-x86_64/release/plugins/bindings-python/omni/ext/impl/_internal.py", line 261 in shutdown_all_extensions
File "..._build/target-deps/kit_sdk_release/_build/linux-x86_64/release", line 3 in <module>

When running in windowed container, the following errors may be ignored and the app will continue to run after waiting for awhile:

ERROR: Could not find a version that satisfies the requirement psutil (from versions: none)
ERROR: No matching distribution found for psutil
WARNING: Retrying (Retry(total=4, connect=None, read=None, redirect=None, status=None)) after connection broken by 'NewConnectionError('<pip._vendor.urllib3.connection.VerifiedHTTPSConnection object at 0x7fcdcc284dd8>: Failed to establish a new connection: [Errno -3] Temporary failure in name resolution',)': /simple/psutil/``

If exiting standalone python scripts with Ctrl-C, it may need to be done twice to exit.
If Nucleus is not working on Docker, see Manually Installing Nucleus in a Container
If more than one asset in URDF contains the same material name, only one material will be created, regardless if the parameters in the material are different (e.g two meshes have materials with the name “material”, one is blue and the other is red. both meshes will be either red or blue.). This also applies for textured materials.
MJCF importer does not show the built-in bookmark in the file picker dialog. The bookmark is still available in the content pane and can be copy-pasted into the file picker dialog.
If you see a black screen when running on Windows, use the --vulkan command-line argument during startup
Debug Visualizations are not present in fisheye lens cameras that are not pinhole because that feature is not implemented.
Assigning a viewport resolution that exceeds the available VRAM will result in the application throwing ERROR_OUT_OF_DEVICE_MEMORY errors. Subsequently, reducing the resolution to a smaller value may lead to a crash.
When using World or SimulationContext from omni.isaac.core with OmniGraph, make sure the graphs are created before the World or SimulationContext are initialized.
Using replicator’s rep.new_layer() functionality, which creates a new layer in which to place and randomize assets, may lead to issues in simulation scenarios where these assets are used. In such cases the use of rep.new_layer() can be omitted.
When running through python, selecting physics objects and then another object on screen may result in one or more omni.kit.manupulator errors. This error is non-detrimental to the code execution and may be safely ignored.
Dragging and dropping an asset with default values in OmniGraph nodes should be saved with scene and reloaded before hitting Play to make sure all values are correctly set.

Error on exiting ./isaac-sim.headless.native.sh from UI.

[Error] [carb.livestream.plugin] nvstPushStreamData timeout for eye 0, stream (nil).

Quadruped Robot is not able to move backward with NUM 2 or Down Arrow keys.
Cortex samples with ROS synchronization may perform abnormaly and not be able to execute the task if the running FPS drops below 25 FPS.
If randomized materials are not loaded on time for synthetic data generation the rt_subframes should be set to be at least 2.
Some grippers with parallel mechanism (i.e. Robotiq 2F-85 and 2F-C2) have links that do not move with rest of the gripper.
Multiple Robot ROS2 Navigation tutorial has high CPU usage. If you observe instances of robots colliding or experiencing localization issues, it’s likely because the Nav2 stack is unable to properly synchronize with sensor data, resulting in missed controller commands.
There can be many warnings and other messages when running Isaac Sim. The amount of log output can be reduced by using the following command line arguments
--/log/level=error --/log/fileLogLevel=error --/log/outputStreamLevel=error
Using Replicator to write to S3 buckets with the built-in backend in Windows may require setting the credentials in the environment variables instead of the aws config files. This is because of a possible path parsing error in boto3 on Windows.
XR extensions do not work properly on windows
When running standalone examples in windows, in some scenarios threads may not be properly cleaned up when the application is closed. This can usually be ignored as the application will still succesfully close. As a workaround, you can add multiple standalone_app.update() calls before calling standalone_app.close().
Windows fatal exception: access violation Thread 0x00000634 (most recent call first):

Warnings

Warnings similar to the following can be ignored:
- [Warning] [omni.usd] Warning (secondary thread)
- [Warning] [carb.tasking.plugin] Counter 0x7f25e002f8d0
- [Warning] [rtx.neuraylib.plugin] [MDLC:COMPILER] 1.0 MDLC comp warn
- [Warning] [rtx.mdltranslator.plugin] Unable to resolve
- [Warning] [omni.tagging.plugin] Failed to discover tagging service
- [Warning] [omni.isaac.dynamic_control.plugin] DcFindArticulationDof: Function called while not simulating
- [Warning] [omni.isaac.dynamic_control.plugin] DcSetDofProperties: Function called while not simulating
- [Warning] [omni.client.plugin] Tick: authentication: Could not connect to discovery service at "wss://...
If Physics is not needed this message can be ignored:
- [Warning] [omni.physx.plugin] Physics USD: Physics scene not found. A temporary default PhysicsScene prim was added automatically!
If there is unwanted noise in simulated depth images, disable anti-aliasing under the Render Settings ->Ray Tracing -> Anti-Aliasing tab by setting the Algorithm to None

Pyperclip is used to copy text in some extensions, if you see the following message please refer to the link to install a supported copy/paste mechanism

Pyperclip could not find a copy/paste mechanism for your system.
For more information, please visit https://pyperclip.readthedocs.io/en/latest/index.html#not-implemented-error

If the parent prim of a joint does not correspond to body 0 then the value returned from physX will be the negation of the USD value.
If you see the following UI warning, followed by a call stack, it can be ignored:
- [Warning] [omni.ui] Container::addChild attempting to add a child during a draw callback

If you see warnings similar to the following when running ROS2 sample assets, they can be ignored:

[Warning] [omni.graph.core.plugin] /iw_hub/front_hawk/left_camera_publish_camera_info: [/iw_hub/front_hawk] OmniGraph Warning: OgnROS2CameraHelper:sensor_type == camera_info is deprecated as of Isaac Sim 4.1.0 in favour of OgnROS2CameraInfoHelper.
           (from compute() at line 208 in /home/horde/workspaces/omni_isaac_sim/_build/linux-x86_64/release/exts/omni.isaac.ros2_bridge/omni/isaac/ros2_bridge/ogn/python/nodes/OgnROS2CameraHelper.py)

Errors

Errors similar to the following can be ignored when running headless:

[Error] [carb.windowing-glfw.plugin] GLFW initialization failed.

[Error] [carb] Failed to startup plugin carb.windowing-glfw.plugin (interfaces: [carb::windowing::IGLContext v1.0],[carb::windowing::IWindowing v1.2]) (impl: carb.windowing-glfw.plugin)

[Error] [carb.scripting-python.plugin] RuntimeError: Failed to acquire interface: carb::windowing::IWindowing (pluginName: nullptr)

At:
/isaac-sim/kit/exts/omni.kit.window.cursor/omni/kit/window/cursor/cursor.py(27): on_startup
/isaac-sim/kit/plugins/bindings-python/omni/ext/impl/_internal.py(141): _startup_ext
/isaac-sim/kit/plugins/bindings-python/omni/ext/impl/_internal.py(174): startup_all_extensions_in_module
/isaac-sim/kit/plugins/bindings-python/omni/ext/impl/_internal.py(225): startup_all_extensions_in_module
PythonExtension.cpp::startup()(2): <module>

[Error] [omni.ext.plugin] [ext: omni.kit.window.cursor-1.0.1] Failed to process python module extension in '/isaac-sim/kit/exts/omni.kit.window.cursor/.'.

These errors can be ignored while running the running Kit Remote Client, if the client works as normal:

ERROR [BifrostClient: Streamer] {2B436200} -  updateVideoSettingsForNVbProfile: profile 8 is not handled
ERROR [NVST:ClientSession] {1E8D2700} -  Number of channels(2) is not valid for surround configuration
ERROR [NVST:ClientSession] {1E8D2700} -  Either in stereo or error in receiving opus information from server

ERROR [LAVCDecoder] {FC4A0700} - GERONIMO_ERROR 0xC0040006 GERONIMO_LAVCDECODER_DECODE: Packet decode failure.
ERROR [GIOInterface] {DAFFD700} - GERONIMO_ERROR 0xC0020003 GERONIMO_IOINTERFACE_INVALID_AUDIO_FUNC: Audio Renderer is NULL.
ERROR [NVST:ClientLibraryWrapper] {1E8D2700} -  Cannot find streamEventRaised for stream.media type 1
ERROR [NVST:ClientLibraryWrapper] {1E8D2700} -  Cannot find streamEventRaised for stream.media type 2

ERROR [NVST:RtspSessionPocoBase] {FB280700} -  perform() failed: 0
ERROR [NVST:RtspPocoEvent] {FB280700} -  RTSP-XNvEvent Polling failed: 0, rc: 408

ERROR [NVST:UdpRtpSource] {F9A7D700} -  UDP RTP Source: failed to receive data (Error: 0x80000013)
ERROR [NVST:RtpSourceQueue] {F9A7D700} -  RtpSourceQueue: failed to read RTP packet (Result: 0X80000013)
ERROR [BifrostClient: NvscWrapper] {1D0CF700} - Received old frame - current 7536 received 0
ERROR [BifrostClient: Interface] {2B436200} - nvbSendInputEvent(). SessionIdentifier is ''

Error similar to the following happens when STOPPING and STARTING simualtion again when using Isaac core world class. To stop the error trail, Reset the scene with one of the world.reset methods (in the core samples, this happen when pressing the RESET button on the UI).
2021-06-01 19:16:51 [65,842ms] [Error] [omni.kit.app._impl] [py stderr]: AttributeError: 'NoneType' object has no attribute '<...>' At: <...>
If you see this error “Could not find registered CUDA function ‘updateBodyExternalVelocitiesLaunch”, please add import omni.physx before all of your import torch:
import omni.physx import torch

Errors related to carb.flatcache and omni.graph when opening an asset can be ignored

[Error] [carb.flatcache.plugin] Error: UsdRelationship Foo.inputs:targetPrims has multiple targets, which is not supported
[Error] [carb.flatcache.plugin] Error: Foo/make_array.__resolved_outputs:array UsdRelationship not supported in GetPrimArrayAttr
[Error] [omni.graph] Tried to set a value on AttributeData 'inputs:Foo' of type 'token' with incompatible data (Unable to cast Python instance to C++ type (compile in debug mode for details))
[Error] [omni.graph] AttributeError: Attempted to get array size of non-array attribute inputs:Foo

If an asset contains an Action Graph and the Action Graph window is closed before re-opening the same asset, the following errors may appear and can be ignored:

[Error] [omni.usd] TF_PYTHON_EXCEPTION (secondary thread): in TfPyConvertPythonExceptionToTfErrors at line 114 of /buildAgent/work/ca6c508eae419cf8/USD/pxr/base/tf/pyError.cpp -- Tf Python Exception

[Error] [omni.kit.app.impl] [py stderr]: sys:1: RuntimeWarning: coroutine 'OmniGraphModel.__delayed_prim_changed' was never awaited
RuntimeWarning: Enable tracemalloc to get the object allocation traceback

[Error] [omni.graph] Invalid GraphObj object in Py_Graph in getNode

Errors when converting ShapeNet models may appear from the ‘omni.kit.asset_converter’ extension when textures for the target model are missing from the input dataset. These errors can be ignored.
[Error] [omni.kit.asset_converter.impl.omni_client_wrapper] Cannot copy from */images/texture2.jpg to */textures/texture2.jpg, error code: Result.ERROR_NOT_FOUND.

Errors when livestreaming. These errors can be ignored.

[Error] [carb.livestream.plugin] nvstPushStreamData timeout for eye 0, stream (nil).

Errors when using a jupyter notebook. These errors can be ignored.

[Error] [omni.kit.app.plugin] Can`t delay app ready event, it was already sent. Requester name: omni.usd

Errors while generating samples with flying_things_4d.yaml for larger value of ‘–num-scenes’ (specially when running for stress test)

[Error] [omni.physicsschema.plugin] Rigid Body of (/Replicator/SampledAssets/Population_9658d6d1/Ref_Xform_05/Ref) missing xformstack reset when child of rigid body (/Replicator/SampledAssets/Population_9658d6d1/Ref_Xform_05) in hierarchy. Simulation of multiple RigidBodyAPIs in a hierarchy will cause unpredicted results. Please fix the hierarchy or use XformStack reset.

Error like this when running Composer can be ignored.

[Error] [omni.graph.core.plugin] /Replicator/SDGPipeline/OgnSampleCombine_03: [/Replicator/SDGPipeline] Assertion raised in compute - AttributeData 'OgnSampleCombine_03.outputs:samples' of type 'float3[]' required array of elements of length 3, got array with elements of size 1

When Using the surface gripper between two objects that contain articulation root, the following error may appear and the surface Gripper won’t work. To avoid it, disable the Articulation API from the picked object.
[Error] [omni.physx.plugin] PhysX error: PxD6JointCreate: actors must be different

Error regarding omni.sensors plugin when starting Isaac Sim on Windows. This error can be ignored.

[Error] [carb] [Plugin: omni.sensors.nv.lidar.ext.plugin] Dependency: [omni::sensors::lidar::IGenericModelOutputIOFactory v0.1] failed to be resolved.

Hang

The WebRTC Client on Firefox may appear to hang after a few seconds when clicking the Play button. Using the Google Chrome or Chromium browser is recommended.
Isaac Sim may hang if a browser pop-up for logging into Nucleus is closed before completing the login. Force restart of Isaac Sim is required.
Isaac Sim may hang if it is shutdown from the File -> Exit Fast (Experimental) menu when using livestreaming. Please force close Isaac Sim and the livestream client when this happens.
The Omniverse Streaming Client may hang after Isaac Sim exits with the File -> Exit menu. Please force close the Omniverse Streaming Client when this happens.

Crash

Using RTX Lidar and a physics scene with GPU Dynamics enabled can lead to a crash in some cases. Please disable GPU dynamics in the physics scene and set the broadphase type to MBP if you encounter this issue
Docking windows in the isaac-sim UI when an RTX Lidars simulation is running will likely lead to a crash. Please pause the simulation before re-docking the window.
Shutting down the physics.tensors extension before the Python garbage collector cleans up the related objects can lead to a crash. To prevent this, please manually set the related tensor API objects in Python to None before unloading the extension.