Objects visible through simulation cameras but missing from WebRTC perspectiveviewport in Isaac Sim 6.0.1 / Isaac Lab

Omniverse Isaac Sim
1

Isaac Sim Version

Isaac Sim 6.0.1
Isaac Lab current/develop (3.0 stack)
Kit 110.1.2

Operating System

Ubuntu 24.04

GPU Information

  • Model: NVIDIA GeForce RTX 5090
  • Driver: 595.71.05
  • Graphics API: Vulkan
  • Python: 3.12
  • Installation: Conda/pip host installation, not Docker

Detailed Description

I am running an Isaac Lab environment through Isaac Sim WebRTC. The simulated
scene contains an SO-101 robot, table, vials, rack, wrist camera, and external
camera.

The scene objects are rendered correctly in the wrist and external camera
sensor views. However, when I switch the WebRTC viewport to the normal
Perspective camera, some or all scene objects are not visible.

Because the objects appear in the camera sensor outputs, they exist in the USD
scene and their geometry and poses appear valid. The problem seems specific to
the interactive Perspective viewport, Hydra scene synchronization, scene
partitioning, or geometry streaming.

The Kit log contains this warning:

[rtx.hydra] RenderDelegate : Warning
/rtx/hydra/readTransformsFromFabricInRenderDelegate and geometry streaming
are enabled together but this can cause issues with dynamic objects not
streaming correctly due to problems in the transform update.

Isaac Lab also enabled multi-GPU rendering by default, even though the
workstation contains one RTX 5090:

--/renderer/multiGpu/enabled=True

Expected Behavior

The Perspective viewport should display the same scene geometry that is
visible through the simulated camera sensors.

Actual Behavior

The simulated cameras render the objects correctly, but the WebRTC Perspective
viewport does not show them.

Error Messages

There is no fatal rendering error, but the following warning appears:

/rtx/hydra/readTransformsFromFabricInRenderDelegate and geometry streaming
are enabled together but this can cause issues with dynamic objects not
streaming correctly due to problems in the transform update.

There is also a Fabric version warning:

Possible version incompatibility. Attempting to load
omni::fabric::IStageReaderWriter with version v0.16 against v0.14.

What I’ve Tried

  • Updated to NVIDIA driver 595.71.05.
  • Confirmed the machine has only one RTX 5090.
  • Disabled multi-GPU rendering:

--/renderer/multiGpu/enabled=false

  • Confirmed that the objects are present and render correctly through the
    simulated wrist and external cameras.

  • Confirmed that the issue is specifically associated with the Perspective/
    WebRTC viewport.

  • Verified that the environment runs normally without a Python exception.

Related Issue

This appears potentially related to:

Additional Context

The environment is based on NVIDIA’s Sim-to-Real-SO-101-Workshop, ported from
an older Isaac Sim/Isaac Lab release to Isaac Sim 6.0.1. The Isaac Lab
installation itself was not modified.

The discrepancy between the camera sensor render products and the Perspective
viewport suggests that this is likely a viewport/Hydra/Fabric synchronization
or scene-partition visibility issue, rather than missing USD assets.

3

Hi, can you launch Isaac Sim with following option to see if the issue is caused by the warning you’re seeing?
--/rtx/hydra/readTransformsFromFabricInRenderDelegate=0

Let us know if you still see the warning with this, and share the full log if possible.

4

Hi, thank you for the suggestion.

I launched the environment with:

--/rtx/hydra/readTransformsFromFabricInRenderDelegate=0

I also disabled multi-GPU rendering:

--/renderer/multiGpu/enabled=false

I confirmed from the Kit log that both settings were passed correctly. The
previous warning about readTransformsFromFabricInRenderDelegate and geometry
streaming has disappeared.

Unfortunately, the original issue remains. The objects are visible when
viewing through the simulated wrist and external cameras, but they disappear
or are not visible when I switch to the Perspective viewport.

I have attached the complete Kit log. Please let me know if there are any
additional renderer, scene-partitioning, or viewport settings you would like
me to test.

kit_20260904_225642.log (1.2 MB)

5

Hi, thanks for running those tests, and for the log — that rules out the Fabric transform warning and multi-GPU.
Seems this is related to Isaac Lab’s per-environment RTX scene partitioning, which you correctly suspected.

Please try relaunching with this environment variable set:

export ISAAC_LAB_ENABLE_ISAAC_RTX_PER_ENV_SCENE_PARTITION=0

And let us know if you still have the issue.

6

Hi, We hope the above solution fixed your problem! I am closing the issue for now.