RuntimeError on Episode End: "viewer_camera" is not a valid Usd.Prim or UsdGeom.Camera in Isaac Sim 4.1

[dongwxxkchoi]

Hello, AI45Lab.

First, thank you for your excellent work on this benchmark. I'm currently using your platform for my research and have encountered a persistent issue.

I have tried setting up the environment using both conda and docker, but the following error occurs consistently after the agent is done, regardless of whether the simulation is run in headless mode or not.

This behavior appears to be happening at the end of each episode, possibly during the scene or agent reset phase.

Any guidance on this would be greatly appreciated. Thank you for your time and support.

Steps to Reproduce

1. bash entrypoints/eval_test.sh
2. see error

Error Output

[agent] raw output:
```json
{
    "action": "DONE",
    "caution": null
}
[agent] next plan:
{'action': 'DONE', 'caution': None}
[executor] -> executing done()
Traceback (most recent call last):
  File "/isaac-sim/kit/exts/omni.kit.widget.viewport/omni/kit/widget/viewport/impl/texture.py", line 355, in on_drawable_changed
    self.__drawable_changed_fn(texture['rp_resource'], event.payload.get('presentation_key', 0))
  File "/isaac-sim/kit/exts/omni.kit.widget.viewport/omni/kit/widget/viewport/widget.py", line 464, in __set_image_data
    vp_api._sync_viewport_api(camera, canvas_size, vp_api.time, view, projection, force_update=True)
  File "/isaac-sim/kit/exts/omni.kit.widget.viewport/omni/kit/widget/viewport/api.py", line 544, in _sync_viewport_api
    self.__projection = self._conform_projection(policy, camera, image_aspect, canvas_aspect, projection)
  File "/isaac-sim/kit/exts/omni.kit.widget.viewport/omni/kit/widget/viewport/api.py", line 473, in _conform_projection
    gf_camera = camera.GetCamera(self.__time)
AttributeError: 'NoneType' object has no attribute 'GetCamera'
Traceback (most recent call last):
  File "/isaac-sim/extsPhysics/omni.physx.ui/omni/physxui/scripts/extension.py", line 82, in on_stage_update
    cam_pos = camera.position_world
  File "/isaac-sim/kit/exts/omni.kit.viewport.utility/omni/kit/viewport/utility/camera_state.py", line 100, in position_world
    return self.usd_camera.ComputeLocalToWorldTransform(self.__time).Transform(Gf.Vec3d(0, 0, 0))
  File "/isaac-sim/kit/exts/omni.kit.viewport.utility/omni/kit/viewport/utility/camera_state.py", line 87, in usd_camera
    raise RuntimeError(f'"{self.__camera_path}" is not a valid Usd.Prim or UsdGeom.Camera')
RuntimeError: "/World/viewer_camera" is not a valid Usd.Prim or UsdGeom.Camera

Environment

• Operating System: Ubuntu 20.04 LTS
• Omnigibson: v1.1.1
• Isaac Sim: NVIDIA Isaac Sim 4.1
• GPU: NVIDIA TITAN RTX
• GPU Driver Version NVIDIA Driver Version 570.18.1

[ursulalujun]

Thank you for your interest in IS-Bench.
This error is from Isaac. If the problem only occurs at the end of the program without affecting the execution of the task, it's safe to ignore it.

Here are some discussions on this issue in the Omnigibson simulator community:
StanfordVL/BEHAVIOR-1K#1074
StanfordVL/BEHAVIOR-1K#1203