ModuleNotFoundError: No module named 'omni.isaac.core' and ModuleNotFoundError: No module named 'omni.isaac'

I am experiencing multiple issues while setting up and running Omniverse Isaac Sim on my system. Below is a detailed summary of the problems and the steps I’ve already taken to troubleshoot:

System Information

  • OS: Ubuntu 22.04
  • Isaac Sim Version: 4.2.0
  • Python Version: Provided with Isaac Sim (python.sh)
  • Environment: Conda environment named isaaclab

Issues Encountered

  1. Missing python.sh Script
  • When running ./python.sh -m pip list, I receive the error:

bash: ./python.sh: No such file or directory


* I used the `find` command, but the `python.sh` file seems to be missing from the expected locations.
* **Empty Extensions Directory**
* The directory `/home/cesiro-nvidia/.local/share/ov/pkg/isaac-sim-4.2.0/kit/exts` is completely empty.
* I suspect the installation might be incomplete, as core extensions like `omni.isaac` are not available.
* **`ModuleNotFoundError` for `omni.isaac.core`**
* When trying to import modules in my script, such as:

from omni.isaac.core.utils.stage import add_reference_to_stage


I get the error:

ModuleNotFoundError: No module named ‘omni.isaac.core’


Steps Taken

    Verified the isaac-sim installation using find and ls commands.
    Reinstalled the package via the Omniverse Launcher (extensions still missing).
    Attempted to add directories to PYTHONPATH, including the root project directory and extensions directory.
    Activated the Conda environment (isaaclab) and ensured dependencies like omni-isaac-lab are installed.
    Searched for missing modules and extensions using:

find /home/cesiro-nvidia/.local/share/ov -name "omni*"

Manually tried enabling extensions in Python:

    from omni.isaac.core.utils.extensions import enable_extension
    enable_extension("omni.replicator.isaac")

    Tested the script using both the Conda environment and the Isaac Sim provided Python script (which is missing).

Logs and Observations

    The log file /home/cesiro-nvidia/.local/share/ov/pkg/isaac-sim-4.2.0/logs/kit.log does not indicate clear errors related to the missing extensions.
    Running Python scripts with the command:

/home/cesiro-nvidia/.local/share/ov/pkg/isaac-sim-4.2.0/kit/python.sh main.py

still results in ModuleNotFoundError.

Help Needed

    Why are the extensions missing from the installation, and how can I manually install or verify them?
    What is the proper method to configure PYTHONPATH and extensions for Isaac Sim in a custom Conda environment?
    How can I resolve the missing python.sh script, or is there an alternative way to access the Isaac Sim-specific Python interpreter?
    Are there additional steps to enable omni.replicator.isaac and other core extensions?

Any guidance or documentation links specific to these issues would be greatly appreciated!

I assume that you set up Isaac Lab correctly.

I thing there are misunderstandings here:

  1. Isaac Sim has its python, invoked by ./python.sh, and if you need to run Isaac Sim python script then go inside Isaac Sim path and use ./python.sh

  2. I assume you want to use Isaac Lab to do some RL, then after activating the isaaclab conda env you can simply use python <path_to_your_script> to run the code, or ./isaac_lab.sh -p <path_to_your_script>. In the end it still use Isaac Sim python but make sure that you follow the instructions in official documents.

Please find the file python.sh located at ~/.local/share/ov/pkg/isaac-sim-4.2.0/python.sh.

This is expected. Please refer to What is the location of Kit Extensions for Isaac Sim version 4.2.0.