Issues deploying pretrained policies in Isaac Sim

Omniverse Isaac Sim
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I am working with Isaac Sim / Lab and encountered some difficulties when deploying pretrained reinforcement learning policies.

Context:

  • My policies are trained in Isaac Lab using default PPO algorithm and SKRL framework (training script path is: IsaacLab\source\isaaclab_tasks\isaaclab_tasks\manager_based\locomotion\velocity\velocity_env_cfg.py

  • For deployment, I use a customized version of the example script: isaacsim\exts\isaacsim.robot.policy.examples\isaacsim\robot\policy\examples\robots\h1\H1FlatTerrainPolicy

Problems:

  • Weights format mismatch:

    • Isaac Lab saves weights .pt file as Python dictionary (dict with policy, value, and optimizer keys)

    • Isaac Sim’s policy loader expects a torch.jit._script.RecursiveScriptModule object to be loaded with torch.jit.load

    • Attempting torch.jit.load leads to errors like:

      RuntimeError: PytorchStreamReader failed locating file constants.pkl: file not found

  • Observation vector ambiguity**:**

    • The _compute_observation function must manually define the observation vector

    • However, in Isaac Lab manager-based training setup, the observation vector is abstracted away, making it unclear what the exact observation length / structure is.

Questions:

  • Is there an official or recommended workflow to convert SKRL-trained policies into TorchScript modules (torch.jit._script) compatible with Isaac Sim?

  • How can we extract the exact observation vector structure (dimension and components) from an Isaac Lab manager-based setup to ensure _compute_observation matches deployment requirements?

All in all, should we expect Isaac Lab’s pretrained policies (from SKRL or RSL-RL) to be deployable out-of-the-box in Isaac Sim, or is manual conversion always required?

Since, I am adapting the official example scripts rather than building from scratch, I assumed deployment would be seamless. Therefore, any guidance on the intended workflow would be greatly appreciated.

Isaac Sim Version

5.0.0

Operating System

Windows 10

GPU Information

  • Model: GeForce RTX 5070
  • Driver Version: 577.00
  • CUDA Version: 12.9
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We appreciate your understanding and look forward to assisting you.