OvPhysX Backend =============== .. warning:: OvPhysX is **highly experimental** and is not recommended for general use yet. The public surface is changing rapidly while the backend is under active development. Expect feature coverage and test commands to change between Isaac Lab 3.0 beta releases. .. warning:: Do not combine OvPhysX with the Kit visualizer. Commands such as ``physics=ovphysx --visualizer kit`` are unsupported because ovphysx loads USD-dependent PhysX plugins from its own package, while Kit already owns a separate USD/plugin stack in the same process. Use ``--visualizer newton``, ``--visualizer rerun``, ``--visualizer viser``, or omit ``--visualizer`` for headless execution. OvPhysX is a kit-less variant of the PhysX backend. It drives PhysX directly (without the Omniverse Kit runtime) and reads scene-level solver parameters from the USD ``PhysicsScene`` prim rather than from a Python config. The Python config :class:`~isaaclab_ov.physics.OvPhysxCfg` only exposes the handful of GPU buffer sizes that are not represented on the USD schema. OvPhysX is selected through :class:`~isaaclab_ov.physics.OvPhysxCfg`: .. code-block:: python from isaaclab.sim import SimulationCfg from isaaclab_ov.physics import OvPhysxCfg sim_cfg = SimulationCfg(physics=OvPhysxCfg()) Why use OvPhysX? ---------------- * **Kit-less execution.** OvPhysX avoids Omniverse Kit, which makes it a useful experimental path for headless deployments and for backends that don't need the Kit runtime stack. * **USD-as-source-of-truth.** Solver parameters are taken from the ``PhysicsScene`` USD prim, so authoring tools that already manage USD scenes do not need a parallel Python config. What works today ---------------- The asset and sensor surface tracks PhysX, but only a subset is implemented and validated at the time of writing. The following pieces are available on ``develop``: * RigidObject — merged via `PR #5426 `_. * Articulation — merged via `PR #5459 `_. * RigidObjectCollection — merged via `PR #5570 `_. * Contact Sensor — merged via `PR #5422 `_. * SceneDataProvider — merged via `PR #5589 `_. * FrameView — merged via `PR #5678 `_. * :class:`~isaaclab.assets.DeformableObject` — experimental volume- and surface-deformable support on CUDA simulation devices. Additional OvPhysX work remains in flight. IMU, Frame Transformer, Joint Wrench, PVA, Ray Caster, and rendering support are not documented as supported here until their implementations land on ``develop`` and pass the backend smoke tests. Deformable limitations ---------------------- OvPhysX deformables currently require every body matched by one :class:`~isaaclab.assets.DeformableObject` to have the same number of simulation nodes. Initialization raises an error for mixed node counts instead of exposing padded state that would produce incorrect reductions. Deformable scenes also require full-stage materialization. Startup cost therefore grows with the number of authored environments. Use this path for small validation scenes; training-scale workloads with thousands of environments are not currently supported. Installation ------------ The Isaac Lab source install includes the ``isaaclab_ov`` package, but it does not install the heavier ``ovphysx`` runtime wheel by default. After a standard source install, install the optional OvPhysX runtime dependency from the repository root: .. code-block:: bash ./isaaclab.sh -i 'ov[ovphysx]' You can also install all OV runtime wheels with: .. code-block:: bash ./isaaclab.sh -i 'ov[all]' The ``ov[ovphysx]`` selector installs the ``ovphysx`` runtime wheel declared by the root ``pyproject.toml`` ``ov`` extra. If the wheel is missing, OvPhysX-specific tests skip with ``ovphysx wheel not installed`` and user code fails at import time. Testing the Installation ------------------------ First check that the Python package and runtime wheel import correctly: .. tab-set:: .. tab-item:: uv (Recommended) .. code-block:: bash uv run python -c "import ovphysx.types; from isaaclab_ov.physics import OvPhysxCfg; print('OvPhysX runtime OK')" .. tab-item:: isaaclab.sh / isaaclab.bat .. code-block:: bash ./isaaclab.sh -p -c "import ovphysx.types; from isaaclab_ov.physics import OvPhysxCfg; print('OvPhysX runtime OK')" Then run a small backend smoke test: .. tab-set:: .. tab-item:: uv (Recommended) .. code-block:: bash uv run python -m pytest source/isaaclab_ov/test/assets/test_rigid_object.py::test_initialization -k cpu .. tab-item:: isaaclab.sh / isaaclab.bat .. code-block:: bash ./isaaclab.sh -p -m pytest source/isaaclab_ov/test/assets/test_rigid_object.py::test_initialization -k cpu To try a task that declares an OvPhysX physics preset, use the same preset CLI syntax as the other backends: .. tab-set:: .. tab-item:: uv (Recommended) .. code-block:: bash uv run isaaclab zero_agent --task Isaac-Cartpole-Direct \ --num_envs 128 --max_steps 64 --viz none physics=ovphysx .. tab-item:: isaaclab.sh / isaaclab.bat .. code-block:: bash ./isaaclab.sh -p scripts/environments/zero_agent.py --task Isaac-Cartpole-Direct \ --num_envs 128 --max_steps 64 --viz none physics=ovphysx This command runs a 64-step headless zero-action rollout and then exits. Supported locomotion environments --------------------------------- The following locomotion training environments declare an ``ovphysx`` physics preset. Their corresponding ``-Play`` variants support the same backend where available. * ``Isaac-Ant-Direct`` * ``Isaac-Humanoid-Direct`` * ``IsaacContrib-Velocity-Rough-AnymalB`` * ``IsaacContrib-Velocity-Rough-AnymalC`` * ``Isaac-Velocity-Flat-AnymalD`` * ``Isaac-Velocity-Rough-AnymalD`` * ``IsaacContrib-Velocity-Rough-UnitreeA1`` * ``IsaacContrib-Velocity-Rough-UnitreeGo1`` * ``Isaac-Velocity-Rough-UnitreeGo2`` * ``Isaac-Velocity-Rough-Cassie`` * ``Isaac-Velocity-Rough-G1`` * ``Isaac-Velocity-Rough-H1`` Status and follow-up -------------------- OvPhysX is still experimental, so the feature list above is intentionally conservative. Broader feature coverage and documentation parity are tracked in `issue #5634 `_. For architectural context, see :ref:`backend-architecture`. For raw ``TensorBinding`` access and :class:`~isaaclab_ov.sim.views.OvPhysxView`, see :doc:`/source/concepts/native-physics-api/ovphysx`.