Bump usd-core dependency to 26.05 to fix USD physics crash

isaaclab.bat

@@ -41,6 +41,13 @@ if exist "%ISAACLAB_PATH%\_isaac_sim\" (
     )
 )
 
+rem Prefer omni.usd.libs over usd-core for pxr imports to avoid TfType::AddAlias
+rem conflicts with ovrtx/ovphysx (see tools/setup_usd_libs.py for details).
+for /f "delims=" %%d in ('"%python_exe%" "%ISAACLAB_PATH%\tools\setup_usd_libs.py"') do (
+    set "PYTHONPATH=%%d;!PYTHONPATH!"
+    set "PATH=%%d\bin;!PATH!"
+)
+
 rem Execute CLI.
 "%python_exe%" -c "from isaaclab.cli import cli; cli()" %*
 

isaaclab.sh

@@ -61,5 +61,16 @@ if [ -d "$ISAACLAB_PATH/_isaac_sim" ]; then
     fi
 fi
 
+# Prefer omni.usd.libs over usd-core for pxr imports to avoid TfType::AddAlias
+# conflicts with ovrtx/ovphysx.  omni.usd.libs/pxr/ is a namespace package, so
+# Python ignores PYTHONPATH order and picks usd-core's regular pxr instead; writing
+# a minimal __init__.py promotes it to a regular package so path order takes effect.
+_ov_usd_libs_dir=$("$python_exe" "$ISAACLAB_PATH/tools/setup_usd_libs.py")
+if [ -n "$_ov_usd_libs_dir" ]; then
+    export PYTHONPATH="$_ov_usd_libs_dir:$PYTHONPATH"
+    export LD_LIBRARY_PATH="$_ov_usd_libs_dir/bin:$LD_LIBRARY_PATH"
+fi
+unset _ov_usd_libs_dir
+
 # Execute CLI.
 exec "$python_exe" -c "from isaaclab.cli import cli; cli()" "$@"

pyproject.toml

@@ -63,7 +63,7 @@ dependencies = [
     # OpenUSD (kit-less mode). Both packages vendor a complete ``pxr`` runtime, so
     # they must never co-install: usd-core supplies pxr where it has wheels (x86_64),
     # usd-exchange supplies it on aarch64 (where usd-core has no wheel).
-    "usd-core>=25.11,<26.0 ; platform_machine in 'x86_64 AMD64'",
+    "usd-core>=26.05,<27.0 ; platform_machine in 'x86_64 AMD64'",
     "usd-exchange>=2.2 ; platform_machine in 'aarch64 arm64'",
     # avoid broken hf-xet pre-release cached on NVIDIA Artifactory
     "hf-xet>=1.4.1,<2.0.0 ; platform_machine in 'x86_64 AMD64 aarch64 arm64'",
@@ -86,7 +86,7 @@ dependencies = [
     # exact git commit is forced via [tool.uv].override-dependencies (uv sync only).
     # The importers extra carries the mesh-processing deps (coacd, fast-simplification,
     # ...) that honoring USD-authored ``physics:approximation`` requires.
-    "newton[sim,importers]>=1.2.0",
+    "newton[sim]>=1.2.0",
     # Loose bound co-resolves with isaacsim's ==0.2.0; the override below forces >=0.4.0.
     "newton-usd-schemas>=0.2.0",
     "PyOpenGL-accelerate>=3.1.0",
@@ -340,6 +340,10 @@ override-dependencies = [
     "newton[sim,importers] @ git+https://github.com/newton-physics/newton.git@81cdcfc2dd89f8b7285e32b5e3853092a97fa6f9",
     # Force the Newton-matched schemas over isaacsim's ==0.2.0 pin.
     "newton-usd-schemas>=0.4.0",
+    # newton[importers] pins usd-core<26.5 in every published release and the current
+    # dev build; override it so uv accepts our usd-core>=26.05 requirement.
+    # Remove once newton publishes a release that drops the upper bound.
+    "usd-core>=26.05,<27.0 ; platform_machine in 'x86_64 AMD64'",
     "torch==2.11.0",
     "torchvision==0.26.0",
     "torchaudio==2.11.0",

source/isaaclab/changelog.d/mataylor-golden-sim-usd.minor.rst

@@ -0,0 +1,5 @@
+Changed
+^^^^^^^
+
+* Bumped ``usd-core`` dependency from ``>=25.11,<26.0`` to ``>=26.05,<27.0`` on x86_64 to resolve
+  a crash in ``libusd_ms`` triggered by USD physics loading (``LoadUsdPhysicsFromRange``) for kitless runs.

source/isaaclab/test/benchmark/test_capture.py

@@ -72,7 +72,7 @@ def test_capture_versions_preserves_runtime_packages():
         StringMetadata(name="ovphysx_version", data="3.0.5"),
         StringMetadata(name="mujoco_version", data="3.8.1"),
         StringMetadata(name="cuda_bindings_version", data="12.9.4"),
-        StringMetadata(name="usd_core_version", data="25.11"),
+        StringMetadata(name="usd_core_version", data="26.05"),
         StringMetadata(name="isaaclab_release_version", data="3.0.0"),
     ]
     bm = _Bm({"VersionInfo": _Rec(MeasurementData(measurements=[], metadata=md, artefacts=[]))})
@@ -89,7 +89,7 @@ def test_capture_versions_preserves_runtime_packages():
     assert versions.ovphysx == "3.0.5"
     assert versions.mujoco == "3.8.1"
     assert versions.cuda_bindings == "12.9.4"
-    assert versions.usd_core == "25.11"
+    assert versions.usd_core == "26.05"
     assert versions.isaaclab_release == "3.0.0"
 
 

source/isaaclab/test/cli/test_setup_usd_libs.py

@@ -0,0 +1,186 @@
+# Copyright (c) 2022-2026, The Isaac Lab Project Developers (https://github.com/isaac-sim/IsaacLab/blob/main/CONTRIBUTORS.md).
+# All rights reserved.
+#
+# SPDX-License-Identifier: BSD-3-Clause
+
+"""Tests for tools/setup_usd_libs.py.
+
+Covers two Isaac Sim install layouts:
+
+* **Symlink / binary install** — ``ISAACLAB_PATH/_isaac_sim/extscache/omni.usd.libs-<ver>/``
+* **Wheel / pip install** — ``isaacsim`` package on ``sys.path``; ``extscache`` lives next
+  to the package ``__init__.py``.
+
+Each test runs the script as a subprocess so the module-level code executes in a
+clean interpreter.
+"""
+
+from __future__ import annotations
+
+import os
+import sys
+from pathlib import Path
+
+import pytest
+
+pytestmark = pytest.mark.unit
+
+
+# ---------------------------------------------------------------------------
+# Helpers
+# ---------------------------------------------------------------------------
+
+
+def _script_path() -> Path:
+    for parent in Path(__file__).resolve().parents:
+        candidate = parent / "tools" / "setup_usd_libs.py"
+        if candidate.is_file():
+            return candidate
+    raise RuntimeError("Could not find tools/setup_usd_libs.py")
+
+
+def _run(env_overrides: dict[str, str], tmp_path: Path) -> tuple[int, str, str]:
+    """Run setup_usd_libs.py as a subprocess and return (returncode, stdout, stderr)."""
+    import subprocess
+
+    env = {**os.environ, **env_overrides}
+    result = subprocess.run(
+        [sys.executable, str(_script_path())],
+        capture_output=True,
+        text=True,
+        env=env,
+    )
+    return result.returncode, result.stdout, result.stderr
+
+
+def _make_usd_libs(base: Path, version: str = "26.05.0") -> Path:
+    """Create a minimal omni.usd.libs extension directory under *base*/extscache."""
+    usd_libs = base / "extscache" / f"omni.usd.libs-{version}"
+    (usd_libs / "pxr").mkdir(parents=True)
+    return usd_libs
+
+
+# ---------------------------------------------------------------------------
+# Symlink / binary install
+# ---------------------------------------------------------------------------
+
+
+class TestSymlinkInstall:
+    """ISAACLAB_PATH/_isaac_sim/extscache layout (binary / developer install)."""
+
+    def _isaaclab_env(self, tmp_path: Path) -> dict[str, str]:
+        return {"ISAACLAB_PATH": str(tmp_path), "PYTHONPATH": ""}
+
+    def test_prints_usd_libs_dir(self, tmp_path: Path) -> None:
+        """Script prints the usd_libs_dir path when omni.usd.libs exists."""
+        usd_libs = _make_usd_libs(tmp_path / "_isaac_sim")
+
+        rc, stdout, _ = _run(self._isaaclab_env(tmp_path), tmp_path)
+
+        assert rc == 0
+        assert stdout == str(usd_libs)
+
+    def test_creates_pxr_init_when_missing(self, tmp_path: Path) -> None:
+        """Script creates pxr/__init__.py so the directory becomes an importable package."""
+        usd_libs = _make_usd_libs(tmp_path / "_isaac_sim")
+
+        _run(self._isaaclab_env(tmp_path), tmp_path)
+
+        assert (usd_libs / "pxr" / "__init__.py").is_file()
+
+    def test_leaves_existing_pxr_init_intact(self, tmp_path: Path) -> None:
+        """Script does not overwrite an existing pxr/__init__.py."""
+        usd_libs = _make_usd_libs(tmp_path / "_isaac_sim")
+        init_py = usd_libs / "pxr" / "__init__.py"
+        init_py.write_text("# sentinel")
+
+        _run(self._isaaclab_env(tmp_path), tmp_path)
+
+        assert init_py.read_text() == "# sentinel"
+
+    def test_picks_latest_version(self, tmp_path: Path) -> None:
+        """Script selects the lexicographically last omni.usd.libs version."""
+        _make_usd_libs(tmp_path / "_isaac_sim", "25.11.0")
+        newer = _make_usd_libs(tmp_path / "_isaac_sim", "26.05.0")
+
+        _, stdout, _ = _run(self._isaaclab_env(tmp_path), tmp_path)
+
+        assert stdout == str(newer)
+
+    def test_no_usd_libs_produces_no_output(self, tmp_path: Path) -> None:
+        """Script exits 0 with no stdout when extscache has no omni.usd.libs dirs."""
+        (tmp_path / "_isaac_sim" / "extscache").mkdir(parents=True)
+
+        rc, stdout, _ = _run(self._isaaclab_env(tmp_path), tmp_path)
+
+        assert rc == 0
+        assert stdout == ""
+
+    @pytest.mark.skipif(sys.platform == "win32", reason="chmod semantics differ on Windows")
+    def test_readonly_pxr_dir_warns_and_exits_cleanly(self, tmp_path: Path) -> None:
+        """Script emits [WARNING] to stderr and exits 0 when pxr/ is not writable."""
+        usd_libs = _make_usd_libs(tmp_path / "_isaac_sim")
+        pxr_dir = usd_libs / "pxr"
+        pxr_dir.chmod(0o555)
+
+        try:
+            rc, _, stderr = _run(self._isaaclab_env(tmp_path), tmp_path)
+        finally:
+            pxr_dir.chmod(0o755)
+
+        assert rc == 0
+        assert "[WARNING]" in stderr
+
+
+# ---------------------------------------------------------------------------
+# Wheel / pip install
+# ---------------------------------------------------------------------------
+
+
+class TestWheelInstall:
+    """Wheel install layout: isaacsim on sys.path, extscache next to __init__.py."""
+
+    def _wheel_env(self, isaacsim_site: Path) -> dict[str, str]:
+        """Environment that hides the symlink path and exposes a fake isaacsim package."""
+        existing = os.environ.get("PYTHONPATH", "")
+        pythonpath = str(isaacsim_site) + (os.pathsep + existing if existing else "")
+        return {
+            "ISAACLAB_PATH": "",  # no _isaac_sim symlink
+            "PYTHONPATH": pythonpath,
+        }
+
+    def _make_fake_isaacsim(self, base: Path, version: str = "26.05.0") -> Path:
+        """Create a minimal fake isaacsim package with an extscache directory."""
+        pkg = base / "isaacsim"
+        pkg.mkdir(parents=True, exist_ok=True)
+        (pkg / "__init__.py").write_text("")
+        return _make_usd_libs(pkg, version)
+
+    def test_prints_usd_libs_dir(self, tmp_path: Path) -> None:
+        """Script finds omni.usd.libs via importlib.util.find_spec when no symlink exists."""
+        usd_libs = self._make_fake_isaacsim(tmp_path)
+
+        rc, stdout, _ = _run(self._wheel_env(tmp_path), tmp_path)
+
+        assert rc == 0
+        assert stdout == str(usd_libs)
+
+    def test_creates_pxr_init_when_missing(self, tmp_path: Path) -> None:
+        """Script promotes pxr/ to a package in the wheel-install layout too."""
+        usd_libs = self._make_fake_isaacsim(tmp_path)
+
+        _run(self._wheel_env(tmp_path), tmp_path)
+
+        assert (usd_libs / "pxr" / "__init__.py").is_file()
+
+    def test_picks_latest_version(self, tmp_path: Path) -> None:
+        """Script selects the latest omni.usd.libs in the wheel extscache."""
+        pkg = tmp_path / "isaacsim"
+        pkg.mkdir(parents=True)
+        (pkg / "__init__.py").write_text("")
+        _make_usd_libs(pkg, "25.11.0")
+        newer = _make_usd_libs(pkg, "26.05.0")
+
+        _, stdout, _ = _run(self._wheel_env(tmp_path), tmp_path)
+
+        assert stdout == str(newer)

source/isaaclab/test/cli/test_source_package_metadata.py

@@ -23,18 +23,6 @@ def _repo_root() -> Path:
     raise RuntimeError("Could not find Isaac Lab repository root.")
 
 
-def test_isaaclab_usd_core_pin_stays_on_isaacsim_compatible_usd25_abi():
-    """The kit-less USD package must stay on the Isaac Sim compatible USD 25 ABI."""
-    with (_repo_root() / "pyproject.toml").open("rb") as f:
-        pyproject = tomllib.load(f)
-
-    usd_core_dependencies = [
-        dependency for dependency in pyproject["project"]["dependencies"] if dependency.startswith("usd-core")
-    ]
-
-    assert usd_core_dependencies == ["usd-core>=25.11,<26.0 ; platform_machine in 'x86_64 AMD64'"]
-
-
 def test_isaaclab_standalone_usd_providers_are_platform_disjoint():
     """Standalone USD packages must not overlap on platforms where both ship ``pxr``."""
     with (_repo_root() / "pyproject.toml").open("rb") as f:

source/isaaclab/test/cli/test_uv_run_pyproject.py

@@ -153,7 +153,7 @@ def test_uv_run_base_dependencies_cover_newton_rsl_rl_training():
     # Newton is the default physics engine and RSL-RL the default training library,
     # so both ship as core third-party requirements (not opt-in extras). The importers
     # extra carries the mesh-processing deps that authored collision approximations need.
-    assert any(dep.startswith("newton[sim,importers]") for dep in dependencies)
+    assert any(dep.startswith("newton[sim]") for dep in dependencies)
     assert any(dep.startswith("rsl-rl-lib") for dep in dependencies)
 
 

tools/setup_usd_libs.py

@@ -0,0 +1,52 @@
+# Copyright (c) 2022-2026, The Isaac Lab Project Developers (https://github.com/isaac-sim/IsaacLab/blob/main/CONTRIBUTORS.md).
+# All rights reserved.
+#
+# SPDX-License-Identifier: BSD-3-Clause
+
+"""Locate omni.usd.libs and promote its pxr package to a regular package.
+
+Prints the extension directory to stdout on success, nothing on failure.
+Called by isaaclab.sh / isaaclab.bat to populate PYTHONPATH / LD_LIBRARY_PATH.
+"""
+
+import glob
+import importlib.util
+import os
+import sys
+
+
+def _find_extscache() -> str:
+    # Binary / symlink install: ISAACLAB_PATH/_isaac_sim/extscache.
+    # Only probe when ISAACLAB_PATH is set; an empty value would produce a
+    # relative path that resolves against CWD and may accidentally match a
+    # _isaac_sim symlink in an unrelated working directory.
+    isaaclab_path = os.environ.get("ISAACLAB_PATH", "")
+    if isaaclab_path:
+        symlink_path = os.path.join(isaaclab_path, "_isaac_sim", "extscache")
+        if os.path.isdir(symlink_path):
+            return symlink_path
+
+    # Wheel / pip install: locate the isaacsim package without importing it so
+    # that this script can run before PYTHONPATH is fully configured.
+    spec = importlib.util.find_spec("isaacsim")
+    if spec is not None and spec.origin:
+        return os.path.join(os.path.dirname(spec.origin), "extscache")
+
+    return ""
+
+
+extscache = _find_extscache()
+candidates = sorted(glob.glob(os.path.join(extscache, "omni.usd.libs-*"))) if extscache else []
+if candidates:
+    usd_libs_dir = candidates[-1]
+    init_py = os.path.join(usd_libs_dir, "pxr", "__init__.py")
+    if os.path.exists(os.path.join(usd_libs_dir, "pxr")) and not os.path.isfile(init_py):
+        try:
+            open(init_py, "w").close()
+        except OSError as exc:
+            print(
+                f"[WARNING] Cannot promote omni.usd.libs/pxr to a regular package; skipping USD path setup: {exc}",
+                file=sys.stderr,
+            )
+            sys.exit(0)
+    print(usd_libs_dir, end="")