Fixes for stage in memory and Isaac Sim 4.5 compatibility (#503)

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- Adds 4.5 backwards compatibility (thanks @ooctipus)
- Adds unit test coverage for stage in mem for all envs
- Fixes an issue caused by a missing on play callback when stage in mem
is enabled (thanks @ossamaAhmed)
- Add stage in mem support for callbacks which require the stage in mem
(in headless mode)
- Add more clean-up steps to envs to avoid hanging issue with stage in
mem
- Fixes attach stage to context fn to include attaching to physx
- Sets stage in mem to False by default
- Cleans up warning messages

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- Bug fix (non-breaking change which fixes an issue)
- New feature (non-breaking change which adds functionality)
- Breaking change (fix or feature that would cause existing
functionality to not work as expected)
- This change requires a documentation update

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- [ ] I have made corresponding changes to the documentation
- [ ] My changes generate no new warnings
- [ ] I have added tests that prove my fix is effective or that my
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- [ ] I have updated the changelog and the corresponding version in the
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---------
Signed-off-by: rwiltz <165190220+rwiltz@users.noreply.github.com>
Signed-off-by: Kelly Guo <kellyguo123@hotmail.com>
Signed-off-by: Ashwin Varghese Kuruttukulam <123109010+ashwinvkNV@users.noreply.github.com>
Signed-off-by: Kelly Guo <kellyg@nvidia.com>
Signed-off-by: Michael Gussert <michael@gussert.com>
Signed-off-by: samibouziri <79418773+samibouziri@users.noreply.github.com>
Signed-off-by: Mayank Mittal <12863862+Mayankm96@users.noreply.github.com>
Signed-off-by: Kyle Morgenstein <34984693+KyleM73@users.noreply.github.com>
Signed-off-by: Hongyu Li <lihongyu0807@icloud.com>
Signed-off-by: Toni-SM <toni.semu@gmail.com>
Signed-off-by: James Tigue <166445701+jtigue-bdai@users.noreply.github.com>
Signed-off-by: Pascal Roth <57946385+pascal-roth@users.noreply.github.com>
Signed-off-by: Victor Khaustov <3192677+vi3itor@users.noreply.github.com>
Signed-off-by: AlvinC <alvincny529@gmail.com>
Signed-off-by: Tyler Lum <tylergwlum@gmail.com>
Signed-off-by: Miguel Alonso Jr. <76960110+miguelalonsojr@users.noreply.github.com>
Signed-off-by: renaudponcelet <renaud.poncelet@gmail.com>
Co-authored-by: lotusl-code <lotusl@nvidia.com>
Co-authored-by: Kelly Guo <kellyg@nvidia.com>
Co-authored-by: jaczhangnv <jaczhang@nvidia.com>
Co-authored-by: rwiltz <165190220+rwiltz@users.noreply.github.com>
Co-authored-by: Yanzi Zhu <yanziz@nvidia.com>
Co-authored-by: nv-mhaselton <mhaselton@nvidia.com>
Co-authored-by: cosmith-nvidia <141183495+cosmith-nvidia@users.noreply.github.com>
Co-authored-by: Michael Gussert <michael@gussert.com>
Co-authored-by: CY Chen <cyc@nvidia.com>
Co-authored-by: oahmednv <oahmed@Nvidia.com>
Co-authored-by: Ashwin Varghese Kuruttukulam <123109010+ashwinvkNV@users.noreply.github.com>
Co-authored-by: Rafael Wiltz <rwiltz@nvidia.com>
Co-authored-by: Peter Du <peterd@nvidia.com>
Co-authored-by: chengronglai <chengrongl@nvidia.com>
Co-authored-by: pulkitg01 <pulkitg@nvidia.com>
Co-authored-by: Connor Smith <cosmith@nvidia.com>
Co-authored-by: Ashwin Varghese Kuruttukulam <ashwinvk@nvidia.com>
Co-authored-by: Kelly Guo <kellyguo123@hotmail.com>
Co-authored-by: shauryadNv <shauryad@nvidia.com>
Co-authored-by: Mayank Mittal <12863862+Mayankm96@users.noreply.github.com>
Co-authored-by: samibouziri <79418773+samibouziri@users.noreply.github.com>
Co-authored-by: James Smith <142246516+jsmith-bdai@users.noreply.github.com>
Co-authored-by: Shundo Kishi <syundo0730@gmail.com>
Co-authored-by: Sheikh Dawood <sabdulajees@nvidia.com>
Co-authored-by: Toni-SM <aserranomuno@nvidia.com>
Co-authored-by: Gonglitian <70052908+Gonglitian@users.noreply.github.com>
Co-authored-by: James Tigue <166445701+jtigue-bdai@users.noreply.github.com>
Co-authored-by: Mayank Mittal <mittalma@leggedrobotics.com>
Co-authored-by: Kyle Morgenstein <34984693+KyleM73@users.noreply.github.com>
Co-authored-by: Johnson Sun <20457146+j3soon@users.noreply.github.com>
Co-authored-by: Pascal Roth <57946385+pascal-roth@users.noreply.github.com>
Co-authored-by: Hongyu Li <lihongyu0807@icloud.com>
Co-authored-by: Jean-Francois-Lafleche <57650687+Jean-Francois-Lafleche@users.noreply.github.com>
Co-authored-by: Wei Jinqi <changshanshi@outlook.com>
Co-authored-by: Louis LE LAY <le.lay.louis@gmail.com>
Co-authored-by: Harsh Patel <hapatel@theaiinstitute.com>
Co-authored-by: Kousheek Chakraborty <kousheekc@gmail.com>
Co-authored-by: Victor Khaustov <3192677+vi3itor@users.noreply.github.com>
Co-authored-by: AlvinC <alvincny529@gmail.com>
Co-authored-by: Felipe Mohr <50018670+felipemohr@users.noreply.github.com>
Co-authored-by: AdAstra7 <87345760+likecanyon@users.noreply.github.com>
Co-authored-by: gao <ziqi.gao@iff-extern.fraunhofer.de>
Co-authored-by: Tyler Lum <tylergwlum@gmail.com>
Co-authored-by: -T.K.- <t_k_233@outlook.com>
Co-authored-by: Clemens Schwarke <96480707+ClemensSchwarke@users.noreply.github.com>
Co-authored-by: Miguel Alonso Jr. <76960110+miguelalonsojr@users.noreply.github.com>
Co-authored-by: Miguel Alonso Jr. <miguel.alonso@nfinite.app>
Co-authored-by: renaudponcelet <renaud.poncelet@gmail.com>
Co-authored-by: Ales Borovicka <aborovicka@nvidia.com>
Co-authored-by: nv-mm <mmagdics@nvidia.com>
Co-authored-by: Antoine RICHARD <antoiner@nvidia.com>
Co-authored-by: dvangelder-nvidia <dvangelder@nvidia.com>
Co-authored-by: Octi Zhang <zhengyuz@nvidia.com>

apps/isaacsim_4_5/isaaclab.python.headless.kit

@@ -163,7 +163,7 @@ folders = [
     "${exe-path}/../isaacsim/extscache",  # isaac cache extensions for pip
     "${exe-path}/../isaacsim/extsPhysics",  # isaac physics extensions for pip
     "${app}", # needed to find other app files
-    "${app}/../source", # needed to find extensions in Isaac Lab
+    "${app}/../../source", # needed to find extensions in Isaac Lab
 ]
 
 [settings.ngx]

apps/isaacsim_4_5/isaaclab.python.headless.rendering.kit

@@ -130,7 +130,7 @@ folders = [
     "${exe-path}/../isaacsim/extscache",  # isaac cache extensions for pip
     "${exe-path}/../isaacsim/extsPhysics",  # isaac physics extensions for pip
     "${app}", # needed to find other app files
-    "${app}/../source", # needed to find extensions in Isaac Lab
+    "${app}/../../source", # needed to find extensions in Isaac Lab
 ]
 
 # Asset path

apps/isaacsim_4_5/isaaclab.python.kit

@@ -274,7 +274,7 @@ folders = [
     "${exe-path}/../isaacsim/extscache",  # isaac cache extensions for pip
     "${exe-path}/../isaacsim/extsPhysics",  # isaac physics extensions for pip
     "${app}", # needed to find other app files
-    "${app}/../source", # needed to find extensions in Isaac Lab
+    "${app}/../../source", # needed to find extensions in Isaac Lab
 ]
 
 [settings.physics]

apps/isaacsim_4_5/isaaclab.python.rendering.kit

@@ -128,7 +128,7 @@ folders = [
     "${exe-path}/../isaacsim/extscache",  # isaac cache extensions for pip
     "${exe-path}/../isaacsim/extsPhysics",  # isaac physics extensions for pip
     "${app}", # needed to find other app files
-    "${app}/../source", # needed to find extensions in Isaac Lab
+    "${app}/../../source", # needed to find extensions in Isaac Lab
 ]
 
 # Asset path

apps/isaacsim_4_5/isaaclab.python.xr.openxr.headless.kit

@@ -37,5 +37,5 @@ folders = [
     "${exe-path}/../isaacsim/extscache",  # isaac cache extensions for pip
     "${exe-path}/../isaacsim/extsPhysics",  # isaac physics extensions for pip
     "${app}", # needed to find other app files
-    "${app}/../source", # needed to find extensions in Isaac Lab
+    "${app}/../../source", # needed to find extensions in Isaac Lab
 ]

apps/isaacsim_4_5/isaaclab.python.xr.openxr.kit

@@ -59,7 +59,7 @@ folders = [
     "${exe-path}/../isaacsim/extscache",  # isaac cache extensions for pip
     "${exe-path}/../isaacsim/extsPhysics",  # isaac physics extensions for pip
     "${app}", # needed to find other app files
-    "${app}/../source", # needed to find extensions in Isaac Lab
+    "${app}/../../source", # needed to find extensions in Isaac Lab
 ]
 
 # Asset path

isaaclab.bat

@@ -38,6 +38,33 @@ if not exist "%isaac_path%" (
 )
 goto :eof
 
+rem -----------------------------------------------------------------------
+rem Returns success (exit code 0) if Isaac Sim's version starts with "4.5"
+rem -----------------------------------------------------------------------
+:is_isaacsim_version_4_5
+    rem make sure we have %python_exe%
+    call :extract_python_exe
+
+    rem 1) try to locate the VERSION file via the kit install
+    for /f "delims=" %%V in ('!python_exe! -c "import isaacsim,os;print(os.path.abspath(os.path.join(os.path.dirname(isaacsim.__file__), os.pardir, os.pardir, 'VERSION')))"') do set "VERSION_PATH=%%V"
+    if exist "!VERSION_PATH!" (
+        for /f "usebackq delims=" %%L in ("!VERSION_PATH!") do set "ISAACSIM_VER=%%L"
+    ) else (
+        rem 2) fallback to importlib.metadata if no VERSION file
+        for /f "delims=" %%L in ('!python_exe! -c "from importlib.metadata import version;print(version(''isaacsim''))"') do set "ISAACSIM_VER=%%L"
+    )
+
+    rem Clean up the version string (remove any trailing whitespace or newlines)
+    set "ISAACSIM_VER=!ISAACSIM_VER: =!"
+
+    rem Use string comparison instead of findstr for more reliable matching
+    if "!ISAACSIM_VER:~0,3!"=="4.5" (
+        exit /b 0
+    ) else (
+        exit /b 1
+    )
+    goto :eof
+
 rem extract the python from isaacsim
 :extract_python_exe
 rem check if using conda
@@ -132,6 +159,30 @@ if %errorlevel% equ 0 (
 ) else (
     echo [INFO] Creating conda environment named '%env_name%'...
     echo [INFO] Installing dependencies from %ISAACLAB_PATH%\environment.yml
+    rem ————————————————————————————————
+    rem patch Python version if needed, but back up first
+    rem ————————————————————————————————
+    copy "%ISAACLAB_PATH%environment.yml" "%ISAACLAB_PATH%environment.yml.bak" >nul
+    call :is_isaacsim_version_4_5
+    if !ERRORLEVEL! EQU 0 (
+        echo [INFO] Detected Isaac Sim 4.5 --^> forcing python=3.10
+        rem Use findstr to replace the python version line
+        (
+            for /f "delims=" %%L in ('type "%ISAACLAB_PATH%environment.yml"') do (
+                set "line=%%L"
+                set "line=!line: =!"
+                if "!line:~0,15!"=="-python=3.11" (
+                    echo   - python=3.10
+                ) else (
+                    echo %%L
+                )
+            )
+        ) > "%ISAACLAB_PATH%environment.yml.tmp"
+        rem Replace the original file with the modified version
+        move /y "%ISAACLAB_PATH%environment.yml.tmp" "%ISAACLAB_PATH%environment.yml" >nul
+    ) else (
+        echo [INFO] Isaac Sim ^>=5.0, installing python=3.11
+    )
     call conda env create -y --file %ISAACLAB_PATH%\environment.yml -n %env_name%
 )
 rem cache current paths for later

isaaclab.sh

@@ -43,6 +43,35 @@ install_system_deps() {
     fi
 }
 
+is_isaacsim_version_4_5() {
+    local python_exe
+    python_exe=$(extract_python_exe)
+
+    # 1) Try the VERSION file
+    local sim_file
+    sim_file=$("${python_exe}" -c "import isaacsim; print(isaacsim.__file__)" 2>/dev/null) || return 1
+    local version_path
+    version_path=$(dirname "${sim_file}")/../../VERSION
+    if [[ -f "${version_path}" ]]; then
+        local ver
+        ver=$(head -n1 "${version_path}")
+        [[ "${ver}" == 4.5* ]] && return 0
+    fi
+
+    # 2) Fallback to importlib.metadata via a here-doc
+    local ver
+    ver=$("${python_exe}" <<'PYCODE' 2>/dev/null
+from importlib.metadata import version, PackageNotFoundError
+try:
+    print(version("isaacsim"))
+except PackageNotFoundError:
+    import sys; sys.exit(1)
+PYCODE
+) || return 1
+
+    [[ "${ver}" == 4.5* ]]
+}
+
 # check if running in docker
 is_docker() {
     [ -f /.dockerenv ] || \
@@ -171,8 +200,20 @@ setup_conda_env() {
         echo -e "[INFO] Creating conda environment named '${env_name}'..."
         echo -e "[INFO] Installing dependencies from ${ISAACLAB_PATH}/environment.yml"
 
-        # Create environment from YAML file with specified name
+        # patch Python version if needed, but back up first
+        cp "${ISAACLAB_PATH}/environment.yml"{,.bak}
+        if is_isaacsim_version_4_5; then
+            echo "[INFO] Detected Isaac Sim 4.5 → forcing python=3.10"
+            sed -i 's/^  - python=3\.11/  - python=3.10/' "${ISAACLAB_PATH}/environment.yml"
+        else
+            echo "[INFO] Isaac Sim 5.0, installing python=3.11"
+        fi
+
         conda env create -y --file ${ISAACLAB_PATH}/environment.yml -n ${env_name}
+        # (optional) restore original environment.yml:
+        if [[ -f "${ISAACLAB_PATH}/environment.yml.bak" ]]; then
+            mv "${ISAACLAB_PATH}/environment.yml.bak" "${ISAACLAB_PATH}/environment.yml"
+        fi
     fi
 
     # cache current paths for later

scripts/tutorials/00_sim/spawn_prims.py

@@ -96,10 +96,8 @@ def main():
     sim = sim_utils.SimulationContext(sim_cfg)
     # Set main camera
     sim.set_camera_view([2.0, 0.0, 2.5], [-0.5, 0.0, 0.5])
-
-    # Design scene by adding assets to it
+    # Design scene
     design_scene()
-
     # Play the simulator
     sim.reset()
     # Now we are ready!

scripts/tutorials/01_assets/add_new_robot.py

@@ -24,14 +24,11 @@ simulation_app = app_launcher.app
 import numpy as np
 import torch
 
-import isaacsim.core.utils.stage as stage_utils
-
 import isaaclab.sim as sim_utils
 from isaaclab.actuators import ImplicitActuatorCfg
 from isaaclab.assets import AssetBaseCfg
 from isaaclab.assets.articulation import ArticulationCfg
 from isaaclab.scene import InteractiveScene, InteractiveSceneCfg
-from isaaclab.sim.utils import attach_stage_to_usd_context
 from isaaclab.utils.assets import ISAAC_NUCLEUS_DIR
 
 JETBOT_CONFIG = ArticulationCfg(
@@ -163,16 +160,12 @@ def run_simulator(sim: sim_utils.SimulationContext, scene: InteractiveScene):
 def main():
     """Main function."""
     # Initialize the simulation context
-    sim_cfg = sim_utils.SimulationCfg(device=args_cli.device, create_stage_in_memory=True)
+    sim_cfg = sim_utils.SimulationCfg(device=args_cli.device)
     sim = sim_utils.SimulationContext(sim_cfg)
-
     sim.set_camera_view([3.5, 0.0, 3.2], [0.0, 0.0, 0.5])
     # Design scene
     scene_cfg = NewRobotsSceneCfg(args_cli.num_envs, env_spacing=2.0)
-    # Create scene with stage in memory and then attach to USD context
-    with stage_utils.use_stage(sim.get_initial_stage()):
     scene = InteractiveScene(scene_cfg)
-        attach_stage_to_usd_context()
     # Play the simulator
     sim.reset()
     # Now we are ready!

scripts/tutorials/01_assets/run_articulation.py

@@ -35,12 +35,10 @@ simulation_app = app_launcher.app
 import torch
 
 import isaacsim.core.utils.prims as prim_utils
-import isaacsim.core.utils.stage as stage_utils
 
 import isaaclab.sim as sim_utils
 from isaaclab.assets import Articulation
 from isaaclab.sim import SimulationContext
-from isaaclab.sim.utils import attach_stage_to_usd_context
 
 ##
 # Pre-defined configs
@@ -123,14 +121,12 @@ def run_simulator(sim: sim_utils.SimulationContext, entities: dict[str, Articula
 def main():
     """Main function."""
     # Load kit helper
-    sim_cfg = sim_utils.SimulationCfg(device=args_cli.device, create_stage_in_memory=True)
+    sim_cfg = sim_utils.SimulationCfg(device=args_cli.device)
     sim = SimulationContext(sim_cfg)
     # Set main camera
     sim.set_camera_view([2.5, 0.0, 4.0], [0.0, 0.0, 2.0])
-    # Create scene with stage in memory and then attach to USD context
-    with stage_utils.use_stage(sim.get_initial_stage()):
+    # Design scene
     scene_entities, scene_origins = design_scene()
-        attach_stage_to_usd_context()
     scene_origins = torch.tensor(scene_origins, device=sim.device)
     # Play the simulator
     sim.reset()

scripts/tutorials/01_assets/run_deformable_object.py

@@ -36,13 +36,11 @@ simulation_app = app_launcher.app
 import torch
 
 import isaacsim.core.utils.prims as prim_utils
-import isaacsim.core.utils.stage as stage_utils
 
 import isaaclab.sim as sim_utils
 import isaaclab.utils.math as math_utils
 from isaaclab.assets import DeformableObject, DeformableObjectCfg
 from isaaclab.sim import SimulationContext
-from isaaclab.sim.utils import attach_stage_to_usd_context
 
 
 def design_scene():
@@ -148,14 +146,12 @@ def run_simulator(sim: sim_utils.SimulationContext, entities: dict[str, Deformab
 def main():
     """Main function."""
     # Load kit helper
-    sim_cfg = sim_utils.SimulationCfg(device=args_cli.device, create_stage_in_memory=True)
+    sim_cfg = sim_utils.SimulationCfg(device=args_cli.device)
     sim = SimulationContext(sim_cfg)
     # Set main camera
     sim.set_camera_view(eye=[3.0, 0.0, 1.0], target=[0.0, 0.0, 0.5])
-    # Create scene with stage in memory and then attach to USD context
-    with stage_utils.use_stage(sim.get_initial_stage()):
+    # Design scene
     scene_entities, scene_origins = design_scene()
-        attach_stage_to_usd_context()
     scene_origins = torch.tensor(scene_origins, device=sim.device)
     # Play the simulator
     sim.reset()

scripts/tutorials/01_assets/run_rigid_object.py

@@ -36,13 +36,11 @@ simulation_app = app_launcher.app
 import torch
 
 import isaacsim.core.utils.prims as prim_utils
-import isaacsim.core.utils.stage as stage_utils
 
 import isaaclab.sim as sim_utils
 import isaaclab.utils.math as math_utils
 from isaaclab.assets import RigidObject, RigidObjectCfg
 from isaaclab.sim import SimulationContext
-from isaaclab.sim.utils import attach_stage_to_usd_context
 
 
 def design_scene():
@@ -128,14 +126,12 @@ def run_simulator(sim: sim_utils.SimulationContext, entities: dict[str, RigidObj
 def main():
     """Main function."""
     # Load kit helper
-    sim_cfg = sim_utils.SimulationCfg(device=args_cli.device, create_stage_in_memory=True)
+    sim_cfg = sim_utils.SimulationCfg(device=args_cli.device)
     sim = SimulationContext(sim_cfg)
     # Set main camera
     sim.set_camera_view(eye=[1.5, 0.0, 1.0], target=[0.0, 0.0, 0.0])
-    # Create scene with stage in memory and then attach to USD context
-    with stage_utils.use_stage(sim.get_initial_stage()):
+    # Design scene
     scene_entities, scene_origins = design_scene()
-        attach_stage_to_usd_context()
     scene_origins = torch.tensor(scene_origins, device=sim.device)
     # Play the simulator
     sim.reset()

scripts/tutorials/01_assets/run_surface_gripper.py

@@ -36,12 +36,10 @@ simulation_app = app_launcher.app
 import torch
 
 import isaacsim.core.utils.prims as prim_utils
-import isaacsim.core.utils.stage as stage_utils
 
 import isaaclab.sim as sim_utils
 from isaaclab.assets import Articulation, SurfaceGripper, SurfaceGripperCfg
 from isaaclab.sim import SimulationContext
-from isaaclab.sim.utils import attach_stage_to_usd_context
 
 ##
 # Pre-defined configs
@@ -168,10 +166,7 @@ def main():
     # Set main camera
     sim.set_camera_view([2.75, 7.5, 10.0], [2.75, 0.0, 0.0])
     # Design scene
-    # Create scene with stage in memory and then attach to USD context
-    with stage_utils.use_stage(sim.get_initial_stage()):
     scene_entities, scene_origins = design_scene()
-        attach_stage_to_usd_context()
     scene_origins = torch.tensor(scene_origins, device=sim.device)
     # Play the simulator
     sim.reset()

scripts/tutorials/02_scene/create_scene.py

@@ -35,13 +35,10 @@ simulation_app = app_launcher.app
 
 import torch
 
-import isaacsim.core.utils.stage as stage_utils
-
 import isaaclab.sim as sim_utils
 from isaaclab.assets import ArticulationCfg, AssetBaseCfg
 from isaaclab.scene import InteractiveScene, InteractiveSceneCfg
 from isaaclab.sim import SimulationContext
-from isaaclab.sim.utils import attach_stage_to_usd_context
 from isaaclab.utils import configclass
 
 ##
@@ -113,16 +110,13 @@ def run_simulator(sim: sim_utils.SimulationContext, scene: InteractiveScene):
 def main():
     """Main function."""
     # Load kit helper
-    sim_cfg = sim_utils.SimulationCfg(device=args_cli.device, create_stage_in_memory=True)
+    sim_cfg = sim_utils.SimulationCfg(device=args_cli.device)
     sim = SimulationContext(sim_cfg)
     # Set main camera
     sim.set_camera_view([2.5, 0.0, 4.0], [0.0, 0.0, 2.0])
     # Design scene
     scene_cfg = CartpoleSceneCfg(num_envs=args_cli.num_envs, env_spacing=2.0)
-    # Create scene with stage in memory and then attach to USD context
-    with stage_utils.use_stage(sim.get_initial_stage()):
     scene = InteractiveScene(scene_cfg)
-        attach_stage_to_usd_context()
     # Play the simulator
     sim.reset()
     # Now we are ready!

scripts/tutorials/03_envs/create_cartpole_base_env.py

@@ -141,7 +141,6 @@ def main():
     env_cfg = CartpoleEnvCfg()
     env_cfg.scene.num_envs = args_cli.num_envs
     env_cfg.sim.device = args_cli.device
-    env_cfg.sim.create_stage_in_memory = True
     # setup base environment
     env = ManagerBasedEnv(cfg=env_cfg)
 

scripts/tutorials/03_envs/create_cube_base_env.py

@@ -315,7 +315,6 @@ def main():
 
     # setup base environment
     env_cfg = CubeEnvCfg()
-    env_cfg.sim.create_stage_in_memory = True
     env = ManagerBasedEnv(cfg=env_cfg)
 
     # setup target position commands

scripts/tutorials/03_envs/create_quadruped_base_env.py

@@ -205,7 +205,6 @@ def main():
     """Main function."""
     # setup base environment
     env_cfg = QuadrupedEnvCfg()
-    env_cfg.sim.create_stage_in_memory = True
     env = ManagerBasedEnv(cfg=env_cfg)
 
     # load level policy

scripts/tutorials/03_envs/policy_inference_in_usd.py

@@ -70,7 +70,6 @@ def main():
     env_cfg.sim.device = args_cli.device
     if args_cli.device == "cpu":
         env_cfg.sim.use_fabric = False
-    env_cfg.sim.create_stage_in_memory = True
 
     # create environment
     env = ManagerBasedRLEnv(cfg=env_cfg)

scripts/tutorials/03_envs/run_cartpole_rl_env.py

@@ -46,7 +46,6 @@ def main():
     env_cfg = CartpoleEnvCfg()
     env_cfg.scene.num_envs = args_cli.num_envs
     env_cfg.sim.device = args_cli.device
-    env_cfg.sim.create_stage_in_memory = True
     # setup RL environment
     env = ManagerBasedRLEnv(cfg=env_cfg)
 

scripts/tutorials/04_sensors/add_sensors_on_robot.py

@@ -41,13 +41,10 @@ simulation_app = app_launcher.app
 
 import torch
 
-import isaacsim.core.utils.stage as stage_utils
-
 import isaaclab.sim as sim_utils
 from isaaclab.assets import ArticulationCfg, AssetBaseCfg
 from isaaclab.scene import InteractiveScene, InteractiveSceneCfg
 from isaaclab.sensors import CameraCfg, ContactSensorCfg, RayCasterCfg, patterns
-from isaaclab.sim.utils import attach_stage_to_usd_context
 from isaaclab.utils import configclass
 
 ##
@@ -160,16 +157,13 @@ def main():
     """Main function."""
 
     # Initialize the simulation context
-    sim_cfg = sim_utils.SimulationCfg(dt=0.005, device=args_cli.device, create_stage_in_memory=True)
+    sim_cfg = sim_utils.SimulationCfg(dt=0.005, device=args_cli.device)
     sim = sim_utils.SimulationContext(sim_cfg)
     # Set main camera
     sim.set_camera_view(eye=[3.5, 3.5, 3.5], target=[0.0, 0.0, 0.0])
     # Design scene
     scene_cfg = SensorsSceneCfg(num_envs=args_cli.num_envs, env_spacing=2.0)
-    # Create scene with stage in memory and then attach to USD context
-    with stage_utils.use_stage(sim.get_initial_stage()):
     scene = InteractiveScene(scene_cfg)
-        attach_stage_to_usd_context()
     # Play the simulator
     sim.reset()
     # Now we are ready!

scripts/tutorials/04_sensors/run_frame_transformer.py

@@ -35,7 +35,6 @@ simulation_app = app_launcher.app
 import math
 import torch
 
-import isaacsim.core.utils.stage as stage_utils
 import isaacsim.util.debug_draw._debug_draw as omni_debug_draw
 
 import isaaclab.sim as sim_utils
@@ -45,7 +44,6 @@ from isaaclab.markers import VisualizationMarkers
 from isaaclab.markers.config import FRAME_MARKER_CFG
 from isaaclab.sensors import FrameTransformer, FrameTransformerCfg, OffsetCfg
 from isaaclab.sim import SimulationContext
-from isaaclab.sim.utils import attach_stage_to_usd_context
 
 ##
 # Pre-defined configs
@@ -166,14 +164,12 @@ def run_simulator(sim: sim_utils.SimulationContext, scene_entities: dict):
 def main():
     """Main function."""
     # Load kit helper
-    sim_cfg = sim_utils.SimulationCfg(dt=0.005, device=args_cli.device, create_stage_in_memory=True)
+    sim_cfg = sim_utils.SimulationCfg(dt=0.005, device=args_cli.device)
     sim = SimulationContext(sim_cfg)
     # Set main camera
     sim.set_camera_view(eye=[2.5, 2.5, 2.5], target=[0.0, 0.0, 0.0])
-    # Create scene with stage in memory and then attach to USD context
-    with stage_utils.use_stage(sim.get_initial_stage()):
+    # Design scene
     scene_entities = design_scene()
-        attach_stage_to_usd_context()
     # Play the simulator
     sim.reset()
     # Now we are ready!

scripts/tutorials/04_sensors/run_ray_caster.py

@@ -34,12 +34,10 @@ simulation_app = app_launcher.app
 import torch
 
 import isaacsim.core.utils.prims as prim_utils
-import isaacsim.core.utils.stage as stage_utils
 
 import isaaclab.sim as sim_utils
 from isaaclab.assets import RigidObject, RigidObjectCfg
 from isaaclab.sensors.ray_caster import RayCaster, RayCasterCfg, patterns
-from isaaclab.sim.utils import attach_stage_to_usd_context
 from isaaclab.utils.assets import ISAAC_NUCLEUS_DIR
 from isaaclab.utils.timer import Timer
 
@@ -132,14 +130,12 @@ def run_simulator(sim: sim_utils.SimulationContext, scene_entities: dict):
 def main():
     """Main function."""
     # Load simulation context
-    sim_cfg = sim_utils.SimulationCfg(device=args_cli.device, create_stage_in_memory=True)
+    sim_cfg = sim_utils.SimulationCfg(device=args_cli.device)
     sim = sim_utils.SimulationContext(sim_cfg)
     # Set main camera
     sim.set_camera_view([0.0, 15.0, 15.0], [0.0, 0.0, -2.5])
-    # Create scene with stage in memory and then attach to USD context
-    with stage_utils.use_stage(sim.get_initial_stage()):
+    # Design scene
     scene_entities = design_scene()
-        attach_stage_to_usd_context()
     # Play simulator
     sim.reset()
     # Now we are ready!

scripts/tutorials/04_sensors/run_ray_caster_camera.py

@@ -39,12 +39,10 @@ import os
 import torch
 
 import isaacsim.core.utils.prims as prim_utils
-import isaacsim.core.utils.stage as stage_utils
 import omni.replicator.core as rep
 
 import isaaclab.sim as sim_utils
 from isaaclab.sensors.ray_caster import RayCasterCamera, RayCasterCameraCfg, patterns
-from isaaclab.sim.utils import attach_stage_to_usd_context
 from isaaclab.utils import convert_dict_to_backend
 from isaaclab.utils.assets import ISAAC_NUCLEUS_DIR
 from isaaclab.utils.math import project_points, unproject_depth
@@ -165,14 +163,12 @@ def run_simulator(sim: sim_utils.SimulationContext, scene_entities: dict):
 def main():
     """Main function."""
     # Load kit helper
-    sim_cfg = sim_utils.SimulationCfg(create_stage_in_memory=True)
+    sim_cfg = sim_utils.SimulationCfg()
     sim = sim_utils.SimulationContext(sim_cfg)
     # Set main camera
     sim.set_camera_view([2.5, 2.5, 3.5], [0.0, 0.0, 0.0])
-    # Create scene with stage in memory and then attach to USD context
-    with stage_utils.use_stage(sim.get_initial_stage()):
+    # Design scene
     scene_entities = design_scene()
-        attach_stage_to_usd_context()
     # Play simulator
     sim.reset()
     # Now we are ready!

scripts/tutorials/04_sensors/run_usd_camera.py

@@ -66,7 +66,6 @@ import random
 import torch
 
 import isaacsim.core.utils.prims as prim_utils
-import isaacsim.core.utils.stage as stage_utils
 import omni.replicator.core as rep
 
 import isaaclab.sim as sim_utils
@@ -75,7 +74,6 @@ from isaaclab.markers import VisualizationMarkers
 from isaaclab.markers.config import RAY_CASTER_MARKER_CFG
 from isaaclab.sensors.camera import Camera, CameraCfg
 from isaaclab.sensors.camera.utils import create_pointcloud_from_depth
-from isaaclab.sim.utils import attach_stage_to_usd_context
 from isaaclab.utils import convert_dict_to_backend
 
 
@@ -270,14 +268,12 @@ def run_simulator(sim: sim_utils.SimulationContext, scene_entities: dict):
 def main():
     """Main function."""
     # Load simulation context
-    sim_cfg = sim_utils.SimulationCfg(device=args_cli.device, create_stage_in_memory=True)
+    sim_cfg = sim_utils.SimulationCfg(device=args_cli.device)
     sim = sim_utils.SimulationContext(sim_cfg)
     # Set main camera
     sim.set_camera_view([2.5, 2.5, 2.5], [0.0, 0.0, 0.0])
-    # Create scene with stage in memory and then attach to USD context
-    with stage_utils.use_stage(sim.get_initial_stage()):
+    # Design scene
     scene_entities = design_scene()
-        attach_stage_to_usd_context()
     # Play simulator
     sim.reset()
     # Now we are ready!

scripts/tutorials/05_controllers/run_diff_ik.py

@@ -39,8 +39,6 @@ simulation_app = app_launcher.app
 
 import torch
 
-import isaacsim.core.utils.stage as stage_utils
-
 import isaaclab.sim as sim_utils
 from isaaclab.assets import AssetBaseCfg
 from isaaclab.controllers import DifferentialIKController, DifferentialIKControllerCfg
@@ -48,7 +46,6 @@ from isaaclab.managers import SceneEntityCfg
 from isaaclab.markers import VisualizationMarkers
 from isaaclab.markers.config import FRAME_MARKER_CFG
 from isaaclab.scene import InteractiveScene, InteractiveSceneCfg
-from isaaclab.sim.utils import attach_stage_to_usd_context
 from isaaclab.utils import configclass
 from isaaclab.utils.assets import ISAAC_NUCLEUS_DIR
 from isaaclab.utils.math import subtract_frame_transforms
@@ -193,16 +190,13 @@ def run_simulator(sim: sim_utils.SimulationContext, scene: InteractiveScene):
 def main():
     """Main function."""
     # Load kit helper
-    sim_cfg = sim_utils.SimulationCfg(dt=0.01, device=args_cli.device, create_stage_in_memory=True)
+    sim_cfg = sim_utils.SimulationCfg(dt=0.01, device=args_cli.device)
     sim = sim_utils.SimulationContext(sim_cfg)
     # Set main camera
     sim.set_camera_view([2.5, 2.5, 2.5], [0.0, 0.0, 0.0])
     # Design scene
     scene_cfg = TableTopSceneCfg(num_envs=args_cli.num_envs, env_spacing=2.0)
-    # Create scene with stage in memory and then attach to USD context
-    with stage_utils.use_stage(sim.get_initial_stage()):
     scene = InteractiveScene(scene_cfg)
-        attach_stage_to_usd_context()
     # Play the simulator
     sim.reset()
     # Now we are ready!

scripts/tutorials/05_controllers/run_osc.py

@@ -38,8 +38,6 @@ simulation_app = app_launcher.app
 
 import torch
 
-import isaacsim.core.utils.stage as stage_utils
-
 import isaaclab.sim as sim_utils
 from isaaclab.assets import Articulation, AssetBaseCfg
 from isaaclab.controllers import OperationalSpaceController, OperationalSpaceControllerCfg
@@ -47,7 +45,6 @@ from isaaclab.markers import VisualizationMarkers
 from isaaclab.markers.config import FRAME_MARKER_CFG
 from isaaclab.scene import InteractiveScene, InteractiveSceneCfg
 from isaaclab.sensors import ContactSensorCfg
-from isaaclab.sim.utils import attach_stage_to_usd_context
 from isaaclab.utils import configclass
 from isaaclab.utils.math import (
     combine_frame_transforms,
@@ -465,16 +462,13 @@ def convert_to_task_frame(osc: OperationalSpaceController, command: torch.tensor
 def main():
     """Main function."""
     # Load kit helper
-    sim_cfg = sim_utils.SimulationCfg(dt=0.01, device=args_cli.device, create_stage_in_memory=True)
+    sim_cfg = sim_utils.SimulationCfg(dt=0.01, device=args_cli.device)
     sim = sim_utils.SimulationContext(sim_cfg)
     # Set main camera
     sim.set_camera_view([2.5, 2.5, 2.5], [0.0, 0.0, 0.0])
     # Design scene
     scene_cfg = SceneCfg(num_envs=args_cli.num_envs, env_spacing=2.0)
-    # Create scene with stage in memory and then attach to USD context
-    with stage_utils.use_stage(sim.get_initial_stage()):
     scene = InteractiveScene(scene_cfg)
-        attach_stage_to_usd_context()
     # Play the simulator
     sim.reset()
     # Now we are ready!

source/isaaclab/isaaclab/app/app_launcher.py

@@ -362,16 +362,6 @@ class AppLauncher:
             ),
         )
         # special flag for backwards compatibility
-        arg_group.add_argument(
-            "--use_isaacsim_45",
-            type=bool,
-            default=False,
-            help=(
-                "Uses previously version of Isaac Sim 4.5. This will reference the Isaac Sim 4.5 compatible app files"
-                " and will result in some features being unavailable. For full feature set, please update to Isaac Sim"
-                " 5.0."
-            ),
-        )
 
         # Corresponding to the beginning of the function,
         # if we have removed -h/--help handling, we add it back.
@@ -714,7 +704,8 @@ class AppLauncher:
         kit_app_exp_path = os.environ["EXP_PATH"]
         isaaclab_app_exp_path = os.path.join(os.path.dirname(os.path.abspath(__file__)), *[".."] * 4, "apps")
         # For Isaac Sim 4.5 compatibility, we use the 4.5 app files in a different folder
-        if launcher_args.get("use_isaacsim_45", False):
+        # if launcher_args.get("use_isaacsim_45", False):
+        if self.is_isaac_sim_version_4_5():
             isaaclab_app_exp_path = os.path.join(isaaclab_app_exp_path, "isaacsim_4_5")
 
         if self._sim_experience_file == "":
@@ -770,7 +761,7 @@ class AppLauncher:
         if recording_enabled:
             if self._headless:
                 raise ValueError("Animation recording is not supported in headless mode.")
-            if launcher_args.get("use_isaacsim_45", False):
+            if self.is_isaac_sim_version_4_5():
                 raise RuntimeError(
                     "Animation recording is not supported in Isaac Sim 4.5. Please update to Isaac Sim 5.0."
                 )
@@ -890,6 +881,8 @@ class AppLauncher:
 
         # parse preset file
         repo_path = os.path.join(carb.tokens.get_tokens_interface().resolve("${app}"), "..")
+        if self.is_isaac_sim_version_4_5():
+            repo_path = os.path.join(repo_path, "..")
         preset_filename = os.path.join(repo_path, f"apps/rendering_modes/{rendering_mode}.kit")
         with open(preset_filename) as file:
             preset_dict = toml.load(file)
@@ -935,6 +928,30 @@ class AppLauncher:
         # raise the error for keyboard interrupt
         raise KeyboardInterrupt
 
+    def is_isaac_sim_version_4_5(self) -> bool:
+        if not hasattr(self, "_is_sim_ver_4_5"):
+            # 1) Try to read the VERSION file (for manual / binary installs)
+            version_path = os.path.abspath(os.path.join(os.path.dirname(isaacsim.__file__), "../../VERSION"))
+            if os.path.isfile(version_path):
+                with open(version_path) as f:
+                    ver = f.readline().strip()
+                    if ver.startswith("4.5"):
+                        self._is_sim_ver_4_5 = True
+                        return True
+
+            # 2) Fall back to metadata (for pip installs)
+            from importlib.metadata import version as pkg_version
+
+            try:
+                ver = pkg_version("isaacsim")
+                if ver.startswith("4.5"):
+                    self._is_sim_ver_4_5 = True
+                else:
+                    self._is_sim_ver_4_5 = False
+            except Exception:
+                self._is_sim_ver_4_5 = False
+        return self._is_sim_ver_4_5
+
     def _hide_play_button(self, flag):
         """Hide/Unhide the play button in the toolbar.
 

source/isaaclab/isaaclab/assets/articulation/articulation.py

@@ -1361,6 +1361,21 @@ class Articulation(AssetBase):
         if self._root_physx_view._backend is None:
             raise RuntimeError(f"Failed to create articulation at: {root_prim_path_expr}. Please check PhysX logs.")
 
+        if int(get_version()[2]) < 5:
+            omni.log.warn(
+                "Spatial tendons are not supported in Isaac Sim < 5.0: patching spatial-tendon getter"
+                " and setter to use dummy value"
+            )
+            self._root_physx_view.max_spatial_tendons = 0
+            self._root_physx_view.get_spatial_tendon_stiffnesses = lambda: torch.empty(0, device=self.device)
+            self._root_physx_view.get_spatial_tendon_dampings = lambda: torch.empty(0, device=self.device)
+            self._root_physx_view.get_spatial_tendon_limit_stiffnesses = lambda: torch.empty(0, device=self.device)
+            self._root_physx_view.get_spatial_tendon_offsets = lambda: torch.empty(0, device=self.device)
+            self._root_physx_view.set_spatial_tendon_properties = lambda *args, **kwargs: omni.log.warn(
+                "Spatial tendons are not supported in Isaac Sim < 5.0: Calling"
+                " set_spatial_tendon_properties has no effect"
+            )
+
         # log information about the articulation
         omni.log.info(f"Articulation initialized at: {self.cfg.prim_path} with root '{root_prim_path_expr}'.")
         omni.log.info(f"Is fixed root: {self.is_fixed_base}")
@@ -1578,14 +1593,6 @@ class Articulation(AssetBase):
         self._spatial_tendon_names = list()
         # parse fixed tendons properties if they exist
         if self.num_fixed_tendons > 0 or self.num_spatial_tendons > 0:
-            # for spatial tendons, check if we are using isaac sim 5.0
-            if self.num_spatial_tendons > 0:
-                isaac_sim_version = get_version()
-                # checks for Isaac Sim v5.0 as spatial tendons are only available since 5.0
-                if int(isaac_sim_version[2]) < 5:
-                    raise RuntimeError(
-                        "Spatial tendons are not available in Isaac Sim 4.5. Please update to Isaac Sim 5.0."
-                    )
 
             joint_paths = self.root_physx_view.dof_paths[0]
 

source/isaaclab/isaaclab/assets/asset_base.py

@@ -21,6 +21,7 @@ from isaacsim.core.simulation_manager import IsaacEvents, SimulationManager
 from isaacsim.core.utils.stage import get_current_stage
 
 import isaaclab.sim as sim_utils
+from isaaclab.sim import SimulationContext
 
 if TYPE_CHECKING:
     from .asset_base_cfg import AssetBaseCfg
@@ -92,23 +93,40 @@ class AssetBase(ABC):
         if len(matching_prims) == 0:
             raise RuntimeError(f"Could not find prim with path {self.cfg.prim_path}.")
 
-        # note: Use weakref on all callbacks to ensure that this object can be deleted when its destructor is called.
+        # register simulator callbacks (with weakref safety to avoid crashes on deletion)
+        def safe_callback(callback_name, event, obj_ref):
+            """Safely invoke a callback on a weakly-referenced object, ignoring ReferenceError if deleted."""
+            try:
+                obj = obj_ref
+                getattr(obj, callback_name)(event)
+            except ReferenceError:
+                # Object has been deleted; ignore.
+                pass
+
+        # note: use weakref on callbacks to ensure that this object can be deleted when its destructor is called.
         # add callbacks for stage play/stop
-        # The order is set to 10 which is arbitrary but should be lower priority than the default order of 0
+        obj_ref = weakref.proxy(self)
         timeline_event_stream = omni.timeline.get_timeline_interface().get_timeline_event_stream()
+
+        # the order is set to 10 which is arbitrary but should be lower priority than the default order of 0
+        # register timeline PLAY event callback (lower priority with order=10)
         self._initialize_handle = timeline_event_stream.create_subscription_to_pop_by_type(
             int(omni.timeline.TimelineEventType.PLAY),
-            lambda event, obj=weakref.proxy(self): obj._initialize_callback(event),
+            lambda event, obj_ref=obj_ref: safe_callback("_initialize_callback", event, obj_ref),
             order=10,
         )
+        # register timeline STOP event callback (lower priority with order=10)
         self._invalidate_initialize_handle = timeline_event_stream.create_subscription_to_pop_by_type(
             int(omni.timeline.TimelineEventType.STOP),
-            lambda event, obj=weakref.proxy(self): obj._invalidate_initialize_callback(event),
+            lambda event, obj_ref=obj_ref: safe_callback("_invalidate_initialize_callback", event, obj_ref),
             order=10,
         )
+        # register prim deletion callback
         self._prim_deletion_callback_id = SimulationManager.register_callback(
-            self._on_prim_deletion, event=IsaacEvents.PRIM_DELETION
+            lambda event, obj_ref=obj_ref: safe_callback("_on_prim_deletion", event, obj_ref),
+            event=IsaacEvents.PRIM_DELETION,
         )
+
         # add handle for debug visualization (this is set to a valid handle inside set_debug_vis)
         self._debug_vis_handle = None
         # set initial state of debug visualization
@@ -314,6 +332,9 @@ class AssetBase(ABC):
         Note:
             This function is called when the prim is deleted.
         """
+        # skip callback if required
+        if getattr(SimulationContext.instance(), "_skip_next_prim_deletion_callback_fn", False):
+            return
         if prim_path == "/":
             self._clear_callbacks()
             return

source/isaaclab/isaaclab/assets/rigid_object/rigid_object_data.py

@@ -7,9 +7,9 @@ import torch
 import weakref
 
 import omni.physics.tensors.impl.api as physx
-from isaacsim.core.utils.stage import get_current_stage_id
 
 import isaaclab.utils.math as math_utils
+from isaaclab.sim.utils import get_current_stage_id
 from isaaclab.utils.buffers import TimestampedBuffer
 
 

source/isaaclab/isaaclab/assets/rigid_object_collection/rigid_object_collection.py

@@ -21,6 +21,7 @@ from pxr import UsdPhysics
 import isaaclab.sim as sim_utils
 import isaaclab.utils.math as math_utils
 import isaaclab.utils.string as string_utils
+from isaaclab.sim import SimulationContext
 
 from ..asset_base import AssetBase
 from .rigid_object_collection_data import RigidObjectCollectionData
@@ -92,23 +93,40 @@ class RigidObjectCollection(AssetBase):
         # stores object names
         self._object_names_list = []
 
-        # note: Use weakref on all callbacks to ensure that this object can be deleted when its destructor is called.
+        # register simulator callbacks (with weakref safety to avoid crashes on deletion)
+        def safe_callback(callback_name, event, obj_ref):
+            """Safely invoke a callback on a weakly-referenced object, ignoring ReferenceError if deleted."""
+            try:
+                obj = obj_ref
+                getattr(obj, callback_name)(event)
+            except ReferenceError:
+                # Object has been deleted; ignore.
+                pass
+
+        # note: use weakref on callbacks to ensure that this object can be deleted when its destructor is called.
         # add callbacks for stage play/stop
-        # The order is set to 10 which is arbitrary but should be lower priority than the default order of 0
+        obj_ref = weakref.proxy(self)
         timeline_event_stream = omni.timeline.get_timeline_interface().get_timeline_event_stream()
+
+        # the order is set to 10 which is arbitrary but should be lower priority than the default order of 0
+        # register timeline PLAY event callback (lower priority with order=10)
         self._initialize_handle = timeline_event_stream.create_subscription_to_pop_by_type(
             int(omni.timeline.TimelineEventType.PLAY),
-            lambda event, obj=weakref.proxy(self): obj._initialize_callback(event),
+            lambda event, obj_ref=obj_ref: safe_callback("_initialize_callback", event, obj_ref),
             order=10,
         )
+        # register timeline STOP event callback (lower priority with order=10)
         self._invalidate_initialize_handle = timeline_event_stream.create_subscription_to_pop_by_type(
             int(omni.timeline.TimelineEventType.STOP),
-            lambda event, obj=weakref.proxy(self): obj._invalidate_initialize_callback(event),
+            lambda event, obj_ref=obj_ref: safe_callback("_invalidate_initialize_callback", event, obj_ref),
             order=10,
         )
+        # register prim deletion callback
         self._prim_deletion_callback_id = SimulationManager.register_callback(
-            self._on_prim_deletion, event=IsaacEvents.PRIM_DELETION
+            lambda event, obj_ref=obj_ref: safe_callback("_on_prim_deletion", event, obj_ref),
+            event=IsaacEvents.PRIM_DELETION,
         )
+
         self._debug_vis_handle = None
 
     """
@@ -711,6 +729,9 @@ class RigidObjectCollection(AssetBase):
         Note:
             This function is called when the prim is deleted.
         """
+        # skip callback if required
+        if getattr(SimulationContext.instance(), "_skip_next_prim_deletion_callback_fn", False):
+            return
         if prim_path == "/":
             self._clear_callbacks()
             return

source/isaaclab/isaaclab/assets/rigid_object_collection/rigid_object_collection_data.py

@@ -7,9 +7,9 @@ import torch
 import weakref
 
 import omni.physics.tensors.impl.api as physx
-from isaacsim.core.utils.stage import get_current_stage_id
 
 import isaaclab.utils.math as math_utils
+from isaaclab.sim.utils import get_current_stage_id
 from isaaclab.utils.buffers import TimestampedBuffer
 
 

source/isaaclab/isaaclab/assets/surface_gripper/surface_gripper.py

@@ -68,22 +68,39 @@ class SurfaceGripper(AssetBase):
         # flag for whether the sensor is initialized
         self._is_initialized = False
         self._debug_vis_handle = None
+
+        # Register simulator callbacks (with weakref safety to avoid crashes on deletion)
+        def safe_callback(callback_name, event, obj_ref):
+            """Safely invoke a callback on a weakly-referenced object, ignoring ReferenceError if deleted."""
+            try:
+                obj = obj_ref
+                getattr(obj, callback_name)(event)
+            except ReferenceError:
+                # Object has been deleted; ignore.
+                pass
+
         # note: Use weakref on callbacks to ensure that this object can be deleted when its destructor is called.
         # add callbacks for stage play/stop
-        # The order is set to 10 which is arbitrary but should be lower priority than the default order of 0
+        obj_ref = weakref.proxy(self)
         timeline_event_stream = omni.timeline.get_timeline_interface().get_timeline_event_stream()
+
+        # The order is set to 10 which is arbitrary but should be lower priority than the default order of 0
+        # Register timeline PLAY event callback (lower priority with order=10)
         self._initialize_handle = timeline_event_stream.create_subscription_to_pop_by_type(
             int(omni.timeline.TimelineEventType.PLAY),
-            lambda event, obj=weakref.proxy(self): obj._initialize_callback(event),
+            lambda event, obj_ref=obj_ref: safe_callback("_initialize_callback", event, obj_ref),
             order=10,
         )
+        # Register timeline STOP event callback (lower priority with order=10)
         self._invalidate_initialize_handle = timeline_event_stream.create_subscription_to_pop_by_type(
             int(omni.timeline.TimelineEventType.STOP),
-            lambda event, obj=weakref.proxy(self): obj._invalidate_initialize_callback(event),
+            lambda event, obj_ref=obj_ref: safe_callback("_invalidate_initialize_callback", event, obj_ref),
             order=10,
         )
+        # Register prim deletion callback
         self._prim_deletion_callback_id = SimulationManager.register_callback(
-            self._on_prim_deletion, event=IsaacEvents.PRIM_DELETION
+            lambda event, obj_ref=obj_ref: safe_callback("_on_prim_deletion", event, obj_ref),
+            event=IsaacEvents.PRIM_DELETION,
         )
 
     """

source/isaaclab/isaaclab/envs/direct_marl_env.py

@@ -17,16 +17,16 @@ from collections.abc import Sequence
 from dataclasses import MISSING
 from typing import Any, ClassVar
 
-import isaacsim.core.utils.stage as stage_utils
 import isaacsim.core.utils.torch as torch_utils
 import omni.kit.app
 import omni.log
+import omni.physx
 from isaacsim.core.version import get_version
 
 from isaaclab.managers import EventManager
 from isaaclab.scene import InteractiveScene
 from isaaclab.sim import SimulationContext
-from isaaclab.sim.utils import attach_stage_to_usd_context
+from isaaclab.sim.utils import attach_stage_to_usd_context, use_stage
 from isaaclab.utils.noise import NoiseModel
 from isaaclab.utils.timer import Timer
 
@@ -119,7 +119,8 @@ class DirectMARLEnv(gym.Env):
 
         # generate scene
         with Timer("[INFO]: Time taken for scene creation", "scene_creation"):
-            with stage_utils.use_stage(self.sim.get_initial_stage()):
+            # set the stage context for scene creation steps which use the stage
+            with use_stage(self.sim.get_initial_stage()):
                 self.scene = InteractiveScene(self.cfg.scene)
                 self._setup_scene()
                 attach_stage_to_usd_context()
@@ -150,6 +151,9 @@ class DirectMARLEnv(gym.Env):
         if builtins.ISAAC_LAUNCHED_FROM_TERMINAL is False:
             print("[INFO]: Starting the simulation. This may take a few seconds. Please wait...")
             with Timer("[INFO]: Time taken for simulation start", "simulation_start"):
+                # since the reset can trigger callbacks which use the stage,
+                # we need to set the stage context here
+                with use_stage(self.sim.get_initial_stage()):
                     self.sim.reset()
                 # update scene to pre populate data buffers for assets and sensors.
                 # this is needed for the observation manager to get valid tensors for initialization.
@@ -534,9 +538,18 @@ class DirectMARLEnv(gym.Env):
             del self.scene
             if self.viewport_camera_controller is not None:
                 del self.viewport_camera_controller
+
             # clear callbacks and instance
+            if float(".".join(get_version()[2])) >= 5:
+                if self.cfg.sim.create_stage_in_memory:
+                    # detach physx stage
+                    omni.physx.get_physx_simulation_interface().detach_stage()
+                    self.sim.stop()
+                    self.sim.clear()
+
             self.sim.clear_all_callbacks()
             self.sim.clear_instance()
+
             # destroy the window
             if self._window is not None:
                 self._window = None

source/isaaclab/isaaclab/envs/direct_rl_env.py

@@ -17,17 +17,17 @@ from collections.abc import Sequence
 from dataclasses import MISSING
 from typing import Any, ClassVar
 
-import isaacsim.core.utils.stage as stage_utils
 import isaacsim.core.utils.torch as torch_utils
 import omni.kit.app
 import omni.log
+import omni.physx
 from isaacsim.core.simulation_manager import SimulationManager
 from isaacsim.core.version import get_version
 
 from isaaclab.managers import EventManager
 from isaaclab.scene import InteractiveScene
 from isaaclab.sim import SimulationContext
-from isaaclab.sim.utils import attach_stage_to_usd_context
+from isaaclab.sim.utils import attach_stage_to_usd_context, use_stage
 from isaaclab.utils.noise import NoiseModel
 from isaaclab.utils.timer import Timer
 
@@ -125,7 +125,8 @@ class DirectRLEnv(gym.Env):
 
         # generate scene
         with Timer("[INFO]: Time taken for scene creation", "scene_creation"):
-            with stage_utils.use_stage(self.sim.get_initial_stage()):
+            # set the stage context for scene creation steps which use the stage
+            with use_stage(self.sim.get_initial_stage()):
                 self.scene = InteractiveScene(self.cfg.scene)
                 self._setup_scene()
                 attach_stage_to_usd_context()
@@ -156,6 +157,9 @@ class DirectRLEnv(gym.Env):
         if builtins.ISAAC_LAUNCHED_FROM_TERMINAL is False:
             print("[INFO]: Starting the simulation. This may take a few seconds. Please wait...")
             with Timer("[INFO]: Time taken for simulation start", "simulation_start"):
+                # since the reset can trigger callbacks which use the stage,
+                # we need to set the stage context here
+                with use_stage(self.sim.get_initial_stage()):
                     self.sim.reset()
                 # update scene to pre populate data buffers for assets and sensors.
                 # this is needed for the observation manager to get valid tensors for initialization.
@@ -489,9 +493,18 @@ class DirectRLEnv(gym.Env):
             del self.scene
             if self.viewport_camera_controller is not None:
                 del self.viewport_camera_controller
+
             # clear callbacks and instance
+            if float(".".join(get_version()[2])) >= 5:
+                if self.cfg.sim.create_stage_in_memory:
+                    # detach physx stage
+                    omni.physx.get_physx_simulation_interface().detach_stage()
+                    self.sim.stop()
+                    self.sim.clear()
+
             self.sim.clear_all_callbacks()
             self.sim.clear_instance()
+
             # destroy the window
             if self._window is not None:
                 self._window = None

source/isaaclab/isaaclab/envs/manager_based_env.py

@@ -8,15 +8,16 @@ import torch
 from collections.abc import Sequence
 from typing import Any
 
-import isaacsim.core.utils.stage as stage_utils
 import isaacsim.core.utils.torch as torch_utils
 import omni.log
+import omni.physx
 from isaacsim.core.simulation_manager import SimulationManager
+from isaacsim.core.version import get_version
 
 from isaaclab.managers import ActionManager, EventManager, ObservationManager, RecorderManager
 from isaaclab.scene import InteractiveScene
 from isaaclab.sim import SimulationContext
-from isaaclab.sim.utils import attach_stage_to_usd_context
+from isaaclab.sim.utils import attach_stage_to_usd_context, use_stage
 from isaaclab.ui.widgets import ManagerLiveVisualizer
 from isaaclab.utils.timer import Timer
 
@@ -129,8 +130,8 @@ class ManagerBasedEnv:
 
         # generate scene
         with Timer("[INFO]: Time taken for scene creation", "scene_creation"):
-            # get stage handle and set stage context
-            with stage_utils.use_stage(self.sim.get_initial_stage()):
+            # set the stage context for scene creation steps which use the stage
+            with use_stage(self.sim.get_initial_stage()):
                 self.scene = InteractiveScene(self.cfg.scene)
                 attach_stage_to_usd_context()
         print("[INFO]: Scene manager: ", self.scene)
@@ -159,6 +160,9 @@ class ManagerBasedEnv:
         if builtins.ISAAC_LAUNCHED_FROM_TERMINAL is False:
             print("[INFO]: Starting the simulation. This may take a few seconds. Please wait...")
             with Timer("[INFO]: Time taken for simulation start", "simulation_start"):
+                # since the reset can trigger callbacks which use the stage,
+                # we need to set the stage context here
+                with use_stage(self.sim.get_initial_stage()):
                     self.sim.reset()
                 # update scene to pre populate data buffers for assets and sensors.
                 # this is needed for the observation manager to get valid tensors for initialization.
@@ -457,9 +461,18 @@ class ManagerBasedEnv:
             del self.event_manager
             del self.recorder_manager
             del self.scene
+
             # clear callbacks and instance
+            if float(".".join(get_version()[2])) >= 5:
+                if self.cfg.sim.create_stage_in_memory:
+                    # detach physx stage
+                    omni.physx.get_physx_simulation_interface().detach_stage()
+                    self.sim.stop()
+                    self.sim.clear()
+
             self.sim.clear_all_callbacks()
             self.sim.clear_instance()
+
             # destroy the window
             if self._window is not None:
                 self._window = None

source/isaaclab/isaaclab/markers/visualization_markers.py

@@ -32,7 +32,7 @@ from pxr import Gf, PhysxSchema, Sdf, Usd, UsdGeom, UsdPhysics, Vt
 
 import isaaclab.sim as sim_utils
 from isaaclab.sim.spawners import SpawnerCfg
-from isaaclab.sim.utils import attach_stage_to_usd_context, is_current_stage_in_memory
+from isaaclab.sim.utils import attach_stage_to_usd_context
 from isaaclab.utils.configclass import configclass
 from isaaclab.utils.math import convert_quat
 
@@ -400,12 +400,7 @@ class VisualizationMarkers:
             if child_prim.IsA(UsdGeom.Gprim):
                 # early attach stage to usd context if stage is in memory
                 # since stage in memory is not supported by the "ChangePropertyCommand" kit command
-                if is_current_stage_in_memory():
-                    omni.log.warn(
-                        "Attaching stage in memory to USD context early to support omni kit command during stage"
-                        " creation."
-                    )
-                    attach_stage_to_usd_context()
+                attach_stage_to_usd_context(attaching_early=True)
 
                 # invisible to secondary rays such as depth images
                 omni.kit.commands.execute(

source/isaaclab/isaaclab/scene/interactive_scene.py

@@ -12,7 +12,7 @@ import omni.log
 import omni.usd
 from isaacsim.core.cloner import GridCloner
 from isaacsim.core.prims import XFormPrim
-from isaacsim.core.utils.stage import get_current_stage, get_current_stage_id
+from isaacsim.core.utils.stage import get_current_stage
 from pxr import PhysxSchema
 
 import isaaclab.sim as sim_utils
@@ -31,6 +31,7 @@ from isaaclab.assets import (
 )
 from isaaclab.sensors import ContactSensorCfg, FrameTransformerCfg, SensorBase, SensorBaseCfg
 from isaaclab.sim import SimulationContext
+from isaaclab.sim.utils import get_current_stage_id
 from isaaclab.terrains import TerrainImporter, TerrainImporterCfg
 
 from .interactive_scene_cfg import InteractiveSceneCfg

source/isaaclab/isaaclab/sensors/sensor_base.py

@@ -26,6 +26,7 @@ from isaacsim.core.simulation_manager import IsaacEvents, SimulationManager
 from isaacsim.core.utils.stage import get_current_stage
 
 import isaaclab.sim as sim_utils
+from isaaclab.sim import SimulationContext
 
 if TYPE_CHECKING:
     from .sensor_base_cfg import SensorBaseCfg
@@ -63,23 +64,40 @@ class SensorBase(ABC):
         # get stage handle
         self.stage = get_current_stage()
 
-        # note: Use weakref on callbacks to ensure that this object can be deleted when its destructor is called.
+        # register simulator callbacks (with weakref safety to avoid crashes on deletion)
+        def safe_callback(callback_name, event, obj_ref):
+            """Safely invoke a callback on a weakly-referenced object, ignoring ReferenceError if deleted."""
+            try:
+                obj = obj_ref
+                getattr(obj, callback_name)(event)
+            except ReferenceError:
+                # Object has been deleted; ignore.
+                pass
+
+        # note: use weakref on callbacks to ensure that this object can be deleted when its destructor is called.
         # add callbacks for stage play/stop
-        # The order is set to 10 which is arbitrary but should be lower priority than the default order of 0
+        obj_ref = weakref.proxy(self)
         timeline_event_stream = omni.timeline.get_timeline_interface().get_timeline_event_stream()
+
+        # the order is set to 10 which is arbitrary but should be lower priority than the default order of 0
+        # register timeline PLAY event callback (lower priority with order=10)
         self._initialize_handle = timeline_event_stream.create_subscription_to_pop_by_type(
             int(omni.timeline.TimelineEventType.PLAY),
-            lambda event, obj=weakref.proxy(self): obj._initialize_callback(event),
+            lambda event, obj_ref=obj_ref: safe_callback("_initialize_callback", event, obj_ref),
             order=10,
         )
+        # register timeline STOP event callback (lower priority with order=10)
         self._invalidate_initialize_handle = timeline_event_stream.create_subscription_to_pop_by_type(
             int(omni.timeline.TimelineEventType.STOP),
-            lambda event, obj=weakref.proxy(self): obj._invalidate_initialize_callback(event),
+            lambda event, obj_ref=obj_ref: safe_callback("_invalidate_initialize_callback", event, obj_ref),
             order=10,
         )
+        # register prim deletion callback
         self._prim_deletion_callback_id = SimulationManager.register_callback(
-            self._on_prim_deletion, event=IsaacEvents.PRIM_DELETION
+            lambda event, obj_ref=obj_ref: safe_callback("_on_prim_deletion", event, obj_ref),
+            event=IsaacEvents.PRIM_DELETION,
         )
+
         # add handle for debug visualization (this is set to a valid handle inside set_debug_vis)
         self._debug_vis_handle = None
         # set initial state of debug visualization
@@ -293,6 +311,9 @@ class SensorBase(ABC):
         Note:
             This function is called when the prim is deleted.
         """
+        # skip callback if required
+        if getattr(SimulationContext.instance(), "_skip_next_prim_deletion_callback_fn", False):
+            return
         if prim_path == "/":
             self._clear_callbacks()
             return

source/isaaclab/isaaclab/sim/simulation_cfg.py

@@ -341,7 +341,7 @@ class SimulationCfg:
     """Render settings. Default is RenderCfg()."""
 
     create_stage_in_memory: bool = False
-    """If stage is first created in memory and then attached to usd context for simulation and rendering.
+    """If stage is first created in memory. Default is False.
 
     Creating the stage in memory can reduce start-up time.
     """

source/isaaclab/isaaclab/sim/simulation_context.py

@@ -31,6 +31,8 @@ from isaacsim.core.utils.viewports import set_camera_view
 from isaacsim.core.version import get_version
 from pxr import Gf, PhysxSchema, Usd, UsdPhysics
 
+from isaaclab.sim.utils import create_new_stage_in_memory, use_stage
+
 from .simulation_cfg import SimulationCfg
 from .spawners import DomeLightCfg, GroundPlaneCfg
 from .utils import bind_physics_material
@@ -131,7 +133,7 @@ class SimulationContext(_SimulationContext):
 
         # create stage in memory if requested
         if self.cfg.create_stage_in_memory:
-            self._initial_stage = stage_utils.create_new_stage_in_memory()
+            self._initial_stage = create_new_stage_in_memory()
         else:
             self._initial_stage = omni.usd.get_context().get_stage()
 
@@ -241,14 +243,18 @@ class SimulationContext(_SimulationContext):
             self._app_control_on_stop_handle = None
         self._disable_app_control_on_stop_handle = False
 
+        # flag for skipping prim deletion callback
+        # when stage in memory is attached
+        self._skip_next_prim_deletion_callback_fn = False
+
         # flatten out the simulation dictionary
         sim_params = self.cfg.to_dict()
         if sim_params is not None:
             if "physx" in sim_params:
                 physx_params = sim_params.pop("physx")
                 sim_params.update(physx_params)
-        # create a simulation context to control the simulator
 
+        # add warning about enabling stabilization for large step sizes
         if not self.cfg.physx.enable_stabilization and (self.cfg.dt > 0.0333):
             omni.log.warn(
                 "Large simulation step size (> 0.0333 seconds) is not recommended without enabling stabilization."
@@ -256,6 +262,19 @@ class SimulationContext(_SimulationContext):
                 " simulation step size if you run into physics issues."
             )
 
+        # create a simulation context to control the simulator
+        if float(".".join(self._isaacsim_version[2])) < 5:
+            # stage arg is not supported before isaac sim 5.0
+            super().__init__(
+                stage_units_in_meters=1.0,
+                physics_dt=self.cfg.dt,
+                rendering_dt=self.cfg.dt * self.cfg.render_interval,
+                backend="torch",
+                sim_params=sim_params,
+                physics_prim_path=self.cfg.physics_prim_path,
+                device=self.cfg.device,
+            )
+        else:
             super().__init__(
                 stage_units_in_meters=1.0,
                 physics_dt=self.cfg.dt,
@@ -676,7 +695,7 @@ class SimulationContext(_SimulationContext):
 
     def _init_stage(self, *args, **kwargs) -> Usd.Stage:
         _ = super()._init_stage(*args, **kwargs)
-        with stage_utils.use_stage(self.get_initial_stage()):
+        with use_stage(self.get_initial_stage()):
             # a stage update here is needed for the case when physics_dt != rendering_dt, otherwise the app crashes
             # when in headless mode
             self.set_setting("/app/player/playSimulations", False)

source/isaaclab/isaaclab/sim/spawners/from_files/from_files.py

@@ -253,7 +253,15 @@ def _spawn_from_usd_file(
 
     # check file path exists
     if not stage.ResolveIdentifierToEditTarget(usd_path):
-        raise FileNotFoundError(f"USD file not found at path: '{usd_path}'.")
+        if "4.5" in usd_path:
+            usd_5_0_path = (
+                usd_path.replace("http", "https").replace("-production.", "-staging.").replace("/4.5", "/5.0")
+            )
+            if not stage.ResolveIdentifierToEditTarget(usd_5_0_path):
+                raise FileNotFoundError(f"USD file not found at path at either: '{usd_path}' or '{usd_5_0_path}'.")
+            usd_path = usd_5_0_path
+        else:
+            raise FileNotFoundError(f"USD file not found at path at: '{usd_path}'.")
     # spawn asset if it doesn't exist.
     if not prim_utils.is_prim_path_valid(prim_path):
         # add prim as reference to stage

source/isaaclab/isaaclab/sim/spawners/materials/visual_materials.py

@@ -12,12 +12,7 @@ import omni.kit.commands
 import omni.log
 from pxr import Usd
 
-from isaaclab.sim.utils import (
-    attach_stage_to_usd_context,
-    clone,
-    is_current_stage_in_memory,
-    safe_set_attribute_on_usd_prim,
-)
+from isaaclab.sim.utils import attach_stage_to_usd_context, clone, safe_set_attribute_on_usd_prim
 from isaaclab.utils.assets import NVIDIA_NUCLEUS_DIR
 
 if TYPE_CHECKING:
@@ -56,12 +51,7 @@ def spawn_preview_surface(prim_path: str, cfg: visual_materials_cfg.PreviewSurfa
     if not prim_utils.is_prim_path_valid(prim_path):
         # early attach stage to usd context if stage is in memory
         # since stage in memory is not supported by the "CreatePreviewSurfaceMaterialPrim" kit command
-        if is_current_stage_in_memory():
-            omni.log.warn(
-                "Attaching stage in memory to USD context early to support an operation which doesn't support stage in"
-                " memory."
-            )
-            attach_stage_to_usd_context()
+        attach_stage_to_usd_context(attaching_early=True)
 
         omni.kit.commands.execute("CreatePreviewSurfaceMaterialPrim", mtl_path=prim_path, select_new_prim=False)
     else:
@@ -111,12 +101,7 @@ def spawn_from_mdl_file(prim_path: str, cfg: visual_materials_cfg.MdlMaterialCfg
     if not prim_utils.is_prim_path_valid(prim_path):
         # early attach stage to usd context if stage is in memory
         # since stage in memory is not supported by the "CreateMdlMaterialPrim" kit command
-        if is_current_stage_in_memory():
-            omni.log.warn(
-                "Attaching stage in memory to USD context early to support an operation which doesn't support stage in"
-                " memory."
-            )
-            attach_stage_to_usd_context()
+        attach_stage_to_usd_context(attaching_early=True)
 
         # extract material name from path
         material_name = cfg.mdl_path.split("/")[-1].split(".")[0]

source/isaaclab/isaaclab/sim/spawners/sensors/sensors.py

@@ -12,7 +12,7 @@ import omni.kit.commands
 import omni.log
 from pxr import Sdf, Usd
 
-from isaaclab.sim.utils import attach_stage_to_usd_context, clone, is_current_stage_in_memory
+from isaaclab.sim.utils import attach_stage_to_usd_context, clone
 from isaaclab.utils import to_camel_case
 
 if TYPE_CHECKING:
@@ -90,12 +90,7 @@ def spawn_camera(
     if cfg.lock_camera:
         # early attach stage to usd context if stage is in memory
         # since stage in memory is not supported by the "ChangePropertyCommand" kit command
-        if is_current_stage_in_memory():
-            omni.log.warn(
-                "Attaching stage in memory to USD context early to support an operation which doesn't support stage in"
-                " memory."
-            )
-            attach_stage_to_usd_context()
+        attach_stage_to_usd_context(attaching_early=True)
 
         omni.kit.commands.execute(
             "ChangePropertyCommand",

source/isaaclab/isaaclab/sim/utils.py

@@ -7,6 +7,7 @@
 
 from __future__ import annotations
 
+import contextlib
 import functools
 import inspect
 import re
@@ -20,8 +21,9 @@ import omni.kit.commands
 import omni.log
 from isaacsim.core.cloner import Cloner
 from isaacsim.core.utils.carb import get_carb_setting
-from isaacsim.core.utils.stage import get_current_stage, get_current_stage_id
-from pxr import PhysxSchema, Sdf, Usd, UsdGeom, UsdPhysics, UsdShade
+from isaacsim.core.utils.stage import get_current_stage
+from isaacsim.core.version import get_version
+from pxr import PhysxSchema, Sdf, Usd, UsdGeom, UsdPhysics, UsdShade, UsdUtils
 
 # from Isaac Sim 4.2 onwards, pxr.Semantics is deprecated
 try:
@@ -115,12 +117,7 @@ def safe_set_attribute_on_usd_prim(prim: Usd.Prim, attr_name: str, value: Any, c
 
     # early attach stage to usd context if stage is in memory
     # since stage in memory is not supported by the "ChangePropertyCommand" kit command
-    if is_current_stage_in_memory():
-        omni.log.warn(
-            "Attaching stage in memory to USD context early to support an operation which doesn't support stage in"
-            " memory."
-        )
-        attach_stage_to_usd_context()
+    attach_stage_to_usd_context(attaching_early=True)
 
     # change property
     omni.kit.commands.execute(
@@ -819,32 +816,55 @@ Stage management.
 """
 
 
-def attach_stage_to_usd_context():
+def attach_stage_to_usd_context(attaching_early: bool = False):
     """Attaches stage in memory to usd context.
 
     This function should be called during or after scene is created and before stage is simulated or rendered.
 
     Note:
         If the stage is not in memory or rendering is not enabled, this function will return without attaching.
-    """
 
-    import omni.physxfabric
+    Args:
+        attaching_early: Whether to attach the stage to the usd context before stage is created. Defaults to False.
+    """
 
     from isaaclab.sim.simulation_context import SimulationContext
 
+    # if Isaac Sim version is less than 5.0, stage in memory is not supported
+    isaac_sim_version = float(".".join(get_version()[2]))
+    if isaac_sim_version < 5:
+        return
+
+    # if stage is not in memory, we can return early
+    if not is_current_stage_in_memory():
+        return
+
+    # attach stage to physx
+    stage_id = get_current_stage_id()
+    physx_sim_interface = omni.physx.get_physx_simulation_interface()
+    physx_sim_interface.attach_stage(stage_id)
+
     # this carb flag is equivalent to if rendering is enabled
     carb_setting = carb.settings.get_settings()
     is_rendering_enabled = get_carb_setting(carb_setting, "/physics/fabricUpdateTransformations")
 
-    # if stage is not in memory or rendering is not enabled, we don't need to attach it
-    if not is_current_stage_in_memory() or not is_rendering_enabled:
+    # if rendering is not enabled, we don't need to attach it
+    if not is_rendering_enabled:
         return
 
-    stage_id = get_current_stage_id()
+    # early attach warning msg
+    if attaching_early:
+        omni.log.warn(
+            "Attaching stage in memory to USD context early to support an operation which doesn't support stage in"
+            " memory."
+        )
 
     # skip this callback to avoid wiping the stage after attachment
     SimulationContext.instance().skip_next_stage_open_callback()
 
+    # skip this callback to avoid clearing the prims
+    SimulationContext.instance()._skip_next_prim_deletion_callback_fn = True
+
     # enable physics fabric
     SimulationContext.instance()._physics_context.enable_fabric(True)
 
@@ -855,6 +875,8 @@ def attach_stage_to_usd_context():
     physx_sim_interface = omni.physx.get_physx_simulation_interface()
     physx_sim_interface.attach_stage(stage_id)
 
+    SimulationContext.instance()._skip_next_prim_deletion_callback_fn = False
+
 
 def is_current_stage_in_memory() -> bool:
     """This function checks if the current stage is in memory.
@@ -866,11 +888,11 @@ def is_current_stage_in_memory() -> bool:
     """
 
     # grab current stage id
-    stage_id = stage_utils.get_current_stage_id()
+    stage_id = get_current_stage_id()
 
     # grab context stage id
     context_stage = omni.usd.get_context().get_stage()
-    with stage_utils.use_stage(context_stage):
+    with use_stage(context_stage):
         context_stage_id = get_current_stage_id()
 
     # check if stage ids are the same
@@ -955,3 +977,59 @@ def select_usd_variants(prim_path: str, variants: object | dict[str, str], stage
                 f"Setting variant selection '{variant_selection}' for variant set '{variant_set_name}' on"
                 f" prim '{prim_path}'."
             )
+
+
+"""
+Isaac Sim stage utils wrappers to enable backwards compatibility to Isaac Sim 4.5
+"""
+
+
+@contextlib.contextmanager
+def use_stage(stage: Usd.Stage) -> None:
+    """Context manager that sets a thread-local stage, if supported.
+
+    In Isaac Sim < 5.0, this is a no-op to maintain compatibility.
+
+    Args:
+        stage (Usd.Stage): The stage to set temporarily.
+    """
+    isaac_sim_version = float(".".join(get_version()[2]))
+    if isaac_sim_version < 5:
+        omni.log.warn("[Compat] Isaac Sim < 5.0 does not support thread-local stage contexts. Skipping use_stage().")
+        yield  # no-op
+    else:
+        with stage_utils.use_stage(stage):
+            yield
+
+
+def create_new_stage_in_memory() -> Usd.Stage:
+    """Create a new stage in memory, if supported.
+
+    Returns:
+        The new stage.
+    """
+    isaac_sim_version = float(".".join(get_version()[2]))
+    if isaac_sim_version < 5:
+        omni.log.warn(
+            "[Compat] Isaac Sim < 5.0 does not support creating a new stage in memory. Falling back to creating a new"
+            " stage attached to USD context."
+        )
+        return stage_utils.create_new_stage()
+    else:
+        return stage_utils.create_new_stage_in_memory()
+
+
+def get_current_stage_id() -> int:
+    """Get the current open stage id.
+
+    Reimplementation of stage_utils.get_current_stage_id() for Isaac Sim < 5.0.
+
+    Returns:
+        int: The stage id.
+    """
+    stage = get_current_stage()
+    stage_cache = UsdUtils.StageCache.Get()
+    stage_id = stage_cache.GetId(stage).ToLongInt()
+    if stage_id < 0:
+        stage_id = stage_cache.Insert(stage).ToLongInt()
+    return stage_id

source/isaaclab/test/assets/test_surface_gripper.py

@@ -20,6 +20,7 @@ import torch
 
 import isaacsim.core.utils.prims as prim_utils
 import pytest
+from isaacsim.core.version import get_version
 
 import isaaclab.sim as sim_utils
 from isaaclab.actuators import ImplicitActuatorCfg
@@ -171,6 +172,9 @@ def test_initialization(sim, num_articulations, device, add_ground_plane) -> Non
         device: The device to run the test on.
         add_ground_plane: Whether to add a ground plane to the simulation.
     """
+    isaac_sim_version = get_version()
+    if int(isaac_sim_version[2]) < 5:
+        return
     surface_gripper_cfg, articulation_cfg = generate_surface_gripper_cfgs(kinematic_enabled=False)
     surface_gripper, articulation, _ = generate_surface_gripper(
         surface_gripper_cfg, articulation_cfg, num_articulations, device
@@ -202,6 +206,9 @@ def test_initialization(sim, num_articulations, device, add_ground_plane) -> Non
 @pytest.mark.parametrize("add_ground_plane", [True])
 def test_raise_error_if_not_cpu(sim, device, add_ground_plane) -> None:
     """Test that the SurfaceGripper raises an error if the device is not CPU."""
+    isaac_sim_version = get_version()
+    if int(isaac_sim_version[2]) < 5:
+        return
     num_articulations = 1
     surface_gripper_cfg, articulation_cfg = generate_surface_gripper_cfgs(kinematic_enabled=False)
     surface_gripper, articulation, translations = generate_surface_gripper(

source/isaaclab/test/devices/test_device_constructors.py

@@ -12,6 +12,7 @@ simulation_app = AppLauncher(headless=True).app
 
 """Rest everything follows."""
 
+import importlib
 import torch
 
 import pytest
@@ -104,9 +105,10 @@ def test_se2keyboard_constructors(mock_environment, mocker):
         v_y_sensitivity=0.5,
         omega_z_sensitivity=1.2,
     )
+    device_mod = importlib.import_module("isaaclab.devices.keyboard.se2_keyboard")
     mocker.patch.dict("sys.modules", {"carb": mock_environment["carb"], "omni": mock_environment["omni"]})
-    mocker.patch("isaaclab.devices.keyboard.se2_keyboard.carb", mock_environment["carb"])
-    mocker.patch("isaaclab.devices.keyboard.se2_keyboard.omni", mock_environment["omni"])
+    mocker.patch.object(device_mod, "carb", mock_environment["carb"])
+    mocker.patch.object(device_mod, "omni", mock_environment["omni"])
 
     keyboard = Se2Keyboard(config)
 
@@ -128,9 +130,10 @@ def test_se3keyboard_constructors(mock_environment, mocker):
         pos_sensitivity=0.5,
         rot_sensitivity=0.9,
     )
+    device_mod = importlib.import_module("isaaclab.devices.keyboard.se3_keyboard")
     mocker.patch.dict("sys.modules", {"carb": mock_environment["carb"], "omni": mock_environment["omni"]})
-    mocker.patch("isaaclab.devices.keyboard.se3_keyboard.carb", mock_environment["carb"])
-    mocker.patch("isaaclab.devices.keyboard.se3_keyboard.omni", mock_environment["omni"])
+    mocker.patch.object(device_mod, "carb", mock_environment["carb"])
+    mocker.patch.object(device_mod, "omni", mock_environment["omni"])
 
     keyboard = Se3Keyboard(config)
 
@@ -158,9 +161,10 @@ def test_se2gamepad_constructors(mock_environment, mocker):
         omega_z_sensitivity=1.2,
         dead_zone=0.02,
     )
+    device_mod = importlib.import_module("isaaclab.devices.gamepad.se2_gamepad")
     mocker.patch.dict("sys.modules", {"carb": mock_environment["carb"], "omni": mock_environment["omni"]})
-    mocker.patch("isaaclab.devices.gamepad.se2_gamepad.carb", mock_environment["carb"])
-    mocker.patch("isaaclab.devices.gamepad.se2_gamepad.omni", mock_environment["omni"])
+    mocker.patch.object(device_mod, "carb", mock_environment["carb"])
+    mocker.patch.object(device_mod, "omni", mock_environment["omni"])
 
     gamepad = Se2Gamepad(config)
 
@@ -184,9 +188,10 @@ def test_se3gamepad_constructors(mock_environment, mocker):
         rot_sensitivity=1.7,
         dead_zone=0.02,
     )
+    device_mod = importlib.import_module("isaaclab.devices.gamepad.se3_gamepad")
     mocker.patch.dict("sys.modules", {"carb": mock_environment["carb"], "omni": mock_environment["omni"]})
-    mocker.patch("isaaclab.devices.gamepad.se3_gamepad.carb", mock_environment["carb"])
-    mocker.patch("isaaclab.devices.gamepad.se3_gamepad.omni", mock_environment["omni"])
+    mocker.patch.object(device_mod, "carb", mock_environment["carb"])
+    mocker.patch.object(device_mod, "omni", mock_environment["omni"])
 
     gamepad = Se3Gamepad(config)
 
@@ -214,8 +219,9 @@ def test_se2spacemouse_constructors(mock_environment, mocker):
         v_y_sensitivity=0.5,
         omega_z_sensitivity=1.2,
     )
+    device_mod = importlib.import_module("isaaclab.devices.spacemouse.se2_spacemouse")
     mocker.patch.dict("sys.modules", {"hid": mock_environment["hid"]})
-    mocker.patch("isaaclab.devices.spacemouse.se2_spacemouse.hid", mock_environment["hid"])
+    mocker.patch.object(device_mod, "hid", mock_environment["hid"])
 
     spacemouse = Se2SpaceMouse(config)
 
@@ -238,8 +244,9 @@ def test_se3spacemouse_constructors(mock_environment, mocker):
         pos_sensitivity=0.5,
         rot_sensitivity=0.9,
     )
+    device_mod = importlib.import_module("isaaclab.devices.spacemouse.se3_spacemouse")
     mocker.patch.dict("sys.modules", {"hid": mock_environment["hid"]})
-    mocker.patch("isaaclab.devices.spacemouse.se3_spacemouse.hid", mock_environment["hid"])
+    mocker.patch.object(device_mod, "hid", mock_environment["hid"])
 
     spacemouse = Se3SpaceMouse(config)
 
@@ -274,6 +281,7 @@ def test_openxr_constructors(mock_environment, mocker):
     mock_head_retargeter = mocker.MagicMock()
     retargeters = [mock_controller_retargeter, mock_head_retargeter]
 
+    device_mod = importlib.import_module("isaaclab.devices.openxr.openxr_device")
     mocker.patch.dict(
         "sys.modules",
         {
@@ -282,12 +290,9 @@ def test_openxr_constructors(mock_environment, mocker):
             "isaacsim.core.prims": mocker.MagicMock(),
         },
     )
-    mocker.patch("isaaclab.devices.openxr.openxr_device.XRCore", mock_environment["omni"].kit.xr.core.XRCore)
-    mocker.patch(
-        "isaaclab.devices.openxr.openxr_device.XRPoseValidityFlags",
-        mock_environment["omni"].kit.xr.core.XRPoseValidityFlags,
-    )
-    mock_single_xform = mocker.patch("isaaclab.devices.openxr.openxr_device.SingleXFormPrim")
+    mocker.patch.object(device_mod, "XRCore", mock_environment["omni"].kit.xr.core.XRCore)
+    mocker.patch.object(device_mod, "XRPoseValidityFlags", mock_environment["omni"].kit.xr.core.XRPoseValidityFlags)
+    mock_single_xform = mocker.patch.object(device_mod, "SingleXFormPrim")
 
     # Configure the mock to return a string for prim_path
     mock_instance = mock_single_xform.return_value
@@ -330,9 +335,10 @@ def test_create_teleop_device_basic(mock_environment, mocker):
     devices_cfg = {"test_keyboard": keyboard_cfg}
 
     # Mock Se3Keyboard class
+    device_mod = importlib.import_module("isaaclab.devices.keyboard.se3_keyboard")
     mocker.patch.dict("sys.modules", {"carb": mock_environment["carb"], "omni": mock_environment["omni"]})
-    mocker.patch("isaaclab.devices.keyboard.se3_keyboard.carb", mock_environment["carb"])
-    mocker.patch("isaaclab.devices.keyboard.se3_keyboard.omni", mock_environment["omni"])
+    mocker.patch.object(device_mod, "carb", mock_environment["carb"])
+    mocker.patch.object(device_mod, "omni", mock_environment["omni"])
 
     # Create the device using the factory
     device = create_teleop_device("test_keyboard", devices_cfg)
@@ -358,6 +364,7 @@ def test_create_teleop_device_with_callbacks(mock_environment, mocker):
     callbacks = {"button_a": button_a_callback, "button_b": button_b_callback}
 
     # Mock OpenXRDevice class and dependencies
+    device_mod = importlib.import_module("isaaclab.devices.openxr.openxr_device")
     mocker.patch.dict(
         "sys.modules",
         {
@@ -366,12 +373,9 @@ def test_create_teleop_device_with_callbacks(mock_environment, mocker):
             "isaacsim.core.prims": mocker.MagicMock(),
         },
     )
-    mocker.patch("isaaclab.devices.openxr.openxr_device.XRCore", mock_environment["omni"].kit.xr.core.XRCore)
-    mocker.patch(
-        "isaaclab.devices.openxr.openxr_device.XRPoseValidityFlags",
-        mock_environment["omni"].kit.xr.core.XRPoseValidityFlags,
-    )
-    mock_single_xform = mocker.patch("isaaclab.devices.openxr.openxr_device.SingleXFormPrim")
+    mocker.patch.object(device_mod, "XRCore", mock_environment["omni"].kit.xr.core.XRCore)
+    mocker.patch.object(device_mod, "XRPoseValidityFlags", mock_environment["omni"].kit.xr.core.XRPoseValidityFlags)
+    mock_single_xform = mocker.patch.object(device_mod, "SingleXFormPrim")
 
     # Configure the mock to return a string for prim_path
     mock_instance = mock_single_xform.return_value
@@ -403,6 +407,7 @@ def test_create_teleop_device_with_retargeters(mock_environment, mocker):
     devices_cfg = {"test_xr": device_cfg}
 
     # Mock OpenXRDevice class and dependencies
+    device_mod = importlib.import_module("isaaclab.devices.openxr.openxr_device")
     mocker.patch.dict(
         "sys.modules",
         {
@@ -411,20 +416,18 @@ def test_create_teleop_device_with_retargeters(mock_environment, mocker):
             "isaacsim.core.prims": mocker.MagicMock(),
         },
     )
-    mocker.patch("isaaclab.devices.openxr.openxr_device.XRCore", mock_environment["omni"].kit.xr.core.XRCore)
-    mocker.patch(
-        "isaaclab.devices.openxr.openxr_device.XRPoseValidityFlags",
-        mock_environment["omni"].kit.xr.core.XRPoseValidityFlags,
-    )
-    mock_single_xform = mocker.patch("isaaclab.devices.openxr.openxr_device.SingleXFormPrim")
+    mocker.patch.object(device_mod, "XRCore", mock_environment["omni"].kit.xr.core.XRCore)
+    mocker.patch.object(device_mod, "XRPoseValidityFlags", mock_environment["omni"].kit.xr.core.XRPoseValidityFlags)
+    mock_single_xform = mocker.patch.object(device_mod, "SingleXFormPrim")
 
     # Configure the mock to return a string for prim_path
     mock_instance = mock_single_xform.return_value
     mock_instance.prim_path = "/XRAnchor"
 
     # Mock retargeter classes
-    mocker.patch("isaaclab.devices.openxr.retargeters.Se3AbsRetargeter")
-    mocker.patch("isaaclab.devices.openxr.retargeters.GripperRetargeter")
+    retargeter_mod = importlib.import_module("isaaclab.devices.openxr.retargeters")
+    mocker.patch.object(retargeter_mod, "Se3AbsRetargeter")
+    mocker.patch.object(retargeter_mod, "GripperRetargeter")
 
     # Create the device using the factory
     device = create_teleop_device("test_xr", devices_cfg)

source/isaaclab/test/devices/test_oxr_device.py

@@ -17,6 +17,7 @@ HEADLESS = True
 app_launcher = AppLauncher(headless=HEADLESS)
 simulation_app = app_launcher.app
 
+import importlib
 import numpy as np
 
 import carb
@@ -119,8 +120,9 @@ def mock_xrcore(mocker):
     head_mock.get_virtual_world_pose.return_value = pose_matrix_mock
 
     # Patch the modules
-    mocker.patch("isaaclab.devices.openxr.openxr_device.XRCore", xr_core_mock)
-    mocker.patch("isaaclab.devices.openxr.openxr_device.XRPoseValidityFlags", xr_pose_validity_flags_mock)
+    device_mod = importlib.import_module("isaaclab.devices.openxr.openxr_device")
+    mocker.patch.object(device_mod, "XRCore", xr_core_mock)
+    mocker.patch.object(device_mod, "XRPoseValidityFlags", xr_pose_validity_flags_mock)
 
     return {
         "XRCore": xr_core_mock,

source/isaaclab/test/sensors/test_tiled_camera.py

@@ -1593,10 +1593,15 @@ def test_frame_offset_small_resolution(setup_camera):
     camera_cfg = copy.deepcopy(camera_cfg)
     camera_cfg.height = 80
     camera_cfg.width = 80
+    camera_cfg.offset.pos = (0.0, 0.0, 0.5)
     tiled_camera = TiledCamera(camera_cfg)
     # play sim
     sim.reset()
     # simulate some steps first to make sure objects are settled
+    stage = stage_utils.get_current_stage()
+    for i in range(10):
+        prim = stage.GetPrimAtPath(f"/World/Objects/Obj_{i:02d}")
+        UsdGeom.Gprim(prim).GetOrderedXformOps()[2].Set(Gf.Vec3d(1.0, 1.0, 1.0))
     for i in range(100):
         # step simulation
         sim.step()
@@ -1606,7 +1611,6 @@ def test_frame_offset_small_resolution(setup_camera):
     image_before = tiled_camera.data.output["rgb"].clone() / 255.0
 
     # update scene
-    stage = stage_utils.get_current_stage()
     for i in range(10):
         prim = stage.GetPrimAtPath(f"/World/Objects/Obj_{i:02d}")
         color = Gf.Vec3f(0, 0, 0)
@@ -1621,7 +1625,7 @@ def test_frame_offset_small_resolution(setup_camera):
     image_after = tiled_camera.data.output["rgb"].clone() / 255.0
 
     # check difference is above threshold
-    assert torch.abs(image_after - image_before).mean() > 0.01  # images of same color should be below 0.001
+    assert torch.abs(image_after - image_before).mean() > 0.1  # images of same color should be below 0.01
 
 
 def test_frame_offset_large_resolution(setup_camera):
@@ -1677,16 +1681,17 @@ Helper functions.
 @staticmethod
 def _populate_scene():
     """Add prims to the scene."""
-    # TODO: why does this cause hanging in Isaac Sim 5.0?
-    # # Ground-plane
-    # cfg = sim_utils.GroundPlaneCfg()
-    # cfg.func("/World/defaultGroundPlane", cfg)
+    # Ground-plane
+    cfg = sim_utils.GroundPlaneCfg()
+    cfg.func("/World/defaultGroundPlane", cfg)
     # Lights
     cfg = sim_utils.SphereLightCfg()
     cfg.func("/World/Light/GreySphere", cfg, translation=(4.5, 3.5, 10.0))
     cfg.func("/World/Light/WhiteSphere", cfg, translation=(-4.5, 3.5, 10.0))
     # Random objects
     random.seed(0)
+    np.random.seed(0)
+    torch.manual_seed(0)
     for i in range(10):
         # sample random position
         position = np.random.rand(3) - np.asarray([0.05, 0.05, -1.0])

source/isaaclab/test/sim/test_schemas.py

@@ -109,6 +109,8 @@ def test_modify_properties_on_articulation_instanced_usd(setup_simulation):
     sim, arti_cfg, rigid_cfg, collision_cfg, mass_cfg, joint_cfg = setup_simulation
     # spawn asset to the stage
     asset_usd_file = f"{ISAAC_NUCLEUS_DIR}/Robots/ANYbotics/anymal_c/anymal_c.usd"
+    if "4.5" in ISAAC_NUCLEUS_DIR:
+        asset_usd_file = asset_usd_file.replace("http", "https").replace("production", "staging").replace("4.5", "5.0")
     prim_utils.create_prim("/World/asset_instanced", usd_path=asset_usd_file, translation=(0.0, 0.0, 0.62))
 
     # set properties on the asset and check all properties are set
@@ -132,6 +134,8 @@ def test_modify_properties_on_articulation_usd(setup_simulation):
     sim, arti_cfg, rigid_cfg, collision_cfg, mass_cfg, joint_cfg = setup_simulation
     # spawn asset to the stage
     asset_usd_file = f"{ISAAC_NUCLEUS_DIR}/Robots/FrankaRobotics/FrankaPanda/franka.usd"
+    if "4.5" in ISAAC_NUCLEUS_DIR:
+        asset_usd_file = asset_usd_file.replace("http", "https").replace("production", "staging").replace("4.5", "5.0")
     prim_utils.create_prim("/World/asset", usd_path=asset_usd_file, translation=(0.0, 0.0, 0.62))
 
     # set properties on the asset and check all properties are set

source/isaaclab/test/sim/test_stage_in_memory.py

@@ -20,6 +20,7 @@ import omni.usd
 import pytest
 import usdrt
 from isaacsim.core.cloner import GridCloner
+from isaacsim.core.version import get_version
 
 import isaaclab.sim as sim_utils
 from isaaclab.sim.simulation_context import SimulationCfg, SimulationContext
@@ -48,12 +49,17 @@ Tests
 def test_stage_in_memory_with_shapes(sim):
     """Test spawning of shapes with stage in memory."""
 
+    # skip test if stage in memory is not supported
+    isaac_sim_version = float(".".join(get_version()[2]))
+    if isaac_sim_version < 5:
+        pytest.skip("Stage in memory is not supported in this version of Isaac Sim")
+
     # define parameters
     num_clones = 10
 
     # grab stage in memory and set as current stage via the with statement
     stage_in_memory = sim.get_initial_stage()
-    with stage_utils.use_stage(stage_in_memory):
+    with sim_utils.use_stage(stage_in_memory):
         # create cloned cone stage
         for i in range(num_clones):
             prim_utils.create_prim(f"/World/env_{i}", "Xform", translation=(i, i, 0))
@@ -90,7 +96,7 @@ def test_stage_in_memory_with_shapes(sim):
 
         # verify prims do not exist in context stage
         context_stage = omni.usd.get_context().get_stage()
-        with stage_utils.use_stage(context_stage):
+        with sim_utils.use_stage(context_stage):
             prims = prim_utils.find_matching_prim_paths(prim_path_regex)
             assert len(prims) != num_clones
 
@@ -108,6 +114,11 @@ def test_stage_in_memory_with_shapes(sim):
 def test_stage_in_memory_with_usds(sim):
     """Test spawning of USDs with stage in memory."""
 
+    # skip test if stage in memory is not supported
+    isaac_sim_version = float(".".join(get_version()[2]))
+    if isaac_sim_version < 5:
+        pytest.skip("Stage in memory is not supported in this version of Isaac Sim")
+
     # define parameters
     num_clones = 10
     usd_paths = [
@@ -117,7 +128,7 @@ def test_stage_in_memory_with_usds(sim):
 
     # grab stage in memory and set as current stage via the with statement
     stage_in_memory = sim.get_initial_stage()
-    with stage_utils.use_stage(stage_in_memory):
+    with sim_utils.use_stage(stage_in_memory):
         # create cloned robot stage
         for i in range(num_clones):
             prim_utils.create_prim(f"/World/env_{i}", "Xform", translation=(i, i, 0))
@@ -151,7 +162,7 @@ def test_stage_in_memory_with_usds(sim):
 
         # verify prims do not exist in context stage
         context_stage = omni.usd.get_context().get_stage()
-        with stage_utils.use_stage(context_stage):
+        with sim_utils.use_stage(context_stage):
             prims = prim_utils.find_matching_prim_paths(prim_path_regex)
             assert len(prims) != num_clones
 
@@ -169,13 +180,18 @@ def test_stage_in_memory_with_usds(sim):
 def test_stage_in_memory_with_clone_in_fabric(sim):
     """Test cloning in fabric with stage in memory."""
 
+    # skip test if stage in memory is not supported
+    isaac_sim_version = float(".".join(get_version()[2]))
+    if isaac_sim_version < 5:
+        pytest.skip("Stage in memory is not supported in this version of Isaac Sim")
+
     # define parameters
     usd_path = f"{ISAACLAB_NUCLEUS_DIR}/Robots/ANYbotics/ANYmal-C/anymal_c.usd"
     num_clones = 100
 
     # grab stage in memory and set as current stage via the with statement
     stage_in_memory = sim.get_initial_stage()
-    with stage_utils.use_stage(stage_in_memory):
+    with sim_utils.use_stage(stage_in_memory):
         # set up paths
         base_env_path = "/World/envs"
         source_prim_path = f"{base_env_path}/env_0"
@@ -202,7 +218,7 @@ def test_stage_in_memory_with_clone_in_fabric(sim):
 
         # verify prims do not exist in context stage
         context_stage = omni.usd.get_context().get_stage()
-        with stage_utils.use_stage(context_stage):
+        with sim_utils.use_stage(context_stage):
             prims = prim_utils.find_matching_prim_paths(prim_path_regex)
             assert len(prims) != num_clones
 
@@ -213,7 +229,7 @@ def test_stage_in_memory_with_clone_in_fabric(sim):
     assert not sim_utils.is_current_stage_in_memory()
 
     # verify prims now exist in fabric stage using usdrt apis
-    stage_id = stage_utils.get_current_stage_id()
+    stage_id = sim_utils.get_current_stage_id()
     usdrt_stage = usdrt.Usd.Stage.Attach(stage_id)
     for i in range(num_clones):
         prim = usdrt_stage.GetPrimAtPath(f"/World/envs/env_{i}/Robot")

source/isaaclab/test/sim/test_utils.py

@@ -94,9 +94,11 @@ def test_find_global_fixed_joint_prim():
     prim_utils.create_prim(
         "/World/Franka", usd_path=f"{ISAACLAB_NUCLEUS_DIR}/Robots/FrankaEmika/panda_instanceable.usd"
     )
-    prim_utils.create_prim(
-        "/World/Franka_Isaac", usd_path=f"{ISAAC_NUCLEUS_DIR}/Robots/FrankaRobotics/FrankaPanda/franka.usd"
-    )
+    if "4.5" in ISAAC_NUCLEUS_DIR:
+        franka_usd = f"{ISAAC_NUCLEUS_DIR}/Robots/Franka/franka.usd"
+    else:
+        franka_usd = f"{ISAAC_NUCLEUS_DIR}/Robots/FrankaRobotics/FrankaPanda/franka.usd"
+    prim_utils.create_prim("/World/Franka_Isaac", usd_path=franka_usd)
 
     # test
     assert sim_utils.find_global_fixed_joint_prim("/World/ANYmal") is None

source/isaaclab_tasks/test/benchmarking/test_environments_training.py

@@ -92,7 +92,7 @@ def test_train_environments(workflow, task_spec, config_path, mode, num_gpus, kp
     env_config = utils.get_env_config(env_configs, mode, workflow, task)
 
     # Skip if config not found
-    if not env_config:
+    if env_config is None:
         pytest.skip(f"No config found for task {task} in {mode} mode")
 
     job_name = f"{workflow}:{task}"

source/isaaclab_tasks/test/benchmarking/test_utils.py

@@ -67,7 +67,7 @@ def evaluate_job(workflow, task, env_config, duration):
 
     # evaluate all thresholds from the config
     for threshold_name, threshold_val in thresholds.items():
-        uses_lower_threshold = threshold_name in env_config["lower_thresholds"]
+        uses_lower_threshold = threshold_name in env_config.get("lower_thresholds", {})
         if threshold_name == "duration":
             val = duration
         else:
@@ -150,6 +150,10 @@ def _retrieve_logs(workflow, task):
     """Retrieve training logs."""
     # first grab all log files
     repo_path = os.path.join(carb.tokens.get_tokens_interface().resolve("${app}"), "..")
+    from isaacsim.core.version import get_version
+
+    if int(get_version()[2]) < 5:
+        repo_path = os.path.join(repo_path, "..")
     if workflow == "rl_games":
         log_files_path = os.path.join(repo_path, f"logs/{workflow}/{task}/*/summaries/*")
     else:

source/isaaclab_tasks/test/test_environments.py

@@ -31,6 +31,7 @@ import torch
 import carb
 import omni.usd
 import pytest
+from isaacsim.core.version import get_version
 
 from isaaclab.envs import ManagerBasedRLEnvCfg
 from isaaclab.envs.utils.spaces import sample_space
@@ -59,10 +60,34 @@ def setup_environment():
     return registered_tasks
 
 
+# note, running an env test without stage in memory then
+# running an env test with stage in memory causes IsaacLab to hang.
+# so, here we run all envs with stage in memory first, then run
+# all envs without stage in memory.
+@pytest.mark.order(1)
+@pytest.mark.parametrize("num_envs, device", [(32, "cuda"), (1, "cuda")])
+@pytest.mark.parametrize("task_name", setup_environment())
+def test_environments_with_stage_in_memory(task_name, num_envs, device):
+    # run environments with stage in memory
+    _run_environments(task_name, device, num_envs, num_steps=100, create_stage_in_memory=True)
+
+
+@pytest.mark.order(2)
 @pytest.mark.parametrize("num_envs, device", [(32, "cuda"), (1, "cuda")])
 @pytest.mark.parametrize("task_name", setup_environment())
 def test_environments(task_name, num_envs, device):
+    # run environments without stage in memory
+    _run_environments(task_name, device, num_envs, num_steps=100, create_stage_in_memory=False)
+
+
+def _run_environments(task_name, device, num_envs, num_steps, create_stage_in_memory):
     """Run all environments and check environments return valid signals."""
+
+    # skip test if stage in memory is not supported
+    isaac_sim_version = float(".".join(get_version()[2]))
+    if isaac_sim_version < 5 and create_stage_in_memory:
+        pytest.skip("Stage in memory is not supported in this version of Isaac Sim")
+
     # skip these environments as they cannot be run with 32 environments within reasonable VRAM
     if num_envs == 32 and task_name in [
         "Isaac-Stack-Cube-Franka-IK-Rel-Blueprint-v0",
@@ -76,26 +101,33 @@ def test_environments(task_name, num_envs, device):
     if task_name in ["Isaac-AutoMate-Assembly-Direct-v0", "Isaac-AutoMate-Disassembly-Direct-v0"]:
         return
     # skipping this test for now as it requires torch 2.6 or newer
+
     if task_name == "Isaac-Cartpole-RGB-TheiaTiny-v0":
         return
     # TODO: why is this failing in Isaac Sim 5.0??? but the environment itself can run.
     if task_name == "Isaac-Lift-Teddy-Bear-Franka-IK-Abs-v0":
         return
     print(f">>> Running test for environment: {task_name}")
-    _check_random_actions(task_name, device, num_envs, num_steps=100)
+    _check_random_actions(task_name, device, num_envs, num_steps=100, create_stage_in_memory=create_stage_in_memory)
     print(f">>> Closing environment: {task_name}")
     print("-" * 80)
 
 
-def _check_random_actions(task_name: str, device: str, num_envs: int, num_steps: int = 1000):
+def _check_random_actions(
+    task_name: str, device: str, num_envs: int, num_steps: int = 1000, create_stage_in_memory: bool = False
+):
     """Run random actions and check environments returned signals are valid."""
-    # create a new stage
+
+    if not create_stage_in_memory:
+        # create a new context stage
         omni.usd.get_context().new_stage()
+
     # reset the rtx sensors carb setting to False
     carb.settings.get_settings().set_bool("/isaaclab/render/rtx_sensors", False)
     try:
         # parse configuration
         env_cfg: ManagerBasedRLEnvCfg = parse_env_cfg(task_name, device=device, num_envs=num_envs)
+        env_cfg.sim.create_stage_in_memory = create_stage_in_memory
 
         # skip test if the environment is a multi-agent task
         if hasattr(env_cfg, "possible_agents"):