Isaac-Sim Version
6.0.0
5.1.0
5.0.0
4.5.0
4.2.0
4.1.0
4.0.0
4.5.0
2023.1.1
2023.1.0-hotfix.1
Other (please specify):
Operating System
Ubuntu 24.04
Ubuntu 22.04
Ubuntu 20.04
Windows 11
Windows 10
Other (please specify):
GPU Information
- Model: NVIDIA GeForce RTX 4090
- Driver Version: 570.172.08
Topic Description
Detailed Description
Hi all,
I am currently having an issue loading in World_CityTowerDemopack.usd as a scene in Isaac-Sim when I am running it from a stand alone python script (asset can be found here at Downloadable Asset Packs — Omniverse USD under City Tower Demo Assets Pack). I get it to load in correctly if I start up the GUI and navigate like so: /isaac-sim/isaac_sim.sh, then File -> Open -> World_CityTowerDemopack.usd.
How to Reproduce
from isaacsim import SimulationApp
CONFIG = {
"width": 1280,
"height": 720,
"window_width": 3840,
"window_height": 2160,
"headless": True,
"hide_ui": False,
"renderer": "RaytracedLighting",
"display_options": 3286,
}
simulation_app = SimulationApp(launch_config=CONFIG)
from isaacsim.core.utils.extensions import enable_extension
from omni.isaac.core.world import World
import omni.timeline
import omni.usd
omni.usd.get_context().open_stage(
"/your/path/to/CityTowerDemopack/World_CityTowerDemopack.usd"
)
world = World()
simulation_app.set_setting("/app/window/drawMouse", True)
enable_extension("omni.services.livestream.nvcf")
timeline = omni.timeline.get_timeline_interface()
timeline.play()
import time
for i in range(30):
world.step(render=True)
time.sleep(0.1)
print("Done. Check above for errors.")
simulation_app.close()
Error Messages
2026-02-08T16:39:10Z [42,354ms] [Warning] [omni.usd] USD_MDL: in ResolveResource at line 557 of ../../source/plugins/omni.usdMdl/neuray.cpp – module: /isaac-sim/demo_dir/assets/simulation_assets/CityTowerDemopack/Source/context_Boardwalk/rh_Boardwalk/Materials/Concrete_SmoothPanels_uk2iadmew.mdl function: Concrete_SmoothPanels_uk2iadmew(color,texture_2d,float,float,float,color,float,float,texture_2d,float,float,texture_2d,float,bool,texture_2d,float,texture_2d,bool,color,texture_2d,texture_2d,float,bool,texture_2d,float,bool,::base::mono_mode,float,bool,float,color,float,float,float,float,texture_2d,float2,float,float2,float,float,float,texture_2d,float,texture_2d,bool,bool,bool,bool,int,float2,float,float2,float2,float,float2,float,float,bool) parameter: reflectionroughness_texture Unable to resolve MDL resource for: ‘/Z73file_3A/Z1Fisaac_2Dsim/demo_dir/assets/simulation_assets/CityTowerDemopack/Source/context_Boardwalk/rh_Boardwalk/Materials/Concrete_SmoothPanels_uk2iadmew/uk2iadmew_2K_Roughness.jpg’.
2026-02-08T16:39:10Z [42,356ms] [Error] [rtx.mdltranslator.plugin] Texture file referenced in the material parameter defaults wasn’t resolved properly: ‘file:/isaac-sim/demo_dir/assets/simulation_assets/CityTowerDemopack/Source/context_Boardwalk/rh_Boardwalk/Materials/Concrete_SmoothPanels_uk2iadmew/uk2iadmew_2K_Roughness.jpg’
2026-02-08T16:39:10Z [42,365ms] [Error] [rtx.mdltranslator.plugin] Texture file referenced in the material parameter defaults wasn’t resolved properly: ‘file:/isaac-sim/demo_dir/assets/simulation_assets/CityTowerDemopack/Source/context_Boardwalk/rh_Boardwalk/Materials/Concrete_SmoothPanels_uk2iadmew/uk2iadmew_2K_Roughness.jpg’
2026-02-08T16:39:10Z [42,387ms] [Error] [rtx.neuraylib.plugin] [MDLC:COMPILER] 1.0 MDLC comp error: C120 could not find module ‘::materials::American_Beech_bark_Mat’ in module path
2026-02-08T16:39:10Z [42,387ms] [Warning] [rtx.neuraylib.plugin] Loading MdlModule to DB (rtx_scope0) failed: ::materials::American_Beech_bark_Mat
2026-02-08T16:39:10Z [42,387ms] [Warning] [rtx.neuraylib.plugin] Loading transaction committed (this thread). MdlModule is NOT in the DB (rtx_scope0): ::materials::American_Beech_bark_Mat
2026-02-08T16:39:10Z [42,388ms] [Error] [omni.usd] USD_MDL: in LoadModule at line 313 of ../../source/plugins/omni.usdMdl/neuray.cpp – ‘rtx::neuraylib::MdlModuleId’ for ‘materials/American_Beech_bark_Mat.mdl’ is Invalid
2026-02-08T16:39:10Z [42,388ms] [Error] [omni.hydra] Unable to find SdrShaderNode for prim: ‘/__Prototype_17468773430943753807/Looks/American_Beech_bark_Mat/American_Beech_bark_Mat’ with identifier: ‘3389157577962938302<.::materials::American_Beech_bark_Mat::American_Beech_bark_Mat>’.