I have my character in a file. I tried to add a physics particle mesh for the hair but got the error and stack trace below. I then created a stage and referenced the character from the stage and then added the mesh and it worked.
So it looks like it is expecting a certain depth of the character? I notice it says Cannot append child 'ParticleSystem' to path ''. - that is, the path was empty (hit the root of the stage?). Adding the character into a stage on the other hand worked.
My situation is I have a character in its own file, so I am trying to add all the meshes etc to that character. So I probably want the particle system added directly under “/” (or under “/Environment”?) because it should not be a part of the character model that someone else references. There should only be one for the stage? But the exception means I don’t know how to add mesh to my character in its own file.
2023-06-14 02:53:50 [Warning] [omni.usd] Warning: in AppendChild at line 769 of C:\b\w\ca6c508eae419cf8\USD\pxr\usd\sdf\path.cpp -- Cannot append child 'ParticleSystem' to path ''.
2023-06-14 02:53:50 [Warning] [omni.usd]
2023-06-14 02:53:50 [Error] [omni.kit.commands.command] Failed to execute a command: AddParticleClothComponentCommand.
2023-06-14 02:53:50 [Error] [omni.kit.commands.command] File "d:\omniverse\pkg\create-2022.3.3\kit\exts\omni.kit.property.usd\omni\kit\property\usd\prim_path_widget.py", line 111, in <lambda>
2023-06-14 02:53:50 [Error] [omni.kit.commands.command] objects=o, onclick_fn_weak=f
2023-06-14 02:53:50 [Error] [omni.kit.commands.command] File "d:\omniverse\pkg\create-2022.3.3\kit\exts\omni.kit.property.usd\omni\kit\property\usd\prim_path_widget.py", line 185, in payload_wrapper
2023-06-14 02:53:50 [Error] [omni.kit.commands.command] onclick_fn(payload=payload)
2023-06-14 02:53:50 [Error] [omni.kit.commands.command] File "d:\omniverse\pkg\create-2022.3.3\kit\extsphysics\omni.kit.property.physx\omni\kit\property\physx\widgets.py", line 163, in add_component
2023-06-14 02:53:50 [Error] [omni.kit.commands.command] execute("AddPhysicsComponent", usd_prim=prim, component=component.name)
2023-06-14 02:53:50 [Error] [omni.kit.commands.command] File "d:\omniverse\pkg\create-2022.3.3\kit\extscore\omni.kit.commands\omni\kit\commands\command.py", line 459, in execute
2023-06-14 02:53:50 [Error] [omni.kit.commands.command] result = omni.kit.undo.execute(command, name, kwargs)
2023-06-14 02:53:50 [Error] [omni.kit.commands.command] File "d:\omniverse\pkg\create-2022.3.3\kit\extscore\omni.kit.commands\omni\kit\undo\undo.py", line 77, in execute
2023-06-14 02:53:50 [Error] [omni.kit.commands.command] result = _execute(command, name, level, history_key)
2023-06-14 02:53:50 [Error] [omni.kit.commands.command] File "d:\omniverse\pkg\create-2022.3.3\kit\extscore\omni.kit.commands\omni\kit\undo\undo.py", line 415, in _execute
2023-06-14 02:53:50 [Error] [omni.kit.commands.command] result = command.do()
2023-06-14 02:53:50 [Error] [omni.kit.commands.command] File "d:\omniverse\pkg\create-2022.3.3\kit\extsphysics\omni.physx.commands-104.2.4-5.1\omni\physxcommands\__init__.py", line 1240, in do
2023-06-14 02:53:50 [Error] [omni.kit.commands.command] execute("AddParticleClothComponentCommand", prim_path=self._usd_prim.GetPath())
2023-06-14 02:53:50 [Error] [omni.kit.commands.command] File "d:\omniverse\pkg\create-2022.3.3\kit\extscore\omni.kit.commands\omni\kit\commands\command.py", line 459, in execute
2023-06-14 02:53:50 [Error] [omni.kit.commands.command] result = omni.kit.undo.execute(command, name, kwargs)
2023-06-14 02:53:50 [Error] [omni.kit.commands.command] [...skipped...]
2023-06-14 02:53:50 [Error] [omni.kit.commands.command] File "d:\omniverse\pkg\create-2022.3.3\kit\extscore\omni.kit.commands\omni\kit\undo\undo.py", line 77, in execute
2023-06-14 02:53:50 [Error] [omni.kit.commands.command] result = _execute(command, name, level, history_key)
2023-06-14 02:53:50 [Error] [omni.kit.commands.command] File "d:\omniverse\pkg\create-2022.3.3\kit\extscore\omni.kit.commands\omni\kit\undo\undo.py", line 454, in _execute
2023-06-14 02:53:50 [Error] [omni.kit.commands.command] raise error
2023-06-14 02:53:50 [Error] [omni.kit.commands.command] File "d:\omniverse\pkg\create-2022.3.3\kit\extscore\omni.kit.commands\omni\kit\undo\undo.py", line 415, in _execute
2023-06-14 02:53:50 [Error] [omni.kit.commands.command] result = command.do()
2023-06-14 02:53:50 [Error] [omni.kit.commands.command] File "d:\omniverse\pkg\create-2022.3.3\kit\extsphysics\omni.physx.commands-104.2.4-5.1\omni\physxcommands\__init__.py", line 2117, in do
2023-06-14 02:53:50 [Error] [omni.kit.commands.command] particle_system = particleUtils.get_default_particle_system(self._stage)
2023-06-14 02:53:50 [Error] [omni.kit.commands.command] File "d:\omniverse\pkg\create-2022.3.3\kit\extsphysics\omni.physx-104.2.4-5.1\omni\physx\scripts\particleUtils.py", line 42, in get_default_particle_system
2023-06-14 02:53:50 [Error] [omni.kit.commands.command] omni.usd.get_stage_next_free_path(stage, str(get_default_particle_system_path(stage)), True)
2023-06-14 02:53:50 [Error] [omni.kit.commands.command] File "d:\omniverse\pkg\create-2022.3.3\kit\extscore\omni.usd\omni\usd\_impl\utils.py", line 944, in get_stage_next_free_path
2023-06-14 02:53:50 [Error] [omni.kit.commands.command] raise ValueError(f"{path} is not a valid path")
2023-06-14 02:53:50 [Error] [omni.kit.commands.command]
2023-06-14 02:53:50 [Error] [omni.kit.commands.command] <class 'ValueError'> is not a valid path