1

Isaac Sim 5.0.0, Windows 11.

I keep getting the warning to upgrade to the upgrade_prim_semantics_to_labels(prim) function and add_labels function.

[Warning] [isaacsim.core.utils.semantics] Function 'add_update_semantics' uses the deprecated SemanticsAPI. Consider upgrading the semantics with `upgrade_prim_semantics_to_labels(prim)` first and then using `add_labels` instead.

The code below works for the “Parent name” loop. But when it gets to the “Sub Part” loop, I encounter an error on the add_labels function:

Exception has occurred: ErrorException

 	Error in 'pxrInternal_v0_24__pxrReserved__::UsdStage::_SetValueImpl' at line 6703 in file C:\g\169973693\USD\pxr\usd\usd\stage.cpp : 'Empty typeName for </Object_2/applexzy/sp_bruise_001.semantics:labels:class>'

  File "C:\IsaacSim\isaac-sim-standalone-5.0.0-windows-x86_64\extscache\omni.replicator.core-1.12.16+107.3.1.wx64.r.cp311\omni\replicator\core\scripts\functional\modify.py", line 631, in add_semantics     labelsAttr.Set(semantic_value)   File "C:\IsaacSim\isaac-sim-standalone-5.0.0-windows-x86_64\extscache\omni.replicator.core-1.12.16+107.3.1.wx64.r.cp311\omni\replicator\core\scripts\functional\modify.py", line 680, in semantics     add_semantics(prim, semantic_type, semantic_value, mode.lower())   File "C:\IsaacSim\isaac-sim-standalone-5.0.0-windows-x86_64\exts\isaacsim.core.utils\isaacsim\core\utils\semantics.py", line 231, in add_labels     F.modify.semantics(prim, {instance_name: labels}, mode=mode)   File "C:\Users\t\Python\IsaacSim\a01\create_stage_25.py", line 439, in generate_objects     add_labels(child_prim, labels=[sp_name], instance_name="class")   File "C:\Users\t\Python\IsaacSim\a01\create_stage_25.py", line 662, in <module>     constrained_objects_and_limits = generate_objects(stage)                                      ^^^^^^^^^^^^^^^^^^^^^^^ pxr.Tf.ErrorException:  	Error in 'pxrInternal_v0_24__pxrReserved__::UsdStage::_SetValueImpl' at line 6703 in file C:\g\169973693\USD\pxr\usd\usd\stage.cpp : 'Empty typeName for </Object_2/applexzy/sp_bruise_001.semantics:labels:class>

Code:

obj_path = f"/Object_{i}"
obj_prim = stage.DefinePrim(obj_path, "Xform")
xform_api = UsdGeom.XformCommonAPI(obj_prim)
#xform_api.RotationOrderZYX()    
xform_api.SetTranslate((x, y, z))
xform_api.SetRotate(gf_rot_XYZ)

# Add the object and ensure the object prim is a rigid body
obj_prim.GetPayloads().AddPayload(usd_file)
collision_api = UsdPhysics.CollisionAPI.Apply(obj_prim)
mesh_collision_api = UsdPhysics.MeshCollisionAPI.Apply(obj_prim)
mesh_collision_api.GetApproximationAttr().Set(UsdPhysics.Tokens.convexDecomposition)

#Define semantics
#Parent name
for child_prim in Usd.PrimRange(obj_prim):
    if UsdGeom.Mesh(child_prim):
        child_name = str(child_prim.GetName())
        if not child_name.startswith("sp_"):
            part_name = child_name
            #add_update_semantics(obj_prim, part_name)
            #semantic_api = Semantics.SemanticsAPI.Get(obj_prim, "Semantics")
            upgrade_prim_semantics_to_labels(obj_prim, include_descendants=False)
            add_labels(obj_prim, labels=[part_name], instance_name="class")
            break


#Sub Part names
for child_prim in Usd.PrimRange(obj_prim):
    if UsdGeom.Mesh(child_prim):
        child_name = str(child_prim.GetName())
        if child_name.startswith("sp_"):
            sp_name = child_name.rstrip(digits + "_")
            sp_name = sp_name.replace('sp_', '-')
            sp_name = part_name + sp_name
            #add_update_semantics(child_prim, sp_name)
            #semantic_api = Semantics.SemanticsAPI.Get(child_prim, "Semantics")
            upgrade_prim_semantics_to_labels(child_prim, include_descendants=False)
            add_labels(child_prim, labels=[sp_name], instance_name="class")

obj_prim is structured like this

Object_##                XForm   //Want semantics 'class' to parent object
    applexyz             XForm
        apple            Mesh
        sp_bruise_001    Mesh    //Want semantics 'class' to this too

Really have no idea whats going on.

I read somewhere I could add labels to the USD file when I’m converting from obj → USD. if thats an option, that could work. But I’d like that to be option 2.

2

Could you check whether LabelsAPI is applied to the prim before adding labels by updating your code like this:

from pxr import UsdSemantics

# After upgrade_prim_semantics_to_labels(child_prim)
# Check if LabelsAPI is properly applied before adding labels
if child_prim.HasAPI(UsdSemantics.LabelsAPI):
    # LabelsAPI exists, safe to add labels
    add_labels(child_prim, labels=[sp_name], instance_name="class")
else:
    # LabelsAPI not applied, might need to apply it first
    print(f"Warning: LabelsAPI not found on {child_prim.GetPath()}")
3

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