has that type been defined as a TfType?

[huangbinbin48070]

i have load my usd schema and registe it as well as use it to set attributes defined in .usda file
but it can't work with Usd.SchemaRegistry().IsMultipleApplyAPISchema

run this pytho code snippt in my usd schema extention

from pxr import Usd ,Tf
import PhysicsSchema
print(1)
print(PhysicsSchema.DeformableBodyAPI.__name__)
print(2)
print(Tf.Type.FindByName("PhysicsSchemaDeformableBodyAPI"))
print(3)
Usd.SchemaRegistry().IsMultipleApplyAPISchema(PhysicsSchema.DeformableBodyAPI) 
print(4)

output :

1
DeformableBodyAPI
2
Tf.Type.FindByName('PhysicsSchemaDeformableBodyAPI')
3
2025-12-23T10:07:53Z [908,617ms] [Error] [carb.scripting-python.plugin] TypeError: cannot convert <class 'PhysicsSchema.DeformableBodyAPI'> to TfType; has that type been defined as a TfType?

At:
  c:/users/cnf202~1/appdata/local/temp/xuz0.0/script_1766484473.py(8): <module>
  c:/users/cnf2025581067/source/repos/isaacsim/_build/windows-x86_64/release/extscache/omni.kit.window.script_editor-2.0.1+69cbf6ad/omni/kit/window/script_editor/script_editor_widget.py(154): _execute_script_async
  c:\users\cnf2025581067\source\repos\isaacsim\_build\windows-x86_64\release\kit\python\Lib\asyncio\events.py(84): _run
  c:\users\cnf2025581067\source\repos\isaacsim\_build\windows-x86_64\release\kit\python\Lib\asyncio\base_events.py(1936): _run_once
  c:/users/cnf2025581067/source/repos/isaacsim/_build/windows-x86_64/release/kit/extscore/omni.kit.async_engine/omni/kit/async_engine/async_engine.py(228): run_once
  c:/users/cnf2025581067/source/repos/isaacsim/_build/windows-x86_64/release/kit/extscore/omni.kit.async_engine/omni/kit/async_engine/async_engine.py(296): <lambda>

I googled this log but found no results
Has anyone encountered this problem?

[michaellin6]

Hi @huangbinbin48070, thank you for posting your question. This USD API is used to check whether a registered schema has the property that can be applied with other API schemas. Examples of how this is used is as follows:

registry = Usd.SchemaRegistry()

# Single-apply API schemas (can only be applied once per prim)
print("Single-Apply API Schemas:")
print(f"MaterialBindingAPI: {registry.IsMultipleApplyAPISchema('UsdShadeMaterialBindingAPI')}")  # False
print(f"PhysicsRigidBodyAPI: {registry.IsMultipleApplyAPISchema('PhysicsRigidBodyAPI')}")  # False
print(f"ModelAPI: {registry.IsMultipleApplyAPISchema('UsdModelAPI')}")  # False

# Multiple-apply API schemas (can be applied multiple times with different instance names)
print("\nMultiple-Apply API Schemas:")
print(f"CollectionAPI: {registry.IsMultipleApplyAPISchema('UsdCollectionAPI')}")  # False
print(f"PhysicsLimitAPI: {registry.IsMultipleApplyAPISchema('PhysicsLimitAPI')}")  # True
print(f"PhysicsDriveAPI: {registry.IsMultipleApplyAPISchema('PhysicsDriveAPI')}")  # True

So you can use it after you have registered your custom schema to check whether it has that property. Does that answer your question?

[huangbinbin48070]

Hi @huangbinbin48070, thank you for posting your question. This USD API is used to check whether a registered schema has the property that can be applied with other API schemas. Examples of how this is used is as follows:

registry = Usd.SchemaRegistry()

# Single-apply API schemas (can only be applied once per prim)
print("Single-Apply API Schemas:")
print(f"MaterialBindingAPI: {registry.IsMultipleApplyAPISchema('UsdShadeMaterialBindingAPI')}")  # False
print(f"PhysicsRigidBodyAPI: {registry.IsMultipleApplyAPISchema('PhysicsRigidBodyAPI')}")  # False
print(f"ModelAPI: {registry.IsMultipleApplyAPISchema('UsdModelAPI')}")  # False

# Multiple-apply API schemas (can be applied multiple times with different instance names)
print("\nMultiple-Apply API Schemas:")
print(f"CollectionAPI: {registry.IsMultipleApplyAPISchema('UsdCollectionAPI')}")  # False
print(f"PhysicsLimitAPI: {registry.IsMultipleApplyAPISchema('PhysicsLimitAPI')}")  # True
print(f"PhysicsDriveAPI: {registry.IsMultipleApplyAPISchema('PhysicsDriveAPI')}")  # True

So you can use it after you have registered your custom schema to check whether it has that property. Does that answer your question?

thank you for patient answer

i have registred my usd schema when plugin loaded

import os,sys

from pxr import Plug


def _register_plugin_path(path):
    print("regeiste usd schema resource :" , path)
    result = Plug.Registry().RegisterPlugins(path)
    if not result:
        import carb

        carb.log_error(f"No plugins found at path {path}")


def _register_plugins(ext_path: str):
    plugins_dir = os.path.join(ext_path, "usd","plugins")
    _register_plugin_path(os.path.join(plugins_dir, "PhysicsSchema", "resources"))


ext_path = os.path.dirname(os.path.dirname(os.path.dirname(os.path.abspath(__file__))))
_register_plugins(ext_path)

even it can applied prim , and set/get prims attributes
but once i usde Usd.SchemaRegistry().IsMultipleApplyAPISchema(PhysicsSchema.DeformableBodyAPI)
it don't return true or false , just throw an exception

for more infomations:
.usda

#usda 1.0
(
    """ Custom RBS Physics Schema    """
    subLayers = [
        @usd/schema.usda@
    ]
)

over "GLOBAL" (
    customData = {
        string libraryName       = "physicsSchema"
        string libraryPath       = "."
    }
)
{
}

# This defines Cloth Physics Schema API
class "ClothPhysicsAPI" (
    doc = """A API Schema for Cloth simulation"""
    inherits = </APISchemaBase>
    customData = {
        token apiSchemaType = "singleApply"
    }
)
{
    float physics:youngsModulus (
        doc = "Float value denoting Young's modulus"
        customData = {
            string apiName= "youngsModulus"
        }
    )

    float physics:possionRatio (
        doc = "Float value denoting Possion's ratio"
        customData = {
            string apiName = "possionRatio"
        }
    )

    float physics:thickness (
        doc = "Float value denoting the thickness of cloth"
        customData = {
            string apiName = "thickness"
        }
    )

    float physics:blendingStiffness (
        doc = "Float value denoting the blending stiffness of cloth"
        customData = {
            string apiName = "blendingStiffness"
        }
    )
}


class "DeformableBodyAPI" (
    doc = "A singleApply schema for deformable/soft body simulation"
    inherits = </APISchemaBase>
    customData = {
        token apiSchemaType = "singleApply"
    }
)
{
    float deform:youngsModulus (
        doc = "Float value denoting Young's modulus"
        customData = {
            string apiName= "youngsModulus"
        }
    )

    float deform:possionRatio (
        doc = "Float value denoting Possion's ratio"
        customData = {
            string apiName = "possionRatio"
        }
    )
}

class "RbsJointStateAPI" (
    doc = "A singleApply schema for joint state"
    inherits = </APISchemaBase>
    customData = {
        token apiSchemaType = "singleApply"
    }
)
{
    float joint:angular (
        doc = "float value denoting the state of the joint"
        customData = {
            string apiName = "angular"
        }
    )

    float joint:velocity (
        doc = "float value denoting the velocity of the joint"
        customData = {
            string apiName = "velocity"
        }
    )
}

add set/get test :

import omni.usd
import PhysicsSchema
from pxr import Usd ,Tf
import PhysicsSchema
print(0)
stage = omni.usd.get_context().get_stage() 
prim = stage.GetPrimAtPath("/World/Cube")
PhysicsSchema.DeformableBodyAPI.Apply(prim)
deform_api = PhysicsSchema.DeformableBodyAPI(prim) 
attr = deform_api.GetPossionRatioAttr()
attr.Set(99)
for attr in prim.GetAttributes():
    if attr.GetName() == "deform:possionRatio" :
        print(
            f"type={attr.GetTypeName()}, "
            f"value={attr.Get()}"
        )
        
print(1)
print(PhysicsSchema.DeformableBodyAPI.__name__)
print(2)
print(Tf.Type.FindByName("PhysicsSchemaDeformableBodyAPI"))
print(3)
Usd.SchemaRegistry().IsMultipleApplyAPISchema(PhysicsSchema.DeformableBodyAPI) 
print(4)

output:

0
type=float, value=99.0
1
DeformableBodyAPI
2
Tf.Type.FindByName('PhysicsSchemaDeformableBodyAPI')
3
2025-12-24T01:31:22Z [54,134,787ms] [Error] [carb.scripting-python.plugin] TypeError: cannot convert <class 'PhysicsSchema.DeformableBodyAPI'> to TfType; has that type been defined as a TfType?

At:
  c:/users/cnf202~1/appdata/local/temp/x8gg.0/script_1766539882.py(24): <module>
  c:/users/cnf2025581067/source/repos/isaacsim/_build/windows-x86_64/release/extscache/omni.kit.window.script_editor-2.0.1+69cbf6ad/omni/kit/window/script_editor/script_editor_widget.py(154): _execute_script_async
  c:\users\cnf2025581067\source\repos\isaacsim\_build\windows-x86_64\release\kit\python\Lib\asyncio\events.py(84): _run
  c:\users\cnf2025581067\source\repos\isaacsim\_build\windows-x86_64\release\kit\python\Lib\asyncio\base_events.py(1936): _run_once
  c:/users/cnf2025581067/source/repos/isaacsim/_build/windows-x86_64/release/kit/extscore/omni.kit.async_engine/omni/kit/async_engine/async_engine.py(228): run_once
  c:/users/cnf2025581067/source/repos/isaacsim/_build/windows-x86_64/release/kit/extscore/omni.kit.async_engine/omni/kit/async_engine/async_engine.py(296): <lambda>

[huangbinbin48070]

IsMultipleApplyAPISchema should work with string type paramters as well as schema class type.
onece passed custom schema class type , will throw an exception

[huangbinbin48070]

when i build my usd schema , linker using usd_tf.lib in _build\target-deps\usd\release , this dir link to /c/packman-repo/chk/usd.py311.windows-x86_64.stock.release/0.24.05.kit.7-gl.16400+05f48f24

when i load usd plugin ,runtime usd_tf.dll in _build\windows-x86_64\release\extscache\omni.usd.libs-1.0.1+69cbf6ad.wx64.r.cp311 ,this dir link to /c/Users/CNF2025581067/AppData/Local/ov/data/exts/v2/omni.usd.libs-c0d53e4ebe7b5470

but even i copy and covered , this probolm still exists .

[huangbinbin48070]

remove compiler option /Zc:inline

[michaellin6]

Can you try:
Usd.SchemaRegistry().IsMultipleApplyAPISchema(PhysicsSchema.DeformableBodyAPI.__name__)? I have mostly used the API signature with a string input corresponding to the name of the API.

[huangbinbin48070]

Usd.SchemaRegistry().IsMultipleApplyAPISchema(PhysicsSchema.DeformableBodyAPI.__name__) works , passing the type is also works after removing the msvc compilation option /Zc:inline,