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USDのインスタンス

ipynbFile usd_instance__USDのインスタンス.ipynb

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from pxr import Usd,UsdGeom,Sdf

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stage = Usd.Stage.Open("D:/Kitchen_set/Kitchen_set_instanced.usd")

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for prim in stage.Traverse():
    if prim.IsInstance():
        # instanceable なPrimを列挙する
        # Primから、InstanceのPrototype（ベース）のPrimを取得する
        protoPrim = prim.GetPrototype()

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# instanceable が指定されたPrimは、
# StageにPrototypePrimとして登録される。
prototypes = stage.GetPrototypes()
print(prototypes[0].IsPrototype())

Success

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True

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canA = stage.GetPrimAtPath('/Kitchen_set/Props_grp/West_grp/TinCanA_1')
canB = stage.GetPrimAtPath('/Kitchen_set/Props_grp/West_grp/TinCanA_2')
# 同じモデルなので、Prototypeは共通
print(canA.GetPrototype())
print(canB.GetPrototype())

Success

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Usd.Prim(</__Prototype_2>)
Usd.Prim(</__Prototype_2>)

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stage = Usd.Stage.CreateInMemory()

primA = stage.DefinePrim("/sampleA")
primA.GetReferences().AddReference('./cube.usd')
primA.SetInstanceable(True)
primB = stage.DefinePrim("/sampleB")
primB.SetInstanceable(True)
primB.GetReferences().AddReference('./cube.usd')

primC = stage.DefinePrim("/sampleC")
primC.GetReferences().AddReference('./cube.usd')

# Instanceの場合はChildはみつからない
print(primB.GetChildren())
# 普通なら見つかる
print(primC.GetChildren())

Success

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[]
[Usd.Prim(</sampleC/cube>)]

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prototype = primA.GetPrototype()

for instance in prototype.GetInstances():
    print(instance)

Success

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Usd.Prim(</sampleA>)
Usd.Prim(</sampleB>)

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stage.GetRootLayer().Export("./instance.usd")

Success

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True

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for i in primB.GetPrototype().GetChildren():
    print(i)

Success

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Usd.Prim(</__Prototype_1/cube>)

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prototypes = stage.GetPrototypes()
prototype = prototypes[0]

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prototype.GetInstances()

Success

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[Usd.Prim(</sampleA>), Usd.Prim(</sampleB>)]

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# InstanceのPrimも GetPrimAtPathで取得が可能
proxy = stage.GetPrimAtPath("/sampleA/cube")
# Proxyの場合、値の追加や変更を使用するとエラーになる
proxy.CreateAttribute('sample',Sdf.ValueTypeNames.String).Set('hoge')

Error

ErrorException Traceback (most recent call last)

in
2 proxy = stage.GetPrimAtPath("/sampleA/cube")
3 # Proxyの場合、値の追加や変更を使用するとエラーになる
----> 4 proxy.CreateAttribute('sample',Sdf.ValueTypeNames.String).Set('hoge')

ErrorException:
Error in 'pxrInternal_v0_21__pxrReserved__::UsdStage::_ValidateEditPrim' at line 1297 in file D:\work\GithubRepo\USD\pxr\usd\usd\stage.cpp : 'Cannot create property spec at path ; authoring to an instance proxy is not allowed.'

In [66]:

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# ProxyからPrototype側でのPathを取得
protoPrim = proxy.GetPrimInPrototype()
protoPrim.CreateAttribute('sample',Sdf.ValueTypeNames.String).Set('hoge')

Error

ErrorException Traceback (most recent call last)

in
1 # ProxyからPrototype側でのPathを取得
2 protoPrim = proxy.GetPrimInPrototype()
----> 3 protoPrim.CreateAttribute('sample',Sdf.ValueTypeNames.String).Set('hoge')

ErrorException:
Error in 'pxrInternal_v0_21__pxrReserved__::UsdStage::_ValidateEditPrim' at line 1290 in file D:\work\GithubRepo\USD\pxr\usd\usd\stage.cpp : 'Cannot create property spec at path ; authoring to an instancing prototype is not allowed.'