batch_namespace_edit

Quick Explanation

Sdf Layers can use change blocks to prevent notifications from being sent whenever edits to a layer occur. But for simple namespace changes, Sdf Layers have another technique that can be used to make many changes at once, as long as you know every change that you need to make, up-front. It's called a BatchNamespaceEdit.

Quick note: The code used in this concept was taken straight from USD's unittests. So this section is mostly just to make an existing feature more visible, since you normally would have to dig to find out this information.

C++

edit.Add(
    pxr::SdfNamespaceEdit{
        pxr::SdfPath{"/C"},
        pxr::SdfPath{"/D"},
    },
);  // Prim renames
edit.Add(
    pxr::SdfNamespaceEdit{
        pxr::SdfPath{"/G"},
        pxr::SdfPath{"/E/G"},
    },
);  // Prim reparents
edit.Add(
    pxr::SdfNamespaceEdit{
        pxr::SdfPath{"/I"},
        pxr::SdfPath{"/E/H"},
    },
);  // Prim reparent/rename
edit.Add(
    pxr::SdfNamespaceEdit{
        pxr::SdfPath{"/L/J/K"},
        pxr::SdfPath{"/K"},
    },
);  // Prim reparent from under a reparented prim
edit.Add(
    pxr::SdfNamespaceEdit{
        pxr::SdfPath{"/X"},
        pxr::SdfPath::EmptyPath(),
    },
);  // Prim remove
edit.Add(
    pxr::SdfNamespaceEdit{
        pxr::SdfPath{"/E"},
        pxr::SdfPath::EmptyPath(),
    },
);  // Prim with descendants remove

edit.Add(
    pxr::SdfNamespaceEdit{
        pxr::SdfPath{"/P.c"},
        pxr::SdfPath{"/P.d"},
    },
);  // Prim property renames
edit.Add(
    pxr::SdfNamespaceEdit{
        pxr::SdfPath{"/P.g"},
        pxr::SdfPath{"/Q.g"},
    },
);  // Prim property reparents

edit.Add(
    pxr::SdfNamespaceEdit{
        pxr::SdfPath{"/S"},
        pxr::SdfPath{"/T"},
    },
);  // Rename prim used in targets


edit.Add(
    pxr::SdfNamespaceEdit{
        pxr::SdfPath{"/V{v=one}U"},
        pxr::SdfPath{"/V{v=two}W/U"},
    },
);  // Variant prim reparent/rename
edit.Add(
    pxr::SdfNamespaceEdit{
        pxr::SdfPath{"/V{v=two}W"},
        pxr::SdfPath::EmptyPath(),
    },
);  // Variant prim remove
edit.Add(
    pxr::SdfNamespaceEdit{
        pxr::SdfPath{"/V{v=one}.u"},
        pxr::SdfPath{"/V{v=two}.u"},
    },
);  // Variant property reparent/rename
edit.Add(
    pxr::SdfNamespaceEdit{
        pxr::SdfPath{"/V{v=two}.w"},
        pxr::SdfPath::EmptyPath(),
    },
);  // Variant property remove

C++ - Checking if an apply will work

    std::cout << std::boolalpha;
    auto result = layer->CanApply(edit);
    std::cout << "Will applying this layer fail? " << (result == pxr::SdfNamespaceEditDetail::Result::Error) << '\n';
    assert(layer->Apply(edit) && "The edit failed");

Python

edit.Add("/C", "/D")  # Prim renames
edit.Add("/G", "/E/G")  # Prim reparents
edit.Add("/I", "/E/H")  # Prim reparent/rename
edit.Add("/L/J/K", "/K")  # Prim reparent from under a reparented prim
edit.Add("/X", Sdf.Path.emptyPath)  # Prim remove
edit.Add("/E", Sdf.Path.emptyPath)  # Prim with descendants remove

edit.Add("/P.c", "/P.d")  # Prim property renames
edit.Add("/P.g", "/Q.g")  # Prim property reparents

edit.Add("/S", "/T")  # Rename prim used in targets

edit.Add("/V{v=one}U", "/V{v=two}W/U")  # Variant prim reparent/rename
edit.Add("/V{v=two}W", Sdf.Path.emptyPath)  # Variant prim remove
edit.Add("/V{v=one}.u", "/V{v=two}.u")  # Variant property reparent/rename
edit.Add("/V{v=two}.w", Sdf.Path.emptyPath)  # Variant property remove

Python - Checking if an apply will work

print('Will applying this layer fail?', not layer.CanApply(edit))
# or, you can apply and test if the apply failed
assert layer.Apply(edit)

See Also

https://github.com/PixarAnimationStudios/USD/blob/master/pxr/usd/lib/sdf/testenv/testSdfBatchNamespaceEdit.py https://graphics.pixar.com/usd/docs/api/class_sdf_layer.html#a4c1b4761140c863aa0e6a2ef6fffe243