flatten_layer_stack

Quick Reference

How do you merge changes in anonymous layers onto a stage if the layers have unsaved edits? There are multiple approaches but this section shows one way to do it, which is to combine UsdUtilsFlattenLayerStack and UsdUtilsStitchLayers.

The idea is to remove all references to the anonymous layers's identifiers and then merge the layers into the stage until all Prims / Properties are all together on the stage.

C++

std::vector<pxr::SdfLayerHandle> roots;
std::vector<std::string> identifiers;
// ...
pxr::UsdUtilsResolveAssetPathFn anonymous_path_remover =
    [&identifiers](pxr::SdfLayerHandle const &sourceLayer, std::string const &path) {
        if (std::find(std::begin(identifiers), std::end(identifiers), path) != std::end(identifiers)) {
            return std::string {};
        }

        return std::string {path.c_str()};
    };

auto layer = pxr::UsdUtilsFlattenLayerStack(stage, anonymous_path_remover);

for (auto const &root : roots) {
    pxr::UsdUtilsStitchLayers(layer, root);
}

Python

roots = set((layer.GetRootLayer() for layer in (anonymous1, anonymous2)))
layer = UsdUtils.FlattenLayerStack(
    stage,
    resolveAssetPathFn=functools.partial(
        _remove_anonymous_asset_paths,
        identifiers=tuple(root.identifier for root in roots),
    ),
)

for root in roots:
    UsdUtils.StitchLayers(layer, root)

See Also

https://groups.google.com/d/msg/usd-interest/9-AFtWWOgQY/h8jc6vN0AwAJ

https://groups.google.com/d/msg/usd-interest/kV45vxQ9eNY/n8f6lAoSAQAJ