Daniel Raymond

import hou
import husd.outputprocessor as base
from pxr import Sdf
import pathlib

class UsdFormatOutputProcessor(base.OutputProcessor):
    def __init__(self):
        super().__init__()

    @staticmethod
    def name():
        return 'usdformat'

    @staticmethod
    def displayName():
        return '.USD Format'

    @staticmethod
    def parameters():
        group = hou.ParmTemplateGroup()
        group.append(hou.StringParmTemplate("format", "Format", 1))
        return group.asDialogScript()

    def beginSave(self, config_node, config_overrides, lop_node, t):
        super().beginSave(config_node, config_overrides, lop_node, t)
        self.format = config_node.parm("format").evalAsString()

    def processSavePath(self, asset_path, referencing_layer_path, asset_is_layer):
        obj = pathlib.Path(asset_path)
        if asset_is_layer and obj.suffix == ".usd":
            asset_path = Sdf.Layer.CreateIdentifier(str(obj), {"format": self.format})
            print(".USD Format:", asset_path)
            return asset_path
        return asset_path

################################################################################
# In order to be considered for output processing, this python module
# implements the function that returns a processor object.
#
def usdOutputProcessor():
    return UsdFormatOutputProcessor

from pxr import UsdUtils
node = hou.pwd()
source_input = node.input(0).input(0)  # Skip over immediate layerbreak
layers = list()
for i in reversed(range(source_input.sourceLayerCount())):
    layers.append(source_input.sourceLayer(i))
target_layer = node.editableLayer()
[UsdUtils.StitchLayers(target_layer, layer) for layer in layers]