Currently there's no way to import attributes for masters. extraAttributesOrNamespaces UsdIn opArg makes attributes appear on instances, it's not always desirable. For example if you want to import lookfiles this way, attributes have to be created on masters instead.
Currently there's no way to import attributes for masters. extraAttributesOrNamespaces UsdIn opArg makes attributes appear on instances, it's not always desirable. For example if you want to import lookfiles this way, attributes have to be created on masters instead.