Write group content metadata for ufp export

CURA-6915

plugins/UFPWriter/UFPWriter.py

@@ -1,7 +1,7 @@
 # Copyright (c) 2020 Ultimaker B.V.
 # Cura is released under the terms of the LGPLv3 or higher.
 
-from typing import cast
+from typing import cast, List, Dict
 
 from Charon.VirtualFile import VirtualFile  # To open UFP files.
 from Charon.OpenMode import OpenMode  # To indicate that we want to write to UFP files.
@@ -13,6 +13,7 @@ from UM.MimeTypeDatabase import MimeTypeDatabase, MimeType
 from UM.PluginRegistry import PluginRegistry  # To get the g-code writer.
 from PyQt5.QtCore import QBuffer
 
+from UM.Scene.SceneNode import SceneNode
 from cura.CuraApplication import CuraApplication
 from cura.Snapshot import Snapshot
 from cura.Utils.Threading import call_on_qt_thread
@@ -68,7 +69,8 @@ class UFPWriter(MeshWriter):
             return False
         gcode = archive.getStream("/3D/model.gcode")
         gcode.write(gcode_textio.getvalue().encode("UTF-8"))
-        archive.addRelation(virtual_path = "/3D/model.gcode", relation_type = "http://schemas.ultimaker.org/package/2018/relationships/gcode")
+        archive.addRelation(virtual_path="/3D/model.gcode",
+                            relation_type="http://schemas.ultimaker.org/package/2018/relationships/gcode")
 
         self._createSnapshot()
 
@@ -83,7 +85,9 @@ class UFPWriter(MeshWriter):
             thumbnail_image.save(thumbnail_buffer, "PNG")
 
             thumbnail.write(thumbnail_buffer.data())
-            archive.addRelation(virtual_path = "/Metadata/thumbnail.png", relation_type = "http://schemas.openxmlformats.org/package/2006/relationships/metadata/thumbnail", origin = "/3D/model.gcode")
+            archive.addRelation(virtual_path="/Metadata/thumbnail.png",
+                                relation_type="http://schemas.openxmlformats.org/package/2006/relationships/metadata/thumbnail",
+                                origin="/3D/model.gcode")
         else:
             Logger.log("d", "Thumbnail not created, cannot save it")
 
@@ -118,7 +122,8 @@ class UFPWriter(MeshWriter):
             material_root_id = material.getMetaDataEntry("base_file")
             material_root_query = container_registry.findContainers(id=material_root_id)
             if not material_root_query:
-                Logger.log("e", "Cannot find material container with root id {root_id}".format(root_id = material_root_id))
+                Logger.log("e",
+                           "Cannot find material container with root id {root_id}".format(root_id=material_root_id))
                 return False
             material_container = material_root_query[0]
 
@@ -151,11 +156,30 @@ class UFPWriter(MeshWriter):
 
         To retrieve, use: `archive.getMetadata(METADATA_OBJECTS_PATH)`
         """
+
         objects_model = CuraApplication.getInstance().getObjectsModel()
-        object_metas = [{"name": item["name"]}
-                        for item in objects_model.items
-                        if item["node"].getMeshData() is not None and not item["node"].callDecoration("isNonPrintingMesh")
-                        ]
+        object_metas = []
+
+        for item in objects_model.items:
+            object_metas = object_metas + UFPWriter._getObjectMetas(item["node"])
 
         data = {METADATA_OBJECTS_PATH: object_metas}
         archive.setMetadata(data)
+
+    @staticmethod
+    def _getObjectMetas(node: SceneNode) -> List[Dict]:
+        """Get object metadata to write for a Node.
+
+        :return: List of object metadata dictionaries.
+                 Might contain > 1 element in case of a group node.
+                 Might be empty in case of nonPrintingMesh
+        """
+
+        nodes = [node]
+        if node.callDecoration("isGroup"):
+            nodes = nodes + node.getAllChildren()  # all descendants
+
+        return [{"name": item.getName()}
+                for item in nodes
+                if item.getMeshData() is not None and not item.callDecoration("isNonPrintingMesh")
+                ]