layer.unassign_layer - support batching #4474

src/blenderbim/blenderbim/bim/module/layer/operator.py

@@ -176,7 +176,10 @@ class UnassignPresentationLayer(bpy.types.Operator):
         ifcopenshell.api.run(
             "layer.unassign_layer",
             self.file,
-            **{"item": self.file.by_id(item.BIMMeshProperties.ifc_definition_id), "layer": self.file.by_id(self.layer)}
+            **{
+                "items": [self.file.by_id(item.BIMMeshProperties.ifc_definition_id)],
+                "layer": self.file.by_id(self.layer),
+            }
         )
         return {"FINISHED"}
 

src/ifcopenshell-python/ifcopenshell/api/layer/unassign_layer.py

@@ -16,16 +16,23 @@
 # You should have received a copy of the GNU Lesser General Public License
 # along with IfcOpenShell.  If not, see <http://www.gnu.org/licenses/>.
 
+import ifcopenshell
+import ifcopenshell.util.element
+
 
 class Usecase:
-    def __init__(self, file, item=None, layer=None):
-        """Unassigns an item from a layer
+    def __init__(
+        self, file: ifcopenshell.file, items: list[ifcopenshell.entity_instance], layer: ifcopenshell.entity_instance
+    ):
+        """Unassigns representation items from a layer
 
         If the representation item isn't assigned to the layer, nothing will
         happen.
+        If after unassignment layer won't have any assigned items it will be
+        removed to keep IFC valid.
 
-        :param item: An IfcRepresentationItem element to unassign
-        :type item: ifcopenshell.entity_instance.entity_instance
+        :param items: A list IfcRepresentationItem elements to unassign
+        :type items: list[ifcopenshell.entity_instance.entity_instance]
         :param layer: The IfcPresentationLayerAssignment to unassign from
         :type layer: ifcopenshell.entity_instance.entity_instance
         :return: None
@@ -57,15 +64,24 @@ class Usecase:
             ifcopenshell.api.run("layer.assign_layer", model, items=[representation.Items[0]], layer=layer)
 
             # Let's undo it!
-            ifcopenshell.api.run("layer.unassign_layer", model, item=representation.Items[0], layer=layer)
+            ifcopenshell.api.run("layer.unassign_layer", model, items=[representation.Items[0]], layer=layer)
         """
         self.file = file
         self.settings = {
-            "item": item,
+            "items": items,
             "layer": layer,
         }
 
     def execute(self):
-        assigned_items = set(self.settings["layer"].AssignedItems) or set()
-        assigned_items.remove(self.settings["item"])
-        self.settings["layer"].AssignedItems = list(assigned_items)
+        layer = self.settings["layer"]
+        assigned_items = set(layer.AssignedItems) or set()
+        items = set(self.settings["items"])
+        if not items.issubset(assigned_items):
+            return
+        assigned_items = list(assigned_items - items)
+
+        # keep IFC valid in case if there are no items left
+        if assigned_items:
+            layer.AssignedItems = assigned_items
+        else:
+            self.file.remove(layer)

src/ifcopenshell-python/test/api/layer/test_unassign_layer.py

@@ -0,0 +1,39 @@
+# IfcOpenShell - IFC toolkit and geometry engine
+# Copyright (C) 2022 Dion Moult <dion@thinkmoult.com>
+#
+# This file is part of IfcOpenShell.
+#
+# IfcOpenShell is free software: you can redistribute it and/or modify
+# it under the terms of the GNU Lesser General Public License as published by
+# the Free Software Foundation, either version 3 of the License, or
+# (at your option) any later version.
+#
+# IfcOpenShell is distributed in the hope that it will be useful,
+# but WITHOUT ANY WARRANTY; without even the implied warranty of
+# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+# GNU Lesser General Public License for more details.
+#
+# You should have received a copy of the GNU Lesser General Public License
+# along with IfcOpenShell.  If not, see <http://www.gnu.org/licenses/>.
+
+import test.bootstrap
+import ifcopenshell.api
+
+
+class TestUnassignLayer(test.bootstrap.IFC4):
+    def test_unassign_layer_from_items(self):
+        items = [self.file.createIfcExtrudedAreaSolid() for i in range(3)]
+        layer = self.file.createIfcPresentationLayerAssignment()
+
+        ifcopenshell.api.run("layer.assign_layer", self.file, items=items, layer=layer)
+        ifcopenshell.api.run("layer.unassign_layer", self.file, items=items[2:], layer=layer)
+        assert len(layer.AssignedItems) == 2
+        assert set(layer.AssignedItems) == set(items[:2])
+
+    def test_remove_layer_if_all_items_are_unassigned(self):
+        items = [self.file.createIfcExtrudedAreaSolid() for i in range(3)]
+        layer = self.file.createIfcPresentationLayerAssignment()
+
+        ifcopenshell.api.run("layer.assign_layer", self.file, items=items, layer=layer)
+        ifcopenshell.api.run("layer.unassign_layer", self.file, items=items, layer=layer)
+        assert not self.file.by_type("IfcPresentationLayerAssignment")