Implement support for managing nest hosts and components.

src/blenderbim/blenderbim/bim/__init__.py

@@ -44,6 +44,7 @@ modules = {
     "spatial": None,
     "void": None,
     "aggregate": None,
+    "nest": None,
     "geometry": None,
     "fm": None,
     "resource": None,

src/blenderbim/blenderbim/bim/module/aggregate/__init__.py

@@ -20,14 +20,14 @@ import bpy
 from . import ui, prop, operator
 
 classes = (
-    operator.BIM_OT_assign_object,
-    operator.BIM_OT_unassign_object,
-    operator.BIM_OT_enable_editing_aggregate,
-    operator.BIM_OT_disable_editing_aggregate,
     operator.BIM_OT_add_aggregate,
-    operator.BIM_OT_select_parts,
-    operator.BIM_OT_select_aggregate,
     operator.BIM_OT_add_part_to_object,
+    operator.BIM_OT_assign_object,
+    operator.BIM_OT_disable_editing_aggregate,
+    operator.BIM_OT_enable_editing_aggregate,
+    operator.BIM_OT_select_aggregate,
+    operator.BIM_OT_select_parts,
+    operator.BIM_OT_unassign_object,
     prop.BIMObjectAggregateProperties,
     ui.BIM_PT_aggregate,
 )

src/blenderbim/blenderbim/bim/module/aggregate/data.py

@@ -35,7 +35,7 @@ class AggregateData:
             "has_relating_object": cls.has_relating_object(),
             "relating_object_label": cls.get_relating_object_label(),
             "has_related_objects": cls.has_related_objects(),
-            "related_objects_amount": cls.get_related_objects_amount(),
+            "total_parts": cls.total_parts(),
             "ifc_class": cls.ifc_class(),
         }
         cls.is_loaded = True
@@ -59,7 +59,7 @@ class AggregateData:
         return ifcopenshell.util.element.get_parts(tool.Ifc.get_entity(bpy.context.active_object))
 
     @classmethod
-    def get_related_objects_amount(cls):
+    def total_parts(cls):
         parts = cls.get_related_objects()
         return len(parts) if parts else 0
 

src/blenderbim/blenderbim/bim/module/aggregate/ui.py

@@ -72,8 +72,14 @@ class BIM_PT_aggregate(Panel):
                 row.operator("bim.add_aggregate", icon="ADD", text="")
 
         row = layout.row(align=True)
-        parts = AggregateData.data["related_objects_amount"]
-        row.label(text=f"{parts or 'No'} Part{'s' if parts > 1 else ''}", icon="TRIA_DOWN")
+        total_parts = AggregateData.data["total_parts"]
+        if total_parts == 0:
+            row.label(text="No Parts", icon="TRIA_DOWN")
+        elif total_parts == 1:
+            row.label(text="1 Part", icon="TRIA_DOWN")
+        else:
+            row.label(text=f"{total_parts} Parts", icon="TRIA_DOWN")
+
         if AggregateData.data["has_related_objects"]:
             op = row.operator("bim.select_parts", icon="RESTRICT_SELECT_OFF", text="")
             op.obj = context.active_object.name

src/blenderbim/blenderbim/bim/module/nest/__init__.py

@@ -0,0 +1,39 @@
+# BlenderBIM Add-on - OpenBIM Blender Add-on
+# Copyright (C) 2023 Dion Moult <dion@thinkmoult.com>
+#
+# This file is part of BlenderBIM Add-on.
+#
+# BlenderBIM Add-on is free software: you can redistribute it and/or modify
+# it under the terms of the GNU General Public License as published by
+# the Free Software Foundation, either version 3 of the License, or
+# (at your option) any later version.
+#
+# BlenderBIM Add-on 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 General Public License for more details.
+#
+# You should have received a copy of the GNU General Public License
+# along with BlenderBIM Add-on.  If not, see <http://www.gnu.org/licenses/>.
+
+import bpy
+from . import ui, prop, operator
+
+classes = (
+    operator.BIM_OT_assign_object,
+    operator.BIM_OT_disable_editing_nest,
+    operator.BIM_OT_enable_editing_nest,
+    operator.BIM_OT_select_components,
+    operator.BIM_OT_select_nest,
+    operator.BIM_OT_unassign_object,
+    prop.BIMObjectNestProperties,
+    ui.BIM_PT_nest,
+)
+
+
+def register():
+    bpy.types.Object.BIMObjectNestProperties = bpy.props.PointerProperty(type=prop.BIMObjectNestProperties)
+
+
+def unregister():
+    del bpy.types.Object.BIMObjectNestProperties

src/blenderbim/blenderbim/bim/module/nest/data.py

@@ -0,0 +1,67 @@
+# BlenderBIM Add-on - OpenBIM Blender Add-on
+# Copyright (C) 2023 Dion Moult <dion@thinkmoult.com>
+#
+# This file is part of BlenderBIM Add-on.
+#
+# BlenderBIM Add-on is free software: you can redistribute it and/or modify
+# it under the terms of the GNU General Public License as published by
+# the Free Software Foundation, either version 3 of the License, or
+# (at your option) any later version.
+#
+# BlenderBIM Add-on 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 General Public License for more details.
+#
+# You should have received a copy of the GNU General Public License
+# along with BlenderBIM Add-on.  If not, see <http://www.gnu.org/licenses/>.
+
+import bpy
+import blenderbim.tool as tool
+import ifcopenshell.util.element
+
+
+def refresh():
+    NestData.is_loaded = False
+
+
+class NestData:
+    data = {}
+    is_loaded = False
+
+    @classmethod
+    def load(cls):
+        cls.data = {
+            "has_relating_object": cls.has_relating_object(),
+            "relating_object_label": cls.get_relating_object_label(),
+            "has_related_objects": cls.has_related_objects(),
+            "total_components": cls.total_components(),
+        }
+        cls.is_loaded = True
+
+    @classmethod
+    def get_relating_object(cls):
+        return ifcopenshell.util.element.get_nest(tool.Ifc.get_entity(bpy.context.active_object))
+
+    @classmethod
+    def has_relating_object(cls) -> bool:
+        return cls.get_relating_object() is not None
+
+    @classmethod
+    def get_relating_object_label(cls) -> str:
+        nest = cls.get_relating_object()
+        if nest:
+            return f"{nest.is_a()}/{nest.Name or ''}"
+
+    @classmethod
+    def get_related_objects(cls):
+        return ifcopenshell.util.element.get_components(tool.Ifc.get_entity(bpy.context.active_object))
+
+    @classmethod
+    def total_components(cls):
+        components = cls.get_related_objects()
+        return len(components) if components else 0
+
+    @classmethod
+    def has_related_objects(cls) -> bool:
+        return bool(cls.get_related_objects())

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

@@ -0,0 +1,151 @@
+# BlenderBIM Add-on - OpenBIM Blender Add-on
+# Copyright (C) 2023 Dion Moult <dion@thinkmoult.com>
+#
+# This file is part of BlenderBIM Add-on.
+#
+# BlenderBIM Add-on is free software: you can redistribute it and/or modify
+# it under the terms of the GNU General Public License as published by
+# the Free Software Foundation, either version 3 of the License, or
+# (at your option) any later version.
+#
+# BlenderBIM Add-on 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 General Public License for more details.
+#
+# You should have received a copy of the GNU General Public License
+# along with BlenderBIM Add-on.  If not, see <http://www.gnu.org/licenses/>.
+
+import bpy
+import ifcopenshell
+import ifcopenshell.util.element
+import blenderbim.tool as tool
+import blenderbim.core.nest as core
+import blenderbim.core.spatial
+import blenderbim.bim.handler
+from blenderbim.bim.ifc import IfcStore
+
+
+class Operator:
+    def execute(self, context):
+        IfcStore.execute_ifc_operator(self, context)
+        blenderbim.bim.handler.refresh_ui_data()
+        return {"FINISHED"}
+
+
+class BIM_OT_assign_object(bpy.types.Operator, Operator):
+    """Create nest relationship between two ifc elements"""
+
+    bl_idname = "bim.assign_object"
+    bl_label = "Assign Object"
+    bl_options = {"REGISTER", "UNDO"}
+    relating_object: bpy.props.IntProperty()
+
+    def _execute(self, context):
+        relating_obj = None
+        if self.relating_object:
+            relating_obj = tool.Ifc.get_object(tool.Ifc.get().by_id(self.relating_object))
+        elif context.active_object:
+            relating_obj = context.active_object
+        if not relating_obj:
+            return
+
+        for obj in bpy.context.selected_objects:
+            if obj == relating_obj:
+                continue
+            element = tool.Ifc.get_entity(obj)
+            if not element:
+                continue
+            result = core.assign_object(
+                tool.Ifc,
+                tool.Nest,
+                tool.Collector,
+                relating_obj=relating_obj,
+                related_obj=obj,
+            )
+            if not result:
+                self.report({"ERROR"}, f" Cannot nest {obj.name} to {relating_obj.name}")
+
+
+class BIM_OT_unassign_object(bpy.types.Operator, Operator):
+    """Remove nest relationship between two ifc elements"""
+
+    bl_idname = "bim.unassign_object"
+    bl_label = "Unassign Object"
+    bl_options = {"REGISTER", "UNDO"}
+
+    def _execute(self, context):
+        for obj in bpy.context.selected_objects:
+            element = tool.Ifc.get_entity(obj)
+            if not element:
+                continue
+            nest = ifcopenshell.util.element.get_nest(element)
+            if not nest:
+                continue
+            core.unassign_object(
+                tool.Ifc,
+                tool.Nest,
+                tool.Collector,
+                relating_obj=tool.Ifc.get_object(nest),
+                related_obj=tool.Ifc.get_object(element),
+            )
+
+
+class BIM_OT_enable_editing_nest(bpy.types.Operator, Operator):
+    """Enable editing nest relationship"""
+
+    bl_idname = "bim.enable_editing_nest"
+    bl_label = "Enable Editing Nest"
+    bl_options = {"REGISTER", "UNDO"}
+
+    def _execute(self, context):
+        core.enable_editing_nest(tool.Nest, obj=context.active_object)
+
+
+class BIM_OT_disable_editing_nest(bpy.types.Operator, Operator):
+    """Disable editing nest relationship"""
+
+    bl_idname = "bim.disable_editing_nest"
+    bl_label = "Disable Editing Nest"
+    bl_options = {"REGISTER", "UNDO"}
+
+    def _execute(self, context):
+        core.disable_editing_nest(tool.Nest, obj=context.active_object)
+
+
+class BIM_OT_select_components(bpy.types.Operator):
+    """Select Components"""
+
+    bl_idname = "bim.select_components"
+    bl_label = "Select Components"
+    bl_options = {"REGISTER", "UNDO"}
+    obj: bpy.props.StringProperty()
+
+    def execute(self, context):
+        self.file = IfcStore.get_file()
+        obj = bpy.data.objects.get(self.obj) or context.active_object
+        components = ifcopenshell.util.element.get_components(tool.Ifc.get_entity(obj))
+        component_objs = set(tool.Ifc.get_object(c) for c in components)
+        selectable_component_objs = set(context.selectable_objects).intersection(component_objs)
+        for selectable_component_obj in selectable_component_objs:
+            selectable_component_obj.select_set(True)
+        return {"FINISHED"}
+
+
+class BIM_OT_select_nest(bpy.types.Operator):
+    """Select Nest"""
+
+    bl_idname = "bim.select_nest"
+    bl_label = "Select Nest"
+    bl_options = {"REGISTER", "UNDO"}
+    obj: bpy.props.StringProperty()
+
+    def execute(self, context):
+        self.file = IfcStore.get_file()
+        obj = bpy.data.objects.get(self.obj) or context.active_object
+        nest = ifcopenshell.util.element.get_nest(tool.Ifc.get_entity(obj))
+        nest_obj = tool.Ifc.get_object(nest)
+        if nest_obj in context.selectable_objects:
+            nest_obj.select_set(True)
+            bpy.context.view_layer.objects.active = nest_obj
+        return {"FINISHED"}

src/blenderbim/blenderbim/bim/module/nest/prop.py

@@ -0,0 +1,48 @@
+# BlenderBIM Add-on - OpenBIM Blender Add-on
+# Copyright (C) 2023 Dion Moult <dion@thinkmoult.com>
+#
+# This file is part of BlenderBIM Add-on.
+#
+# BlenderBIM Add-on is free software: you can redistribute it and/or modify
+# it under the terms of the GNU General Public License as published by
+# the Free Software Foundation, either version 3 of the License, or
+# (at your option) any later version.
+#
+# BlenderBIM Add-on 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 General Public License for more details.
+#
+# You should have received a copy of the GNU General Public License
+# along with BlenderBIM Add-on.  If not, see <http://www.gnu.org/licenses/>.
+
+import bpy
+from blenderbim.bim.prop import StrProperty, Attribute
+from blenderbim.bim.module.spatial.data import SpatialData
+from bpy.types import PropertyGroup
+from bpy.props import (
+    PointerProperty,
+    StringProperty,
+    EnumProperty,
+    BoolProperty,
+    IntProperty,
+    FloatProperty,
+    FloatVectorProperty,
+    CollectionProperty,
+)
+
+
+def update_relating_object(self, context):
+    def message(self, context):
+        self.layout.label(text="Please select a valid Ifc Element")
+
+    if self.relating_object is None:
+        return
+    if not self.relating_object.BIMObjectProperties.ifc_definition_id:
+        context.window_manager.popup_menu(message, title="Invalid Element Selected", icon="INFO")
+        self.relating_object = None
+
+
+class BIMObjectNestProperties(PropertyGroup):
+    is_editing: BoolProperty(name="Is Editing")
+    relating_object: PointerProperty(name="Nest Host", type=bpy.types.Object, update=update_relating_object)

src/blenderbim/blenderbim/bim/module/nest/ui.py

@@ -0,0 +1,83 @@
+# BlenderBIM Add-on - OpenBIM Blender Add-on
+# Copyright (C) 2023 Dion Moult <dion@thinkmoult.com>
+#
+# This file is part of BlenderBIM Add-on.
+#
+# BlenderBIM Add-on is free software: you can redistribute it and/or modify
+# it under the terms of the GNU General Public License as published by
+# the Free Software Foundation, either version 3 of the License, or
+# (at your option) any later version.
+#
+# BlenderBIM Add-on 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 General Public License for more details.
+#
+# You should have received a copy of the GNU General Public License
+# along with BlenderBIM Add-on.  If not, see <http://www.gnu.org/licenses/>.
+
+from bpy.types import Panel
+from blenderbim.bim.module.nest.data import NestData
+from blenderbim.bim.ifc import IfcStore
+
+
+class BIM_PT_nest(Panel):
+    bl_label = "Nest"
+    bl_idname = "BIM_PT_nest"
+    bl_options = {"DEFAULT_CLOSED"}
+    bl_space_type = "PROPERTIES"
+    bl_region_type = "WINDOW"
+    bl_context = "object"
+    bl_parent_id = "BIM_PT_tab_object_metadata"
+
+    @classmethod
+    def poll(cls, context):
+        if not context.active_object:
+            return False
+        props = context.active_object.BIMObjectProperties
+        if not props.ifc_definition_id:
+            return False
+        if not IfcStore.get_element(props.ifc_definition_id):
+            return False
+        if not IfcStore.get_file().by_id(props.ifc_definition_id).is_a("IfcObjectDefinition"):
+            return False
+        return True
+
+    def draw(self, context):
+        layout = self.layout
+        if not NestData.is_loaded:
+            NestData.load()
+
+        props = context.active_object.BIMObjectNestProperties
+
+        if props.is_editing:
+            row = layout.row(align=True)
+            row.prop(props, "relating_object", text="")
+            if props.relating_object:
+                op = row.operator("bim.assign_object", icon="CHECKMARK", text="")
+                op.relating_object = props.relating_object.BIMObjectProperties.ifc_definition_id
+            row.operator("bim.disable_editing_nest", icon="CANCEL", text="")
+        else:
+            row = layout.row(align=True)
+            if NestData.data["has_relating_object"]:
+                row.label(text=NestData.data["relating_object_label"], icon="TRIA_UP")
+                op = row.operator("bim.select_nest", icon="RESTRICT_SELECT_OFF", text="")
+                op.obj = context.active_object.name
+                row.operator("bim.enable_editing_nest", icon="GREASEPENCIL", text="")
+                op = row.operator("bim.unassign_object", icon="X", text="")
+            else:
+                row.label(text="No Host", icon="TRIA_UP")
+                row.operator("bim.enable_editing_nest", icon="GREASEPENCIL", text="")
+
+        row = layout.row(align=True)
+        total_components = NestData.data["total_components"]
+        if total_components == 0:
+            row.label(text="No Components", icon="TRIA_DOWN")
+        elif total_components == 1:
+            row.label(text="1 Component", icon="TRIA_DOWN")
+        else:
+            row.label(text=f"{total_components} Components", icon="TRIA_DOWN")
+
+        if NestData.data["has_related_objects"]:
+            op = row.operator("bim.select_components", icon="RESTRICT_SELECT_OFF", text="")
+            op.obj = context.active_object.name

src/blenderbim/blenderbim/core/nest.py

@@ -0,0 +1,58 @@
+# BlenderBIM Add-on - OpenBIM Blender Add-on
+# Copyright (C) 2023 Dion Moult <dion@thinkmoult.com>
+#
+# This file is part of BlenderBIM Add-on.
+#
+# BlenderBIM Add-on is free software: you can redistribute it and/or modify
+# it under the terms of the GNU General Public License as published by
+# the Free Software Foundation, either version 3 of the License, or
+# (at your option) any later version.
+#
+# BlenderBIM Add-on 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 General Public License for more details.
+#
+# You should have received a copy of the GNU General Public License
+# along with BlenderBIM Add-on.  If not, see <http://www.gnu.org/licenses/>.
+
+
+def enable_editing_nest(nest, obj=None):
+    nest.enable_editing(obj)
+
+
+def disable_editing_nest(nest, obj=None):
+    nest.disable_editing(obj)
+
+
+def assign_object(ifc, nest, collector, relating_obj=None, related_obj=None):
+    if not nest.can_nest(relating_obj, related_obj):
+        return
+    rel = ifc.run(
+        "nest.assign_object", related_object=ifc.get_entity(related_obj), relating_object=ifc.get_entity(relating_obj)
+    )
+    collector.assign(relating_obj)
+    collector.assign(related_obj)
+    nest.disable_editing(related_obj)
+    return rel
+
+
+def unassign_object(ifc, nest, collector, relating_obj=None, related_obj=None):
+    related_element = ifc.get_entity(related_obj)
+    container = nest.get_container(related_element)
+    if not relating_obj:
+        relating_element = nest.get_relating_object(related_element)
+        if related_element:
+            relating_obj = ifc.get_object(relating_element)
+    if relating_obj:
+        ifc.run("nest.unassign_object", related_object=related_element)
+        if container:
+            ifc.run("spatial.assign_container", product=related_element, relating_structure=container)
+        collector.assign(relating_obj)
+        collector.assign(related_obj)
+
+
+def add_part_to_object(ifc, nest, collector, blender, obj, part_class, part_name=None):
+    part_obj = blender.create_ifc_object(ifc_class=part_class, name=part_name)
+    assign_object(ifc, nest, collector, relating_obj=obj, related_obj=part_obj)
+    blender.set_active_object(obj)

src/blenderbim/blenderbim/core/tool.py

@@ -507,6 +507,14 @@ class Model:
     def replace_object_ifc_representation(cls, ifc_file, ifc_context, obj, new_representation): pass
 
 
+@interface
+class Nest:
+    def can_nest(cls, relating_object, related_object): pass
+    def disable_editing(cls, obj): pass
+    def enable_editing(cls, obj): pass
+    def get_container(cls, element): pass
+
+
 @interface
 class Patch:
     def run_migrate_patch(cls, infile, outfile, schema): pass

src/blenderbim/blenderbim/tool/__init__.py

@@ -37,6 +37,7 @@ from blenderbim.tool.loader import Loader
 from blenderbim.tool.material import Material
 from blenderbim.tool.misc import Misc
 from blenderbim.tool.model import Model
+from blenderbim.tool.nest import Nest
 from blenderbim.tool.owner import Owner
 from blenderbim.tool.patch import Patch
 from blenderbim.tool.project import Project

src/blenderbim/blenderbim/tool/collector.py

@@ -107,11 +107,12 @@ class Collector(blenderbim.core.tool.Collector):
                     collection.children.unlink(object_collection)
             collection_collection.children.link(object_collection)
 
+        # If an aggregate or nested host loses all its children, it no longer needs its own collection
+        if obj.BIMObjectProperties.collection and obj.BIMObjectProperties.collection != object_collection:
+            bpy.data.collections.remove(obj.BIMObjectProperties.collection)
+
     @classmethod
     def _get_own_collection(cls, element, obj):
-        if obj.BIMObjectProperties.collection:
-            return obj.BIMObjectProperties.collection
-
         if element.is_a("IfcProject"):
             return cls._create_own_collection(obj)
 
@@ -155,6 +156,9 @@ class Collector(blenderbim.core.tool.Collector):
         if getattr(element, "IsDecomposedBy", None):
             return cls._create_own_collection(obj)
 
+        if getattr(element, "IsNestedBy", None):
+            return cls._create_own_collection(obj)
+
     @classmethod
     def _get_collection(cls, element, obj):
         if element.is_a("IfcTypeObject"):
@@ -235,6 +239,8 @@ class Collector(blenderbim.core.tool.Collector):
 
     @classmethod
     def _create_own_collection(cls, obj):
+        if obj.BIMObjectProperties.collection:
+            return obj.BIMObjectProperties.collection
         collection = bpy.data.collections.new(obj.name)
         obj.BIMObjectProperties.collection = collection
         collection.BIMCollectionProperties.obj = obj

src/blenderbim/blenderbim/tool/nest.py

@@ -0,0 +1,49 @@
+# BlenderBIM Add-on - OpenBIM Blender Add-on
+# Copyright (C) 2023 Dion Moult <dion@thinkmoult.com>
+#
+# This file is part of BlenderBIM Add-on.
+#
+# BlenderBIM Add-on is free software: you can redistribute it and/or modify
+# it under the terms of the GNU General Public License as published by
+# the Free Software Foundation, either version 3 of the License, or
+# (at your option) any later version.
+#
+# BlenderBIM Add-on 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 General Public License for more details.
+#
+# You should have received a copy of the GNU General Public License
+# along with BlenderBIM Add-on.  If not, see <http://www.gnu.org/licenses/>.
+
+import blenderbim.core.tool
+import blenderbim.tool as tool
+import ifcopenshell.util.element
+
+
+class Nest(blenderbim.core.tool.Nest):
+    @classmethod
+    def can_nest(cls, relating_obj, related_obj):
+        relating_object = tool.Ifc.get_entity(relating_obj)
+        related_object = tool.Ifc.get_entity(related_obj)
+        if not relating_object or not related_object:
+            return False
+        if relating_object.is_a("IfcElement") and related_object.is_a("IfcElement"):
+            return True
+        return False
+
+    @classmethod
+    def disable_editing(cls, obj):
+        obj.BIMObjectNestProperties.is_editing = False
+
+    @classmethod
+    def enable_editing(cls, obj):
+        obj.BIMObjectNestProperties.is_editing = True
+
+    @classmethod
+    def get_container(cls, element):
+        return ifcopenshell.util.element.get_container(element)
+
+    @classmethod
+    def get_relating_object(cls, related_element):
+        return ifcopenshell.util.element.get_nest(related_element)

src/blenderbim/test/core/bootstrap.py

@@ -126,6 +126,13 @@ def misc():
     prophet.verify()
 
 
+@pytest.fixture
+def nest():
+    prophet = Prophecy(blenderbim.core.tool.Nest)
+    yield prophet
+    prophet.verify()
+
+
 @pytest.fixture
 def owner():
     prophet = Prophecy(blenderbim.core.tool.Owner)

src/blenderbim/test/core/test_nest.py

@@ -0,0 +1,59 @@
+# BlenderBIM Add-on - OpenBIM Blender Add-on
+# Copyright (C) 2021 Dion Moult <dion@thinkmoult.com>
+#
+# This file is part of BlenderBIM Add-on.
+#
+# BlenderBIM Add-on is free software: you can redistribute it and/or modify
+# it under the terms of the GNU General Public License as published by
+# the Free Software Foundation, either version 3 of the License, or
+# (at your option) any later version.
+#
+# BlenderBIM Add-on 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 General Public License for more details.
+#
+# You should have received a copy of the GNU General Public License
+# along with BlenderBIM Add-on.  If not, see <http://www.gnu.org/licenses/>.
+
+import blenderbim.core.nest as subject
+from test.core.bootstrap import ifc, nest, collector
+
+
+class TestEnableEditingNeset:
+    def test_run(self, nest):
+        nest.enable_editing("obj").should_be_called()
+        subject.enable_editing_nest(nest, obj="obj")
+
+
+class TestDisableEditingNest:
+    def test_run(self, nest):
+        nest.disable_editing("obj").should_be_called()
+        subject.disable_editing_nest(nest, obj="obj")
+
+
+class TestAssignObject:
+    def test_run(self, ifc, nest, collector):
+        nest.can_nest("relating_obj", "related_obj").should_be_called().will_return(True)
+        ifc.get_entity("relating_obj").should_be_called().will_return("relating_object")
+        ifc.get_entity("related_obj").should_be_called().will_return("related_object")
+        ifc.run(
+            "nest.assign_object", related_object="related_object", relating_object="relating_object"
+        ).should_be_called().will_return("rel")
+        nest.disable_editing("related_obj").should_be_called()
+        collector.assign("relating_obj").should_be_called()
+        collector.assign("related_obj").should_be_called()
+        assert (
+            subject.assign_object(ifc, nest, collector, relating_obj="relating_obj", related_obj="related_obj") == "rel"
+        )
+
+
+class TestUnassignObject:
+    def test_run(self, ifc, nest, collector):
+        ifc.get_entity("related_obj").should_be_called().will_return("element")
+        nest.get_container("element").should_be_called().will_return("container")
+        ifc.run("spatial.assign_container", product="element", relating_structure="container").should_be_called()
+        ifc.run("nest.unassign_object", related_object="element").should_be_called().will_return("rel")
+        collector.assign("relating_obj").should_be_called()
+        collector.assign("related_obj").should_be_called()
+        subject.unassign_object(ifc, nest, collector, relating_obj="relating_obj", related_obj="related_obj")

src/blenderbim/test/tool/test_aggregate.py

@@ -29,10 +29,6 @@ class TestImplementsTool(NewFile):
         assert isinstance(subject(), blenderbim.core.tool.Aggregate)
 
 
-
-
-
-
 class TestCanAggregate(NewFile):
     def test_elements_can_aggregate(self):
         ifc = ifcopenshell.file()
@@ -107,6 +103,7 @@ class TestCanAggregate(NewFile):
         tool.Ifc.link(subelement, subelement_obj)
         assert subject.can_aggregate(element_obj, subelement_obj) is False
 
+
 class TestDisableEditing(NewFile):
     def test_run(self):
         obj = bpy.data.objects.new("Object", None)

src/blenderbim/test/tool/test_nest.py

@@ -0,0 +1,74 @@
+# BlenderBIM Add-on - OpenBIM Blender Add-on
+# Copyright (C) 2021 Dion Moult <dion@thinkmoult.com>
+#
+# This file is part of BlenderBIM Add-on.
+#
+# BlenderBIM Add-on is free software: you can redistribute it and/or modify
+# it under the terms of the GNU General Public License as published by
+# the Free Software Foundation, either version 3 of the License, or
+# (at your option) any later version.
+#
+# BlenderBIM Add-on 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 General Public License for more details.
+#
+# You should have received a copy of the GNU General Public License
+# along with BlenderBIM Add-on.  If not, see <http://www.gnu.org/licenses/>.
+
+import bpy
+import ifcopenshell
+import blenderbim.core.tool
+import blenderbim.tool as tool
+from test.bim.bootstrap import NewFile
+from blenderbim.tool.nest import Nest as subject
+
+
+class TestImplementsTool(NewFile):
+    def test_run(self):
+        assert isinstance(subject(), blenderbim.core.tool.Nest)
+
+
+class TestCanNest(NewFile):
+    def test_elements_can_nest(self):
+        ifc = ifcopenshell.file()
+        tool.Ifc.set(ifc)
+        element = ifc.createIfcElementAssembly()
+        element_obj = bpy.data.objects.new("Object", None)
+        tool.Ifc.link(element, element_obj)
+        subelement = ifc.createIfcBeam()
+        subelement_obj = bpy.data.objects.new("Object", None)
+        tool.Ifc.link(subelement, subelement_obj)
+        assert subject.can_nest(element_obj, subelement_obj) is True
+
+    def test_unlinked_elements_cannot_nest(self):
+        ifc = ifcopenshell.file()
+        tool.Ifc.set(ifc)
+        element_obj = bpy.data.objects.new("Object", None)
+        subelement_obj = bpy.data.objects.new("Object", None)
+        assert subject.can_nest(element_obj, subelement_obj) is False
+
+
+class TestDisableEditing(NewFile):
+    def test_run(self):
+        obj = bpy.data.objects.new("Object", None)
+        subject.enable_editing(obj)
+        subject.disable_editing(obj)
+        assert obj.BIMObjectNestProperties.is_editing is False
+
+
+class TestEnableEditing(NewFile):
+    def test_run(self):
+        obj = bpy.data.objects.new("Object", None)
+        subject.enable_editing(obj)
+        assert obj.BIMObjectNestProperties.is_editing is True
+
+
+class TestGetContainer(NewFile):
+    def test_run(self):
+        ifc = ifcopenshell.file()
+        tool.Ifc.set(ifc)
+        element = ifc.createIfcWall()
+        container = ifc.createIfcBuildingStorey()
+        ifcopenshell.api.run("spatial.assign_container", ifc, product=element, relating_structure=container)
+        assert subject.get_container(element) == container

src/ifcopenshell-python/ifcopenshell/util/element.py

@@ -805,7 +805,8 @@ def get_aggregate(element):
     aggregate = ifcopenshell.util.element.get_aggregate(element)
     """
     if hasattr(element, "Decomposes") and element.Decomposes:
-        return element.Decomposes[0].RelatingObject
+        if element.Decomposes[0].is_a("IfcRelAggregates"):  # IFC2X3
+            return element.Decomposes[0].RelatingObject
 
 
 def get_nest(element):
@@ -821,13 +822,17 @@ def get_nest(element):
     element = file.by_type("IfcBeam")[0]
     aggregate = ifcopenshell.util.element.get_nest(element)
     """
-    if hasattr(element, "Nests") and element.Nests:
-        return element.Nests[0].RelatingObject
+    if hasattr(element, "Nests"):
+        if element.Nests:
+            return element.Nests[0].RelatingObject
+    elif hasattr(element, "Decomposes") and element.Decomposes:  # IFC2X3
+        if element.Decomposes[0].is_a("IfcRelNests"):
+            return element.Decomposes[0].RelatingObject
 
 
 def get_parts(element):
     """
-    Retrieves the parts of an element.
+    Retrieves the parts of an element that have an aggregation relationship.
 
     :param element: The IFC element
     :return: The parts of the element
@@ -840,7 +845,30 @@ def get_parts(element):
 
     """
     if hasattr(element, "IsDecomposedBy") and element.IsDecomposedBy:
-        return element.IsDecomposedBy[0].RelatedObjects
+        if element.IsDecomposedBy[0].is_a("IfcRelAggregates"):
+            return element.IsDecomposedBy[0].RelatedObjects
+
+
+def get_components(element):
+    """
+    Retrieves the components of an element that have an nest relationship.
+
+    :param element: The IFC element
+    :return: The components of the element
+
+    Example:
+
+    .. code:: python
+    element = file.by_type("IfcElementAssembly")[0]
+    components = ifcopenshell.util.element.get_components(element)
+
+    """
+    if hasattr(element, "IsNestedBy"):
+        if element.IsNestedBy:
+            return element.IsNestedBy[0].RelatedObjects
+    elif hasattr(element, "IsDecomposedBy") and element.IsDecomposedBy:
+        if element.IsDecomposedBy[0].is_a("IfcRelNests"):
+            return element.IsDecomposedBy[0].RelatedObjects
 
 
 def replace_attribute(element, old, new):