Save loaded paths to linked IFC models in IFC #5899

Short demo - https://imgur.com/a/3LIt9Sr

src/bonsai/bonsai/bim/export_ifc.py

@@ -49,6 +49,7 @@ class IfcExporter:
         IfcStore.update_cache()
         self.sync_all_objects()
         self.sync_edited_objects()
+        tool.Project.save_linked_models_to_ifc()
         extension = self.ifc_export_settings.output_file.split(".")[-1].lower()
         if extension == "ifczip":
             with tempfile.TemporaryDirectory() as unzipped_path:

src/bonsai/bonsai/bim/import_ifc.py

@@ -258,6 +258,8 @@ class IfcImporter:
         self.profile_code("Place objects in collections")
         self.setup_arrays()
         self.profile_code("Setup arrays")
+        tool.Project.load_linked_models_from_ifc()
+        self.profile_code("Load linked models")
         self.lock_scales()
         self.profile_code("Lock objects scales")
         self.add_project_to_scene()

src/bonsai/bonsai/tool/document.py

@@ -21,7 +21,7 @@ import ifcopenshell.util.system
 import bonsai.bim.helper
 import bonsai.core.tool
 import bonsai.tool as tool
-from typing import Any, Union
+from typing import Any, Union, Sequence
 
 
 class Document(bonsai.core.tool.Document):
@@ -102,7 +102,7 @@ class Document(bonsai.core.tool.Document):
     def import_references(cls, document: ifcopenshell.entity_instance) -> None:
         props = bpy.context.scene.BIMDocumentProperties
         is_ifc2x3 = tool.Ifc.get_schema() == "IFC2X3"
-        references = (document.DocumentReferences or []) if is_ifc2x3 else document.HasDocumentReferences
+        references = cls.get_document_references(document)
         for element in references:
             new = props.documents.add()
             new.ifc_definition_id = element.id()
@@ -157,3 +157,12 @@ class Document(bonsai.core.tool.Document):
     def set_external_reference_id(cls, reference: ifcopenshell.entity_instance, value: Union[str, None]) -> None:
         """Set IfcExternalReference.ItemReference/Identification, compatible with IFC2X3."""
         reference[1] = value
+
+    @classmethod
+    def get_document_references(
+        cls, document: ifcopenshell.entity_instance
+    ) -> tuple[ifcopenshell.entity_instance, ...]:
+        """Get IfcDocumentReference.ReferencedDocuments, compatible with IFC2X3."""
+        if document.file.schema == "IFC2X3":
+            return document.DocumentReferences or ()
+        return document.HasDocumentReferences

src/bonsai/bonsai/tool/project.py

@@ -19,6 +19,7 @@
 import os
 import bpy
 import ifcopenshell
+import ifcopenshell.api.document
 import ifcopenshell.util.representation
 import ifcopenshell.util.unit
 import bonsai.core.aggregate
@@ -32,7 +33,7 @@ import bonsai.tool as tool
 from bonsai.bim.ifc import IfcStore
 from ifcopenshell.api.project.append_asset import APPENDABLE_ASSET_TYPES
 from pathlib import Path
-from typing import Optional
+from typing import Optional, Union
 
 
 class Project(bonsai.core.tool.Project):
@@ -214,3 +215,74 @@ class Project(bonsai.core.tool.Project):
     @classmethod
     def run_root_reload_grid_decorator(cls) -> None:
         tool.Root.reload_grid_decorator()
+
+    @classmethod
+    def get_linked_models_document(cls) -> Union[ifcopenshell.entity_instance, None]:
+        for document in tool.Ifc.get().by_type("IfcDocumentInformation"):
+            if document.Name == "BBIM_Linked_Models":
+                return document
+
+    @classmethod
+    def load_linked_models_from_ifc(cls) -> None:
+        links = bpy.context.scene.BIMProjectProperties.links
+        links.clear()
+        links_document = cls.get_linked_models_document()
+        if not links_document:
+            return
+
+        references = tool.Document.get_document_references(links_document)
+        if not references:
+            return
+
+        for reference in references:
+            link = links.add()
+            link.name = reference.Location
+
+    @classmethod
+    def save_linked_models_to_ifc(cls) -> None:
+        ifc_file = tool.Ifc.get()
+        links = bpy.context.scene.BIMProjectProperties.links
+        filepaths: set[Path] = set()
+        for link in links:
+            filepaths.add(Path(link.name))
+
+        links_document = next(
+            (
+                document
+                for document in ifc_file.by_type("IfcDocumentInformation")
+                if document.Name == "BBIM_Linked_Models"
+            ),
+            None,
+        )
+
+        if not filepaths and links_document is None:
+            return
+
+        paths_to_add = filepaths.copy()
+        references_to_remove: list[ifcopenshell.entity_instance] = []
+        if links_document:
+            references = tool.Document.get_document_references(links_document)
+            for reference in references:
+                # I guess got corrupted by the user.
+                if not (location := reference.Location):
+                    references_to_remove.remove(reference)
+                    continue
+                path = Path(location)
+                if path in paths_to_add:
+                    paths_to_add.remove(path)
+                else:
+                    references_to_remove.append(reference)
+
+        if paths_to_add:
+            if links_document is None:
+                links_document = ifcopenshell.api.document.add_information(ifc_file)
+                links_document.Name = "BBIM_Linked_Models"
+                links_document.Description = "Bonsai internal document containing references to currently linked models"
+
+            for path in paths_to_add:
+                reference = ifcopenshell.api.document.add_reference(ifc_file, links_document)
+                reference.Location = path.as_posix()
+
+        if references_to_remove:
+            for reference in references_to_remove:
+                ifcopenshell.api.document.remove_reference(ifc_file, reference)

src/bonsai/test/tool/test_project.py

@@ -18,6 +18,8 @@
 
 import bpy
 import ifcopenshell
+import ifcopenshell.api.document
+import ifcopenshell.api.root
 import bonsai.core.tool
 import bonsai.tool as tool
 import tempfile
@@ -238,3 +240,108 @@ class TestLoadProject(NewFile):
         assert not tool.Ifc.get()
         assert bpy.data.objects["IfcWall/Wall"]
         assert tool.Blender.is_valid_data_block(monkey)
+
+
+class TestLoadLinkedModels(NewFile):
+    def test_load_linked_models_no_document(self):
+        links = bpy.context.scene.BIMProjectProperties.links
+        ifc = ifcopenshell.file()
+        tool.Ifc.set(ifc)
+        subject.load_linked_models_from_ifc()
+        assert len(links) == 0
+
+    def test_load_linked_models_document_no_references(self):
+        ifc = ifcopenshell.file()
+        links = bpy.context.scene.BIMProjectProperties.links
+        ifcopenshell.api.root.create_entity(ifc, "IfcProject")
+        document = ifcopenshell.api.document.add_information(ifc)
+        document.Name = "BBIM_Linked_Models"
+        tool.Ifc.set(ifc)
+        subject.load_linked_models_from_ifc()
+        assert len(links) == 0
+
+    def test_load_linked_models_document_with_references(self):
+        ifc = ifcopenshell.file()
+        links = bpy.context.scene.BIMProjectProperties.links
+        ifcopenshell.api.root.create_entity(ifc, "IfcProject")
+        document = ifcopenshell.api.document.add_information(ifc)
+        document.Name = "BBIM_Linked_Models"
+        reference = ifcopenshell.api.document.add_reference(ifc, document)
+        linked_model_path = "test.ifc"
+        reference.Location = linked_model_path
+        tool.Ifc.set(ifc)
+        subject.load_linked_models_from_ifc()
+        assert len(links) == 1
+        assert links[0].name == linked_model_path
+
+
+class TestSaveLinkedModelsToIfc(NewFile):
+    def test_save_linked_models_to_ifc_no_links(self):
+        ifc = ifcopenshell.file()
+        tool.Ifc.set(ifc)
+        subject.save_linked_models_to_ifc()
+        assert len(ifc.by_type("IfcDocumentInformation")) == 0
+        assert len(ifc.by_type("IfcDocumentReference")) == 0
+
+    def test_save_linked_models_to_ifc_paths_to_add(self):
+        ifc = ifcopenshell.file()
+        ifcopenshell.api.root.create_entity(ifc, "IfcProject")
+        links = bpy.context.scene.BIMProjectProperties.links
+        link = links.add()
+        linked_model_path = "test.ifc"
+        link.name = linked_model_path
+        tool.Ifc.set(ifc)
+        subject.save_linked_models_to_ifc()
+        assert len(documents := ifc.by_type("IfcDocumentInformation")) == 1
+        assert documents[0].Name == "BBIM_Linked_Models"
+        assert len(references := ifc.by_type("IfcDocumentReference")) == 1
+        assert references[0].Location == linked_model_path
+
+    def test_save_linked_models_to_ifc_already_created_references(self):
+        ifc = ifcopenshell.file()
+        links = bpy.context.scene.BIMProjectProperties.links
+        ifcopenshell.api.root.create_entity(ifc, "IfcProject")
+
+        document = ifcopenshell.api.document.add_information(ifc)
+        document.Name = "BBIM_Linked_Models"
+        document_id = document.id()
+        reference = ifcopenshell.api.document.add_reference(ifc, document)
+        linked_model_path = "test.ifc"
+        reference.Location = linked_model_path
+        reference_id = reference.id()
+
+        link = links.add()
+        linked_model_path = "test.ifc"
+        link.name = linked_model_path
+        tool.Ifc.set(ifc)
+        subject.save_linked_models_to_ifc()
+
+        # Information and references to stay intact.
+        assert len(documents := ifc.by_type("IfcDocumentInformation")) == 1
+        assert documents[0].id() == document_id
+        assert documents[0].Name == "BBIM_Linked_Models"
+        assert len(references := ifc.by_type("IfcDocumentReference")) == 1
+        assert references[0].id() == reference_id
+        assert references[0].Location == linked_model_path
+
+    def test_save_linked_models_to_ifc_references_to_remove(self):
+        ifc = ifcopenshell.file()
+        links = bpy.context.scene.BIMProjectProperties.links
+        ifcopenshell.api.root.create_entity(ifc, "IfcProject")
+
+        document = ifcopenshell.api.document.add_information(ifc)
+        document.Name = "BBIM_Linked_Models"
+        document_id = document.id()
+        reference = ifcopenshell.api.document.add_reference(ifc, document)
+        linked_model_path = "test.ifc"
+        reference.Location = linked_model_path
+
+        tool.Ifc.set(ifc)
+        subject.save_linked_models_to_ifc()
+        links.clear()
+
+        # Remove reference for removed link.
+        assert len(documents := ifc.by_type("IfcDocumentInformation")) == 1
+        assert documents[0].id() == document_id
+        assert documents[0].Name == "BBIM_Linked_Models"
+        assert len(ifc.by_type("IfcDocumentReference")) == 0