Library UI - tree view

Example of tree view with libraries hierarchy - https://imgur.com/a/zPuaoPv
Example of library assignment in non-tree view - https://imgur.com/a/9kZFblj

src/bonsai/bonsai/bim/module/project/__init__.py

@@ -66,6 +66,7 @@ classes = (
     operator.UnlinkIfc,
     operator.UnloadLink,
     workspace.ExploreHotkey,
+    prop.LibraryBreadcrumb,
     prop.LibraryElement,
     prop.FilterCategory,
     prop.Link,

src/bonsai/bonsai/bim/module/project/data.py

@@ -134,10 +134,11 @@ class ProjectLibraryData:
 
     @classmethod
     def project_libraries_enum(cls) -> list[tuple[str, str, str, str, int]]:
-        results = [
-            ("*", "All Libraries", "Show all elements", "", 0),
-            ("-", "No Library", "Show elements without library assigned", "", 1),
-        ]
+        results = []
+        project_libraries = cls.data["project_libraries"].values()
+        if not project_libraries:
+            results.append(("-", "No Library", "", "", 0))
+
         props = tool.Project.get_project_props()
         libs = []
         for i, data in enumerate(cls.data["project_libraries"].values(), len(results)):

src/bonsai/bonsai/bim/module/project/operator.py

@@ -60,9 +60,10 @@ from bpy.app.handlers import persistent
 from ifcopenshell.geom import ShapeElementType
 from bonsai.bim.module.project.data import LinksData, ProjectLibraryData
 from bonsai.bim.module.project.decorator import ProjectDecorator, ClippingPlaneDecorator, MeasureDecorator
+from bonsai.bim.module.project.prop import BreadcrumbType
 from bonsai.bim.module.model.decorator import PolylineDecorator
 from bonsai.bim.module.model.polyline import PolylineOperator
-from typing import Union, TYPE_CHECKING
+from typing import Union, TYPE_CHECKING, Literal, get_args
 
 
 class NewProject(bpy.types.Operator):
@@ -184,6 +185,7 @@ class SelectLibraryFile(bpy.types.Operator, IFCFileSelector):
             context.area.tag_redraw()
         if self.append_all:
             bpy.ops.bim.append_entire_library()
+        ProjectLibraryData.load()
         return {"FINISHED"}
 
     def invoke(self, context, event):
@@ -218,16 +220,27 @@ class RefreshLibrary(bpy.types.Operator):
         self.props.library_elements.clear()
         self.props.library_breadcrumb.clear()
 
-        self.props.active_library_element = ""
-
         library_file = IfcStore.library_file
         assert library_file
 
-        condition = tool.Project.get_filter_for_active_library()
-        for importable_type in sorted(tool.Project.get_appendable_asset_types()):
-            if (elements := library_file.by_type(importable_type)) and (elements := list(condition(elements))):
-                elements = self.props.add_library_asset_group(importable_type, len(elements))
+        if not self.props.show_library_tree:
+            for appendable_type in sorted(tool.Project.get_appendable_asset_types()):
+                elements = library_file.by_type(appendable_type)
+                self.props.add_library_asset_class(appendable_type, len(elements))
+            return {"FINISHED"}
 
+        # Library tree.
+        # Add entry for unassigned elements.
+        elements = set()
+        for importable_type in sorted(tool.Project.get_appendable_asset_types()):
+            elements.update(library_file.by_type(importable_type))
+        rels = tool.Project.get_project_library_rels(library_file)
+        elements = {e for e in elements if not tool.Project.is_element_assigned_to_project_library(e, rels)}
+        self.props.add_library_project_library("Unassigned", len(elements), 0)
+
+        ifc_project = library_file.by_type("IfcProject")[0]
+        hierarchy = tool.Project.get_project_hierarchy(library_file)
+        tool.Project.load_project_libraries_to_ui(ifc_project, hierarchy)
         return {"FINISHED"}
 
 
@@ -235,10 +248,14 @@ class ChangeLibraryElement(bpy.types.Operator):
     bl_idname = "bim.change_library_element"
     bl_label = "Change Library Element"
     bl_options = {"REGISTER", "UNDO"}
-    element_name: bpy.props.StringProperty(description="IFC class to select")
+    element_name: bpy.props.StringProperty()
+    breadcrumb_type: bpy.props.EnumProperty(items=[(i, i, "") for i in get_args(BreadcrumbType)])
+    library_id: bpy.props.IntProperty()
 
     if TYPE_CHECKING:
         element_name: str
+        breadcrumb_type: BreadcrumbType
+        library_id: int
 
     def execute(self, context):
         self.props = tool.Project.get_project_props()
@@ -246,33 +263,81 @@ class ChangeLibraryElement(bpy.types.Operator):
         library_file = IfcStore.library_file
         assert library_file
         self.library_file = library_file
-        self.props.active_library_element = self.element_name
 
         crumb = self.props.library_breadcrumb.add()
         crumb.name = self.element_name
+        crumb.breadcrumb_type = self.breadcrumb_type
+        if self.breadcrumb_type == "LIBRARY":
+            crumb.library_id = self.library_id
 
-        filter_elements = tool.Project.get_filter_for_active_library()
-        elements = self.library_file.by_type(self.element_name)
-        elements = list(filter_elements(elements))
-        ifc_classes_elements: dict[str, list[ifcopenshell.entity_instance]] = defaultdict(list)
-        for element in elements:
-            ifc_classes_elements[element.is_a()].append(element)
+        active_project_library = None
+        library_elements = None
+        project_library_rels = None
+        # Reverse to get last library in hierarchy.
+        for entry in reversed(self.props.library_breadcrumb):
+            if entry.breadcrumb_type == "LIBRARY":
+                if entry.library_id == 0:
+                    # For unassigned elements.
+                    active_project_library = "NO_LIBRARY"
+                    project_library_rels = tool.Project.get_project_library_rels(library_file)
+                else:
+                    active_project_library = library_file.by_id(entry.library_id)
+                    library_elements = tool.Project.get_project_library_elements(active_project_library)
+                break
+
+        def filter_elements(elements: list[ifcopenshell.entity_instance]) -> list[ifcopenshell.entity_instance]:
+            if active_project_library is None:
+                return elements
+            elif active_project_library == "NO_LIBRARY":
+                assert project_library_rels is not None
+                return [
+                    element
+                    for element in elements
+                    if not tool.Project.is_element_assigned_to_project_library(element, project_library_rels)
+                ]
+            else:
+                assert library_elements is not None
+                return [e for e in elements if e in library_elements]
 
         self.props.library_elements.clear()
 
-        if len(ifc_classes_elements) == 1 and list(ifc_classes_elements)[0] == self.element_name:
-            for name, ifc_definition_id in sorted(
-                [(self.get_name(e), e.id()) for e in ifc_classes_elements[self.element_name]]
-            ):
-                self.add_library_asset(name, ifc_definition_id)
-        else:
-            for ifc_class in sorted(ifc_classes_elements):
-                if ifc_class == self.element_name:
-                    continue
-                self.props.add_library_asset_group(ifc_class, len(ifc_classes_elements[ifc_class]))
-            elements_ = ifc_classes_elements[self.element_name]
-            for name, ifc_definition_id, ifc_class in sorted([(self.get_name(e), e.id(), e.is_a()) for e in elements_]):
-                self.add_library_asset(name, ifc_definition_id)
+        if self.breadcrumb_type == "LIBRARY":
+            hierarchy = tool.Project.get_project_hierarchy(library_file)
+            assert active_project_library is not None
+            if active_project_library == "NO_LIBRARY" or not hierarchy[active_project_library]:
+                for appendable_type in sorted(tool.Project.get_appendable_asset_types()):
+                    elements = library_file.by_type(appendable_type)
+                    if elements := filter_elements(elements):
+                        self.props.add_library_asset_class(appendable_type, len(elements))
+            else:
+                tool.Project.load_project_libraries_to_ui(active_project_library, hierarchy)
+        else:  # breadcrumb_type CLASS.
+            elements = self.library_file.by_type(self.element_name)
+            elements = list(filter_elements(elements))
+            ifc_classes_elements: dict[str, list[ifcopenshell.entity_instance]] = defaultdict(list)
+            for element in elements:
+                ifc_classes_elements[element.is_a()].append(element)
+
+            if len(ifc_classes_elements) == 1 and list(ifc_classes_elements)[0] == self.element_name:
+                for name, ifc_definition_id in sorted(
+                    [(self.get_name(e), e.id()) for e in ifc_classes_elements[self.element_name]]
+                ):
+                    self.add_library_asset(name, ifc_definition_id)
+            else:
+                for ifc_class in sorted(ifc_classes_elements):
+                    if ifc_class == self.element_name:
+                        continue
+                    self.props.add_library_asset_class(ifc_class, len(ifc_classes_elements[ifc_class]))
+                elements_ = ifc_classes_elements[self.element_name]
+                for name, ifc_definition_id, ifc_class in sorted(
+                    [(self.get_name(e), e.id(), e.is_a()) for e in elements_]
+                ):
+                    self.add_library_asset(name, ifc_definition_id)
+
+        # Could occur if all elements were assigned to a different library.
+        if len(self.props.library_elements) == 0:
+            bpy.ops.bim.rewind_library()
+
         return {"FINISHED"}
 
     def get_name(self, element: ifcopenshell.entity_instance) -> str:
@@ -300,10 +365,7 @@ class ChangeLibraryElement(bpy.types.Operator):
         elif has_context := element.HasContext:
             relating_context: ifcopenshell.entity_instance
             relating_context = has_context[0].RelatingContext
-            if selected_library in ("-", "*"):
-                new.is_declared = relating_context.is_a("IfcProjectLibrary")
-            else:
-                new.is_declared = relating_context == self.library_file.by_id(int(selected_library))
+            new.is_declared = relating_context == self.library_file.by_id(int(selected_library))
 
         # is_appended.
         try:
@@ -329,10 +391,17 @@ class RewindLibrary(bpy.types.Operator):
         if total_breadcrumbs < 2:
             bpy.ops.bim.refresh_library()
             return {"FINISHED"}
-        element_name = self.props.library_breadcrumb[total_breadcrumbs - 2].name
+        current_element = self.props.library_breadcrumb[total_breadcrumbs - 2]
+        element_name = current_element.name
+        breadcrumb_type = current_element.breadcrumb_type
+        library_id = current_element.library_id
         self.props.library_breadcrumb.remove(total_breadcrumbs - 1)
         self.props.library_breadcrumb.remove(total_breadcrumbs - 2)
-        bpy.ops.bim.change_library_element(element_name=element_name)
+        bpy.ops.bim.change_library_element(
+            element_name=element_name,
+            breadcrumb_type=breadcrumb_type,
+            library_id=library_id,
+        )
         return {"FINISHED"}
 
 
@@ -360,10 +429,7 @@ class AssignLibraryDeclaration(bpy.types.Operator):
         library_file = IfcStore.library_file
         assert library_file
 
-        if props.selected_project_library in ("*", "-"):
-            project_library = library_file.by_type("IfcProjectLibrary")[0]
-        else:
-            project_library = library_file.by_id(int(props.selected_project_library))
+        project_library = library_file.by_id(int(props.selected_project_library))
 
         ifcopenshell.api.project.assign_declaration(
             library_file,
@@ -648,6 +714,7 @@ class EditProjectLibrary(bpy.types.Operator):
                     ifcopenshell.api.nest.assign_object(library_file, [project_library], new_parent_library)
 
         props.is_editing_project_library = False
+        bpy.ops.bim.refresh_library()
         return {"FINISHED"}
 
     def rollback(self, data):

src/bonsai/bonsai/bim/module/project/prop.py

@@ -35,7 +35,7 @@ from bpy.props import (
     IntProperty,
     StringProperty,
 )
-from typing import TYPE_CHECKING, Literal, Union
+from typing import TYPE_CHECKING, Literal, Union, get_args
 
 
 def get_export_schema(self: "BIMProjectProperties", context: bpy.types.Context) -> list[tuple[str, str, str]]:
@@ -67,15 +67,15 @@ def update_library_file(self: "BIMProjectProperties", context: bpy.types.Context
         bpy.ops.bim.select_library_file(filepath=filepath.__str__())
         ProjectLibraryData.load()
         props = tool.Project.get_project_props()
-        props.selected_project_library = "*"
+        library_file = IfcStore.library_file
+        assert library_file
+        project_library = next(iter(library_file.by_type("IfcProjectLibrary")), None)
+        props.selected_project_library = str(project_library.id()) if project_library else "-"
 
 
 def update_selected_project_library(self: "BIMProjectProperties", context: bpy.types.Context) -> None:
-    if self.filter_by_library:
-        bpy.ops.bim.refresh_library()
-    else:
-        # Ensure `.is_declared` up to date.
-        tool.Project.update_current_library_page()
+    # Ensure `.is_declared` up to date.
+    tool.Project.update_current_library_page()
 
 
 def get_project_libaries(self: "BIMProjectProperties", context: bpy.types.Context) -> list[tuple[str, str, str]]:
@@ -84,10 +84,7 @@ def get_project_libaries(self: "BIMProjectProperties", context: bpy.types.Contex
     return ProjectLibraryData.data["project_libraries_enum"]
 
 
-def filter_by_library_update(self: "BIMProjectProperties", context: bpy.types.Context) -> None:
-    if self.filter_by_library and self.selected_project_library == "*":
-        # Filter is toggled from OFF to ON, so it was showing all elements previously either way.
-        return
+def show_library_tree_update(self: "BIMProjectProperties", context: bpy.types.Context) -> None:
     bpy.ops.bim.refresh_library()
 
 
@@ -150,8 +147,12 @@ def update_filter_mode(self: "BIMProjectProperties", context: bpy.types.Context)
             new.total_elements = len(ifcopenshell.util.element.get_types(ifc_type))
 
 
+LibraryElementType = Literal["ASSET", "CLASS", "LIBRARY"]
+
+
 class LibraryElement(PropertyGroup):
     name: StringProperty(name="Name")
+    element_type: EnumProperty(items=[(i, i, "") for i in get_args(LibraryElementType)], name="Element Type")
     # Asset group.
     asset_count: IntProperty(name="Asset Count")
     # Asset.
@@ -166,6 +167,7 @@ class LibraryElement(PropertyGroup):
 
     if TYPE_CHECKING:
         name: str
+        element_type: LibraryElementType
         asset_count: int
         ifc_definition_id: int
         is_declared: bool
@@ -217,6 +219,18 @@ class EditedObj(PropertyGroup):
         obj: Union[bpy.types.Object, None]
 
 
+BreadcrumbType = Literal["LIBRARY", "CLASS"]
+
+
+class LibraryBreadcrumb(PropertyGroup):
+    breadcrumb_type: EnumProperty(items=[(i, i, "") for i in get_args(BreadcrumbType)])
+    library_id: IntProperty(description="IFC Definition ID for libraries.")
+
+    if TYPE_CHECKING:
+        breadcrumb_type: BreadcrumbType
+        library_id: int
+
+
 class BIMProjectProperties(PropertyGroup):
     is_editing: BoolProperty(name="Is Editing", default=False)
     is_loading: BoolProperty(name="Is Loading", default=False)
@@ -226,8 +240,7 @@ class BIMProjectProperties(PropertyGroup):
     organisation_name: StringProperty(name="Organisation")
     organisation_email: StringProperty(name="Organisation Email")
     authorisation: StringProperty(name="Authoriser")
-    active_library_element: StringProperty(name="Enable Authoring Mode", default="")
-    library_breadcrumb: CollectionProperty(name="Library Breadcrumb", type=StrProperty)
+    library_breadcrumb: CollectionProperty(name="Library Breadcrumb", type=LibraryBreadcrumb)
     library_elements: CollectionProperty(name="Library Elements", type=LibraryElement)
     active_library_element_index: IntProperty(name="Active Library Element Index")
     filter_mode: bpy.props.EnumProperty(
@@ -321,15 +334,15 @@ class BIMProjectProperties(PropertyGroup):
     library_file: EnumProperty(items=get_library_file, name="Library File", update=update_library_file)
     selected_project_library: EnumProperty(
         items=get_project_libaries,
-        name="Project Library",
-        description="Project library to display elements from",
+        name="Selected Project Library",
+        description="Selected project library to edit or to assign elements to",
         update=update_selected_project_library,
     )
-    filter_by_library: BoolProperty(
-        name="Filter by Library",
-        description="Filter library elements based on selected library. If unselected can be used to assign selected library to library elements.",
+    show_library_tree: BoolProperty(
+        name="Show Library Tree",
+        description="Show project libraries hierarchy or just show the assets classes.",
         default=True,
-        update=filter_by_library_update,
+        update=show_library_tree_update,
     )
     is_editing_project_library: BoolProperty(
         name="Is Editing Project Library",
@@ -357,10 +370,19 @@ class BIMProjectProperties(PropertyGroup):
     def clipping_planes_objs(self) -> list[bpy.types.Object]:
         return list({cp.obj for cp in self.clipping_planes if cp.obj})
 
-    def add_library_asset_group(self, name: str, asset_count: int) -> LibraryElement:
+    def add_library_project_library(self, name: str, asset_count: int, ifc_definition_id: int) -> LibraryElement:
         new = self.library_elements.add()
         new.name = name
         new.asset_count = asset_count
+        new.element_type = "LIBRARY"
+        new.ifc_definition_id = ifc_definition_id
+        return new
+
+    def add_library_asset_class(self, name: str, asset_count: int) -> LibraryElement:
+        new = self.library_elements.add()
+        new.name = name
+        new.asset_count = asset_count
+        new.element_type = "CLASS"
         return new
 
     def get_library_element_index(self, lib_element: LibraryElement) -> int:
@@ -375,8 +397,7 @@ class BIMProjectProperties(PropertyGroup):
         organisation_name: str
         organisation_email: str
         authorisation: str
-        active_library_element: str
-        library_breadcrumb: bpy.types.bpy_prop_collection_idprop[StrProperty]
+        library_breadcrumb: bpy.types.bpy_prop_collection_idprop[LibraryBreadcrumb]
         library_elements: bpy.types.bpy_prop_collection_idprop[LibraryElement]
         active_library_element_index: int
         filter_mode: Literal["NONE", "DECOMPOSITION", "IFC_CLASS", "IFC_TYPE", "WHITELIST", "BLACKLIST"]
@@ -410,8 +431,8 @@ class BIMProjectProperties(PropertyGroup):
         template_file: str
 
         library_file: str
-        selected_project_library: Union[Literal["*", "-"], str]
-        filter_by_library: bool
+        selected_project_library: Union[Literal["-"], str]
+        show_library_tree: bool
         is_editing_project_library: bool
         editing_project_library_id: int
         project_library_attributes: bpy.types.bpy_prop_collection_idprop[Attribute]
@@ -424,6 +445,11 @@ class BIMProjectProperties(PropertyGroup):
         clipping_planes_active: int
         edited_objs: bpy.types.bpy_prop_collection_idprop[EditedObj]
 
+    def get_active_library_breadcrumb(self) -> Union[LibraryBreadcrumb, None]:
+        if self.library_breadcrumb:
+            return self.library_breadcrumb[-1]
+        return None
+
 
 class MeasureToolSettings(PropertyGroup):
     measurement_type_items = [

src/bonsai/bonsai/bim/module/project/ui.py

@@ -392,7 +392,7 @@ class BIM_PT_project_library(Panel):
 
         library_file = IfcStore.library_file
         assert library_file
-        library_is_selected = props.selected_project_library not in ("*", "-")
+        library_is_selected = props.selected_project_library != "-"
 
         row = layout.row(align=True)
         row.prop(self.props, "selected_project_library", text="")
@@ -403,7 +403,7 @@ class BIM_PT_project_library(Panel):
         if library_is_selected and not props.is_editing_project_library:
             row.prop(props, "is_editing_project_library", text="", icon="GREASEPENCIL")
 
-        row.prop(self.props, "filter_by_library", text="", icon="FILTER")
+        row.prop(self.props, "show_library_tree", text="", icon="OUTLINER")
 
         if props.is_editing_project_library:
             row = layout.row(align=True)
@@ -420,8 +420,9 @@ class BIM_PT_project_library(Panel):
             return
 
         row = self.layout.row(align=True)
-        row.label(text=self.props.active_library_element or "Top Level Assets")
-        if self.props.active_library_element:
+        active_library_element = self.props.get_active_library_breadcrumb()
+        row.label(text=(active_library_element.name if active_library_element else "Top Level Assets"))
+        if active_library_element:
             row.operator("bim.rewind_library", icon="FRAME_PREV", text="")
         row.operator("bim.refresh_library", icon="FILE_REFRESH", text="")
         self.layout.template_list(
@@ -511,9 +512,11 @@ class BIM_UL_library(UIList):
     ):
         if item:
             row = layout.row(align=True)
-            if not item.ifc_definition_id:
+            if item.element_type != "ASSET" and item.asset_count > 0:
                 op = row.operator("bim.change_library_element", text="", icon="DISCLOSURE_TRI_RIGHT", emboss=False)
                 op.element_name = item.name
+                op.breadcrumb_type = item.element_type
+                op.library_id = item.ifc_definition_id
             row.label(text=item.name)
             if item.ifc_definition_id and item.is_declarable:
                 if item.is_declared:
@@ -522,7 +525,7 @@ class BIM_UL_library(UIList):
                 else:
                     op = row.operator("bim.assign_library_declaration", text="", icon="KEYFRAME", emboss=False)
                     op.definition = item.ifc_definition_id
-            if item.ifc_definition_id:
+            if item.element_type == "ASSET":
                 if item.is_appended:
                     row.label(text="", icon="CHECKMARK")
                 else:

src/bonsai/bonsai/tool/project.py

@@ -31,6 +31,7 @@ import bonsai.core.unit
 import bonsai.core.owner
 import bonsai.bim.schema
 import bonsai.tool as tool
+from collections import defaultdict
 from bonsai.bim.ifc import IfcStore
 from ifcopenshell.api.project.append_asset import APPENDABLE_ASSET_TYPES
 from pathlib import Path
@@ -39,6 +40,8 @@ from typing import Optional, Union, TYPE_CHECKING, Generator, Callable
 if TYPE_CHECKING:
     from bonsai.bim.module.project.prop import BIMProjectProperties
 
+HiearchyDict = dict[ifcopenshell.entity_instance, "HiearchyDict"]
+
 
 class Project(bonsai.core.tool.Project):
     @classmethod
@@ -296,54 +299,43 @@ class Project(bonsai.core.tool.Project):
                 ifcopenshell.api.document.remove_reference(ifc_file, reference)
 
     @classmethod
-    def get_filter_for_active_library(
+    def get_project_library_elements(
+        cls, project_library: ifcopenshell.entity_instance
+    ) -> set[ifcopenshell.entity_instance]:
+        return set(element for rel in project_library.Declares for element in rel.RelatedDefinitions)
+
+    @classmethod
+    def get_project_library_rels(cls, ifc_file: ifcopenshell.file) -> set[ifcopenshell.entity_instance]:
+        return set(rel for lib in ifc_file.by_type("IfcProjectLibrary") for rel in lib.Declares)
+
+    @classmethod
+    def is_element_assigned_to_project_library(
         cls,
-    ) -> Callable[[list[ifcopenshell.entity_instance]], Generator[ifcopenshell.entity_instance, None, None]]:
-        props = cls.get_project_props()
-        library_file = IfcStore.library_file
-        assert library_file
-
-        selected_project_library = props.selected_project_library if props.filter_by_library else "*"
-
-        if selected_project_library == "*":
-
-            def condition(elements: list[ifcopenshell.entity_instance]):
-                yield from elements
-
-        elif selected_project_library == "-":
-
-            def condition(elements: list[ifcopenshell.entity_instance]):
-                for element in elements:
-                    if not getattr(element, "HasContext", False):
-                        yield element
-
-        else:
-            project_library = library_file.by_id(int(selected_project_library))
-            project_library_rels = set(project_library.Declares)
-            if project_library_rels:
-
-                def condition(elements: list[ifcopenshell.entity_instance]):
-                    for element in elements:
-                        for rel in getattr(element, "HasContext", ()):
-                            if rel in project_library_rels:
-                                yield element
-                                break
-
-            else:
-
-                def condition(elements: list[ifcopenshell.entity_instance]):
-                    # Hacky way to create empty generator.
-                    return
-                    yield
-
-        return condition
+        element: ifcopenshell.entity_instance,
+        project_library_rels: set[ifcopenshell.entity_instance],
+    ) -> bool:
+        if not (has_context := getattr(element, "HasContext", ())):
+            return False
+        return any(rel in project_library_rels for rel in has_context)
 
     @classmethod
     def update_current_library_page(cls):
         props = cls.get_project_props()
-        element_name = props.active_library_element
+        active_library_breadcrumb = props.get_active_library_breadcrumb()
+        change_back = False
+        if active_library_breadcrumb:
+            name = active_library_breadcrumb.name
+            breadcrumb_type = active_library_breadcrumb.breadcrumb_type
+            library_id = active_library_breadcrumb.library_id
+            change_back = True
+
         bpy.ops.bim.rewind_library()
-        bpy.ops.bim.change_library_element(element_name=element_name)
+        if change_back:
+            bpy.ops.bim.change_library_element(
+                element_name=name,
+                breadcrumb_type=breadcrumb_type,
+                library_id=library_id,
+            )
 
     @classmethod
     def get_parent_library(cls, project_library: ifcopenshell.entity_instance) -> ifcopenshell.entity_instance:
@@ -352,3 +344,34 @@ class Project(bonsai.core.tool.Project):
             return nests[0].RelatingObject
         # IfcProject.
         return project_library.HasContext[0].RelatingContext
+
+    @classmethod
+    def get_project_hierarchy(cls, ifc_file: ifcopenshell.file) -> HiearchyDict:
+        """Get project hierarchy in the following form:
+
+        {
+            IfcProject: { IfcProjectLibrary A: { ... }, },
+            IfcProjectLibrary A: { IfcProjectLibrary B: { ... } },
+            IfcProjectLibrary B: { ... },
+        }
+
+        Use IfcProject to get hierarchy root.
+
+        """
+        hierarchy: HiearchyDict = defaultdict(dict)
+        for project_library in ifc_file.by_type("IfcProjectLibrary"):
+            parent_library = cls.get_parent_library(project_library)
+            hierarchy[parent_library][project_library] = hierarchy[project_library]
+        return hierarchy
+
+    @classmethod
+    def load_project_libraries_to_ui(
+        cls, parent_library: ifcopenshell.entity_instance, hierarchy: HiearchyDict
+    ) -> None:
+        libraries = hierarchy[parent_library]
+        props = cls.get_project_props()
+        for project_library in libraries:
+            library_elements = tool.Project.get_project_library_elements(project_library)
+            props.add_library_project_library(
+                project_library.Name or "Unnamed", len(library_elements), project_library.id()
+            )