load clipping planes decorator reopening .blend file

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

@@ -17,7 +17,7 @@
 # along with BlenderBIM Add-on.  If not, see <http://www.gnu.org/licenses/>.
 
 import bpy
-from . import ui, prop, operator, workspace, gizmo
+from . import ui, prop, operator, workspace, gizmo, decorator
 
 classes = (
     operator.AppendEntireLibrary,
@@ -81,6 +81,7 @@ def register():
     if not bpy.app.background:
         bpy.utils.register_tool(workspace.ExploreTool, after={"builtin.transform"}, separator=True, group=False)
     bpy.types.Scene.BIMProjectProperties = bpy.props.PointerProperty(type=prop.BIMProjectProperties)
+    bpy.app.handlers.load_post.append(decorator.toggle_decorations_on_load)
     bpy.types.TOPBAR_MT_file.prepend(ui.file_menu)
     bpy.types.TOPBAR_MT_file_context_menu.prepend(ui.file_menu)
     wm = bpy.context.window_manager
@@ -101,9 +102,10 @@ def register():
 def unregister():
     if not bpy.app.background:
         bpy.utils.unregister_tool(workspace.ExploreTool)
+    del bpy.types.Scene.BIMProjectProperties
+    bpy.app.handlers.load_post.remove(decorator.toggle_decorations_on_load)
     bpy.types.TOPBAR_MT_file.remove(ui.file_menu)
     bpy.types.TOPBAR_MT_file_context_menu.remove(ui.file_menu)
-    del bpy.types.Scene.BIMProjectProperties
 
     wm = bpy.context.window_manager
     kc = wm.keyconfigs.addon

src/blenderbim/blenderbim/bim/module/project/decorator.py

@@ -17,11 +17,26 @@
 # along with BlenderBIM Add-on.  If not, see <http://www.gnu.org/licenses/>.
 
 import gpu
+import bpy
 import bmesh
 import blenderbim.tool as tool
 from bpy.types import SpaceView3D
 from mathutils import Vector
 from gpu_extras.batch import batch_for_shader
+from bpy.app.handlers import persistent
+
+
+@persistent
+def toggle_decorations_on_load(*args):
+    if bpy.context.scene.BIMProjectProperties.clipping_planes:
+        ClippingPlaneDecorator.install(bpy.context)
+    else:
+        ClippingPlaneDecorator.uninstall()
+
+    # NOTE: ProjectDecorator cannot be loaded at reopening .blend file
+    # since selected_vertices and other data is stored in queried object's
+    # custom attributes and they get purged after Blender session is closed
+    # as queried object is linked from separate .blend file.
 
 
 class ProjectDecorator: