Print unused elements stats / purge unused elements

Added to Purge Data section in Quality Control some tools - https://i.imgur.com/Nz3YoiH.png

1) Print unused elements - useful to investigate how much unused data you have in IFC file.
https://i.imgur.com/9Fkn0JD.png

2) purge unused elements by ifc class, it's doing it in pretty naive way and can be dangerous, so maybe it should be moved to debug section.

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

@@ -38,6 +38,8 @@ classes = (
     operator.SelectHighPolygonMeshes,
     operator.SelectHighestPolygonMeshes,
     operator.ValidateIfcFile,
+    operator.PrintUnusedElementStats,
+    operator.PurgeUnusedElementsByClass,
     prop.BIMDebugProperties,
     ui.BIM_PT_debug,
 )

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

@@ -454,3 +454,44 @@ class OverrideDisplayType(bpy.types.Operator):
         for obj in context.selected_objects:
             obj.display_type = self.display
         return {"FINISHED"}
+
+
+class PrintUnusedElementStats(bpy.types.Operator, tool.Ifc.Operator):
+    bl_idname = "bim.print_unused_elements_stats"
+    bl_label = "Purge Unused Elements Stats"
+    bl_options = {"REGISTER", "UNDO"}
+    bl_description = (
+        "Print all unused elements in current IFC project in system console, not limited to the selected class"
+    )
+
+    ignore_contexts: bpy.props.BoolProperty(name="Ignore Contexts", default=True)
+    ignore_relationships: bpy.props.BoolProperty(name="Ignore Relationships", default=True)
+    ignore_types: bpy.props.BoolProperty(name="Ignore Types", default=True)
+
+    def _execute(self, context):
+        props = context.scene.BIMDebugProperties
+        # ignore some classes that could have zero 0 inverse references by their nature
+        ignore_classes = []
+        if self.ignore_contexts:
+            ignore_classes += ["IfcRepresentationContext"]
+        if self.ignore_relationships:
+            ignore_classes += ["IfcRelationship"]
+        if self.ignore_types:
+            ignore_classes += ["IfcTypeProduct"]
+
+        unused_elements = tool.Debug.print_unused_elements_stats(props.ifc_class_purge, ignore_classes)
+        self.report({"INFO"}, f"{unused_elements} unused elements found, check the system console for the details.")
+
+
+class PurgeUnusedElementsByClass(bpy.types.Operator, tool.Ifc.Operator):
+    bl_idname = "bim.purge_unused_elements_by_class"
+    bl_label = "Purge Unused Elements By Class"
+    bl_description = (
+        "Will find all elements of class that have no inverse refernces and will remove them, use very carefully."
+    )
+    bl_options = {"REGISTER", "UNDO"}
+
+    def _execute(self, context):
+        props = context.scene.BIMDebugProperties
+        purged_elements = core.purge_unused_elements(tool.Ifc, tool.Debug, props.ifc_class_purge)
+        self.report({"INFO"}, f"{purged_elements} unused elements found and removed.")

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

@@ -50,3 +50,4 @@ class BIMDebugProperties(PropertyGroup):
         name="Display Type",
         default="BOUNDS",
     )
+    ifc_class_purge: StringProperty(name="Unused Elements IFC Class", default="")

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

@@ -398,3 +398,10 @@ class BIM_PT_purge(Panel):
         layout.operator("bim.purge_unused_profiles")
         layout.operator("bim.purge_unused_types")
         layout.operator("bim.purge_unused_representations")
+        layout.separator()
+
+        layout.label(text="Purge unused elements by class:")
+        row = layout.row(align=True)
+        row.prop(context.scene.BIMDebugProperties, "ifc_class_purge", text="")
+        row.operator("bim.purge_unused_elements_by_class", text="", icon="TRASH")
+        row.operator("bim.print_unused_elements_stats", text="", icon="INFO")

src/blenderbim/blenderbim/core/debug.py

@@ -23,3 +23,11 @@ def parse_express(debug, filename):
 
 def purge_hdf5_cache(debug):
     debug.purge_hdf5_cache()
+
+
+def purge_unused_elements(ifc, debug, ifc_class):
+    ifc_file = ifc.get()
+    unused_elements = [i for i in ifc_file.by_type(ifc_class) if ifc_file.get_total_inverses(i) == 0]
+    unused_elements_amount = len(unused_elements)
+    debug.remove_unused_elements(unused_elements)
+    return unused_elements_amount

src/blenderbim/blenderbim/tool/debug.py

@@ -20,6 +20,7 @@ import os
 import bpy
 import ifcopenshell.express
 import blenderbim.core.tool
+import blenderbim.tool as tool
 from blenderbim.bim.ifc import IfcStore
 
 
@@ -48,3 +49,42 @@ class Debug(blenderbim.core.tool.Debug):
         obj = bpy.data.objects.new(name, mesh)
         bpy.context.scene.collection.objects.link(obj)
         return obj
+
+    @classmethod
+    def remove_unused_elements(cls, elements):
+        ifc_file = tool.Ifc.get()
+        for element in elements:
+            ifcopenshell.util.element.remove_deep2(ifc_file, element)
+
+    @classmethod
+    def print_unused_elements_stats(cls, requested_ifc_class="", ignore_classes=tuple()):
+        ifc_file = tool.Ifc.get()
+
+        # get list of ifc classes used in model
+        classes = set()
+        requested_ifc_classes = set()
+        for el in ifc_file:
+            if any(el.is_a(i) for i in ignore_classes):
+                continue
+            classes.add(el.is_a())
+            if requested_ifc_class and el.is_a(requested_ifc_class):
+                requested_ifc_classes.add(el.is_a())
+
+        # count unused elements for each class
+        unused = dict()
+        for c in classes:
+            uses = [i for i in ifc_file.by_type(c) if ifc_file.get_total_inverses(i) == 0]
+            if not uses:
+                continue
+            unused[c] = len(uses)
+
+        # print classes and their unsued elements in ascending order
+        if unused:
+            print("Unused elements by classes:")
+            for ifc_class in sorted(unused.keys(), key=lambda x: unused[x]):
+                class_string = ifc_class
+                if ifc_class in requested_ifc_classes:
+                    class_string = "---> " + class_string
+                print(f"{class_string: <50} {unused[ifc_class]: >5}")
+
+        return sum(unused.values())