Refactor qto utils and migrate to bmesh volume calculation. See #1222.

src/ifcblenderexport/blenderbim/bim/module/qto/operator.py

@@ -0,0 +1,51 @@
+import bpy
+import bmesh
+
+
+class CalculateEdgeLengths(bpy.types.Operator):
+    bl_idname = "bim.calculate_edge_lengths"
+    bl_label = "Calculate Edge Lengths"
+
+    def execute(self, context):
+        result = 0
+        for obj in bpy.context.selected_objects:
+            if not obj.data or not obj.data.edges:
+                continue
+            for edge in obj.data.edges:
+                if edge.select:
+                    result += (obj.data.vertices[edge.vertices[1]].co - obj.data.vertices[edge.vertices[0]].co).length
+        bpy.context.scene.BIMQtoProperties.qto_result = str(round(result, 3))
+        return {"FINISHED"}
+
+
+class CalculateFaceAreas(bpy.types.Operator):
+    bl_idname = "bim.calculate_face_areas"
+    bl_label = "Calculate Face Areas"
+
+    def execute(self, context):
+        result = 0
+        for obj in bpy.context.selected_objects:
+            if not obj.data or not obj.data.polygons:
+                continue
+            for polygon in obj.data.polygons:
+                if polygon.select:
+                    result += polygon.area
+        bpy.context.scene.BIMQtoProperties.qto_result = str(round(result, 3))
+        return {"FINISHED"}
+
+
+class CalculateObjectVolumes(bpy.types.Operator):
+    bl_idname = "bim.calculate_object_volumes"
+    bl_label = "Calculate Object Volumes"
+
+    def execute(self, context):
+        result = 0
+        for obj in bpy.context.selected_objects:
+            if not obj.data or not isinstance(obj.data, bpy.types.Mesh):
+                continue
+            bm = bmesh.new()
+            bm.from_mesh(obj.data)
+            result += bm.calc_volume()
+            bm.free()
+        bpy.context.scene.BIMQtoProperties.qto_result = str(round(result, 3))
+        return {"FINISHED"}