Fix #3001. User can now specify join criteria in drawings. Only elements where all the criteria have the same values are merged.

src/blenderbim/blenderbim/bim/data/pset/EPset_Drawing.ifc

@@ -5,10 +5,10 @@ FILE_NAME('EPset_Drawing.ifc','2020-01-01T00:00:00',(),(),'EPset_Drawing','EPset
 FILE_SCHEMA(('IFC4'));
 ENDSEC;
 DATA;
-#1=IFCPROPERTYSETTEMPLATE('2JhNIvqZrFnAgxfhK0XVQX',$,'EPset_Drawing','',.PSET_OCCURRENCEDRIVEN.,'IfcAnnotation',(#2,#3,#4,#5,#6,#7,#8,#9,#10,#11,#12,#13,#14,#15,#16,#17,#18));
+#1=IFCPROPERTYSETTEMPLATE('2JhNIvqZrFnAgxfhK0XVQX',$,'EPset_Drawing','',.PSET_OCCURRENCEDRIVEN.,'IfcAnnotation',(#2,#3,#4,#5,#6,#7,#8,#9,#10,#11,#12,#13,#14,#15,#16,#17,#18,#19));
 #2=IFCSIMPLEPROPERTYTEMPLATE('23JavTMk98ZxXhrUEnjAcf',$,'TargetView','',.P_SINGLEVALUE.,'IfcLabel',$,$,$,$,$,.READWRITE.);
-#3=IFCSIMPLEPROPERTYTEMPLATE('1yVWUt5H9DAOuu0OaMMLpe',$,'Scale','',.P_SINGLEVALUE.,'IfcLabel',$,$,$,$,$,.READWRITE.);
-#4=IFCSIMPLEPROPERTYTEMPLATE('3gsuPBtU93b8f0gg1pjkq6',$,'HumanScale','',.P_SINGLEVALUE.,'IfcLabel',$,$,$,$,$,.READWRITE.);
+#3=IFCSIMPLEPROPERTYTEMPLATE('1yVWUt5H9DAOuu0OaMMLpe',$,'Scale','The scale of this drawing represented as a numerator and denominator, such as 1/100',.P_SINGLEVALUE.,'IfcLabel',$,$,$,$,$,.READWRITE.);
+#4=IFCSIMPLEPROPERTYTEMPLATE('3gsuPBtU93b8f0gg1pjkq6',$,'HumanScale','The scale of this drawing in human readable format, such as 1:100',.P_SINGLEVALUE.,'IfcLabel',$,$,$,$,$,.READWRITE.);
 #5=IFCSIMPLEPROPERTYTEMPLATE('0AK5C2UpL4$eaac2LszAx$',$,'HasUnderlay','',.P_SINGLEVALUE.,'IfcBoolean',$,$,$,$,$,.READWRITE.);
 #6=IFCSIMPLEPROPERTYTEMPLATE('2j2ZEZR8X5tONm7kli5hM6',$,'HasLinework','',.P_SINGLEVALUE.,'IfcBoolean',$,$,$,$,$,.READWRITE.);
 #7=IFCSIMPLEPROPERTYTEMPLATE('1ttChRysH9UuEX2FeMj5Hu',$,'HasAnnotation','',.P_SINGLEVALUE.,'IfcBoolean',$,$,$,$,$,.READWRITE.);
@@ -23,5 +23,6 @@ DATA;
 #16=IFCSIMPLEPROPERTYTEMPLATE('1$xfo9EVb26QLqmPll2_RK',$,'MetricPrecision','',.P_SINGLEVALUE.,'IfcReal',$,$,$,$,$,.READWRITE.);
 #17=IFCSIMPLEPROPERTYTEMPLATE('38uAtrp9nD_901NO42zd$7',$,'ImperialPrecision','',.P_SINGLEVALUE.,'IfcLabel',$,$,$,$,$,.READWRITE.);
 #18=IFCSIMPLEPROPERTYTEMPLATE('1MX0uffTL6TOvtvEJpxFmk',$,'DecimalPlaces','',.P_SINGLEVALUE.,'IfcInteger',$,$,$,$,$,.READWRITE.);
+#19=IFCSIMPLEPROPERTYTEMPLATE('0joEq0Rd10cxweEh0NeHT6',$,'JoinCriteria','Comma separated selection keys which determine what cut objects are to be joined.',.P_SINGLEVALUE.,'IfcText',$,$,$,$,$,.READWRITE.);
 ENDSEC;
 END-ISO-10303-21;

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

@@ -816,6 +816,13 @@ class CreateDrawing(bpy.types.Operator):
         return classes
 
     def merge_linework_and_add_metadata(self, root):
+        join_criteria = ifcopenshell.util.element.get_pset(self.camera_element, "EPset_Drawing", "JoinCriteria")
+        if join_criteria:
+            join_criteria = join_criteria.split(",")
+        else:
+            # Drawing convention states that same objects classes with the same material are merged when cut.
+            join_criteria = ["class", "material.Name", 'r"Pset.*Common"."Status"']
+
         group = root.findall(".//{http://www.w3.org/2000/svg}g")[0]
         joined_paths = {}
 
@@ -827,11 +834,18 @@ class CreateDrawing(bpy.types.Operator):
 
             el.set("class", " ".join(classes))
 
-            material_name = [c for c in classes if c.split("-")[0] == "material"][0]
+            keys = []
+            for query in join_criteria:
+                key = ifcopenshell.util.selector.get_element_value(element, query)
+                if isinstance(key, (list, tuple)):
+                    keys.extend(key)
+                else:
+                    keys.append(key)
 
-            # Drawing convention states that objects with the same material are merged when cut.
-            if material_name != "material-null" and el.findall("{http://www.w3.org/2000/svg}path"):
-                joined_paths.setdefault(material_name, []).append(el)
+            hash_keys = hash(tuple(keys))
+
+            if el.findall("{http://www.w3.org/2000/svg}path"):
+                joined_paths.setdefault(hash_keys, []).append(el)
 
         for key, els in joined_paths.items():
             polygons = []