Fix : fill the storey property of an Element with NULL when we don't find any IfcBuildingStorey parent

src/ifcconvert/ColladaSerializer.cpp

@@ -363,8 +363,8 @@ void ColladaSerializer::ColladaExporter::write(const IfcGeom::TriangulationEleme
 		material_references.push_back(material_name);
 	}
 
-	DeferredObject defered = (serializer->settings().get(SerializerSettings::USE_ELEMENT_HIERARCHY) ?
-		DeferredObject(name, representation_id, o->type(), o->transformation().matrix().data(), mesh.verts(), mesh.normals(),
+	DeferredObject defered = (serializer->settings().get(SerializerSettings::USE_ELEMENT_HIERARCHY) && o->storey() != NULL ?
+		DeferredObject(name, representation_id, o->type(), o->transformation().matrix().data(), mesh.verts(), mesh.normals(), 
 			mesh.faces(), mesh.edges(), mesh.material_ids(), mesh.materials(), material_references, mesh.uvs(), *(o->storey())) : 
 		DeferredObject(name, representation_id, o->type(), o->transformation().matrix().data(), mesh.verts(), mesh.normals(),
 				mesh.faces(), mesh.edges(), mesh.material_ids(), mesh.materials(), material_references, mesh.uvs()));

src/ifcconvert/ColladaSerializer.h

@@ -132,12 +132,12 @@ private:
 			
 			if (parent1 == NULL || parent2 == NULL)
 			{
-				bool res = (def_obj1.unique_id < def_obj2.unique_id ? true : false);
+				bool res = (parent1 == NULL) ? true : false;
 				return res;
 			}
 			else
 			{
-				bool res = parent1->name() < parent2->name() ? true : false;
+				bool res = parent1->name().compare(parent2->name()) > 0 ? true : false;
 				return res;
 			}
 		}

src/ifcgeom/IfcGeomIterator.h

@@ -604,6 +604,7 @@ namespace IfcGeom {
 					}
 
 					if (hasParent) { ret->SetFloor(parent_object); }
+					else { ret->SetFloor(NULL); } // Set it so null in order to know that we didn't found any IfcBuildingStorey type parent
 				}
 			}