From eb1c81514b427511b8ed9c8590407a481b4a4d17 Mon Sep 17 00:00:00 2001
From: Thomas Krijnen <t.krijnen@gmail.com>
Date: Tue, 28 Oct 2025 10:51:31 +0100
Subject: [PATCH] Check for attribute nil #7276 #7291

---
 src/ifcgeom/mapping/mapping.cpp | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/src/ifcgeom/mapping/mapping.cpp b/src/ifcgeom/mapping/mapping.cpp
index 004a41821c..8c130aa5f6 100644
--- a/src/ifcgeom/mapping/mapping.cpp
+++ b/src/ifcgeom/mapping/mapping.cpp
@@ -374,7 +374,7 @@ const IfcUtil::IfcBaseEntity* mapping::get_single_material_association(const Ifc
 #endif
 
 #ifdef SCHEMA_HAS_IfcMaterialConstituentSet
-                if (associated_material->as<IfcSchema::IfcMaterialConstituentSet>()) {
+                if (associated_material->as<IfcSchema::IfcMaterialConstituentSet>() && associated_material->as<IfcSchema::IfcMaterialConstituentSet>()->MaterialConstituents()) {
                     IfcSchema::IfcMaterialConstituentSet* constituentset = associated_material->as<IfcSchema::IfcMaterialConstituentSet>();
                     if (settings_.get<settings::LayersetFirst>().value ? constituentset->MaterialConstituents()->get()->size() >= 1 : constituentset->MaterialConstituents()->get()->size() == 1) {
                         IfcSchema::IfcMaterialConstituent* constituent = (*constituentset->MaterialConstituents()->get()->begin());