From dc84d85f7bf7418dc5b27774fa4f9eab8910903b Mon Sep 17 00:00:00 2001
From: Sebastian Friston <sebastian.friston@gmail.com>
Date: Fri, 11 Apr 2025 16:15:08 +0100
Subject: [PATCH] ISSUE #6340 check if material is null before trying to get id

---
 src/serializers/HdfSerializer.cpp | 3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)

diff --git a/src/serializers/HdfSerializer.cpp b/src/serializers/HdfSerializer.cpp
index 50b9be6e62..7dd8c18fc4 100644
--- a/src/serializers/HdfSerializer.cpp
+++ b/src/serializers/HdfSerializer.cpp
@@ -544,7 +544,8 @@ void HdfSerializer::write_style(surface_style_serialization& data, const ifcopen
 	data.name = s.name.c_str();
 	// @todo
 	data.original_name = s.name.c_str();
-	data.id = s.instance->as<IfcUtil::IfcBaseClass>()->id();
+	auto instance = s.instance->as<IfcUtil::IfcBaseClass>();
+	data.id = instance ? instance->id() : 0;
 	if (s.diffuse) {
 		data.diffuse[0] = s.diffuse.ccomponents()(0);
 		data.diffuse[1] = s.diffuse.ccomponents()(1);