diff --git a/Polygon_mesh_processing/include/CGAL/Polyhedral_envelope.h b/Polygon_mesh_processing/include/CGAL/Polyhedral_envelope.h
index e43ebd59cc28..0db291e165d7 100644
--- a/Polygon_mesh_processing/include/CGAL/Polyhedral_envelope.h
+++ b/Polygon_mesh_processing/include/CGAL/Polyhedral_envelope.h
@@ -714,7 +714,7 @@ struct Polyhedral_envelope {
   {
     Vector_3 bmin, bmax;
 
-    Orientation ori;
+    Orientation ori = ON_ORIENTED_BOUNDARY; // to avoid maybe uninitialzed warning
 
     for (unsigned int i = 0; i < prismindex.size(); i++){
       if (prismindex[i] == jump){