From a9e8f2a1c9df7363710aa6213eca608c0bcc71ec Mon Sep 17 00:00:00 2001
From: Christopher Lackner <clackner@cerbsim.com>
Date: Mon, 28 Apr 2025 16:51:55 +0200
Subject: [PATCH] return invalid surfaceindex (index is 0 based)

---
 libsrc/meshing/meshclass.cpp | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/libsrc/meshing/meshclass.cpp b/libsrc/meshing/meshclass.cpp
index d2431c5f..031cd766 100644
--- a/libsrc/meshing/meshclass.cpp
+++ b/libsrc/meshing/meshclass.cpp
@@ -163,7 +163,7 @@ namespace netgen
         if(mesh.PointContainedIn2DElement(p,lami,ii))
           return ii;
       }
-    return 0;
+    return SurfaceElementIndex::INVALID;
   }
 
   SegmentIndex Find1dElement (const Mesh& mesh,