diff --git a/Plugin/LevelsetPlugin.cpp b/Plugin/LevelsetPlugin.cpp
index 4996c3a85de4bf2210e0bf91dc1cd72215b3fdd4..d32b8bb91a54d244d760854314fa3aca68fb858e 100644
--- a/Plugin/LevelsetPlugin.cpp
+++ b/Plugin/LevelsetPlugin.cpp
@@ -1,4 +1,4 @@
-// $Id: LevelsetPlugin.cpp,v 1.17 2001-08-12 10:21:19 geuzaine Exp $
+// $Id: LevelsetPlugin.cpp,v 1.18 2001-08-12 11:02:05 geuzaine Exp $
 
 #include "LevelsetPlugin.h"
 #include "List.h"
@@ -100,6 +100,7 @@ Post_View *GMSH_LevelsetPlugin::execute (Post_View *v)
 	gr[1] = _ref[1]-Yp[0];
 	gr[2] = _ref[2]-Zp[0];
 	prosca(gr,n,&test);
+	test = -test;
 	break;
       default:
 	test = 0.;
diff --git a/benchmarks/3d/Cube-01-ExtrMesh.geo b/benchmarks/3d/Cube-01-ExtrMesh.geo
index c55e7c843dd778459d3e03f340b4bd7cf00cdb78..646c55eefa1e737024b2f6e1e3353dd0888d87a1 100644
--- a/benchmarks/3d/Cube-01-ExtrMesh.geo
+++ b/benchmarks/3d/Cube-01-ExtrMesh.geo
@@ -16,5 +16,6 @@ Extrude Surface {6, {0,0.0,1}}
   //Recombine;
 } ;
 
+Physical Volume(99) = {100,200,300};