diff --git a/src/NETGENPlugin/NETGENPlugin_NETGEN_2D_ONLY.cxx b/src/NETGENPlugin/NETGENPlugin_NETGEN_2D_ONLY.cxx
index 5fe1108..298c948 100644
--- a/src/NETGENPlugin/NETGENPlugin_NETGEN_2D_ONLY.cxx
+++ b/src/NETGENPlugin/NETGENPlugin_NETGEN_2D_ONLY.cxx
@@ -54,7 +54,9 @@
 namespace nglib {
 #include <nglib.h>
 }
+#ifndef OCCGEOMETRY
 #define OCCGEOMETRY
+#endif
 #include <occgeom.hpp>
 #include <meshing.hpp>
 //#include <meshtype.hpp>
diff --git a/src/NETGENPlugin/NETGENPlugin_NETGEN_3D.cxx b/src/NETGENPlugin/NETGENPlugin_NETGEN_3D.cxx
index e4f5ae7..4ab0a21 100644
--- a/src/NETGENPlugin/NETGENPlugin_NETGEN_3D.cxx
+++ b/src/NETGENPlugin/NETGENPlugin_NETGEN_3D.cxx
@@ -66,7 +66,9 @@
   Netgen include files
 */
 
+#ifndef OCCGEOMETRY
 #define OCCGEOMETRY
+#endif
 #include <occgeom.hpp>
 namespace nglib {
 #include <nglib.h>