diff --git a/EXE_GdbCreateSurf.cpp b/EXE_GdbCreateSurf.cpp
index ad7468f..595f7ca 100644
--- a/EXE_GdbCreateSurf.cpp
+++ b/EXE_GdbCreateSurf.cpp
@@ -1227,7 +1227,7 @@ ExeCreateSurfTmRuled( int nParentId, int nPtOrCrvId1, int nPtOrCrvId2, int nType
       string sLua = "EgtSurfTmRuled(" + IdToString( nParentId) + "," +
                                         ToString( nPtOrCrvId1) + "," +
                                         ToString( nPtOrCrvId2) + "," +
-                                        ( nType == ISurfTriMesh::RLT_MINDIST ? "MD" : "IP") + "," +
+                                        ( nType == ISurfTriMesh::RLT_MINDIST ? "'MD'" : "'IP'") + "," +
                                         ToString( dLinTol) + ")" +
                     " -- Id=" + ToString( nNewId) ;
       LOG_INFO( GetCmdLogger(), sLua.c_str()) ;