diff --git a/LUA_GdbCreateSurf.cpp b/LUA_GdbCreateSurf.cpp
index 6da559e..efa04cd 100644
--- a/LUA_GdbCreateSurf.cpp
+++ b/LUA_GdbCreateSurf.cpp
@@ -805,9 +805,9 @@ LuaCreateSurfTmBySurfBezier( lua_State* L)
    LuaCheckParam( L, 1, nParentId)
    int nBezId ;
    LuaCheckParam( L, 2, nBezId)
-   double dTol ;
+   double dTol = 50 * EPS_SMALL ; // valore di default 
    LuaGetParam( L, 3, dTol) ;
-   double dSideMin ;
+   double dSideMin = 0.1 ; // valore di default
    LuaGetParam( L, 4, dSideMin) ;
 
    LuaClearStack( L) ;