diff --git a/VolZmapGraphics.cpp b/VolZmapGraphics.cpp
index e65235a..8f455ce 100644
--- a/VolZmapGraphics.cpp
+++ b/VolZmapGraphics.cpp
@@ -127,7 +127,7 @@ TestOnNormal( const AppliedVector CompoField[], int nCompoElem)
          dMaxAbsCos = dAbsCurrentCos ;
    }
    // se esiste normale diretta quasi come potenziale edge, allora corner
-   const double CORNER_COS = 0.5 ;
+   const double CORNER_COS = 0.4 ;
    if ( dMaxAbsCos > CORNER_COS) 
       return CORNER ;
    else