diff --git a/Vector3d.cpp b/Vector3d.cpp
index 2612bed..cb8143f 100644
--- a/Vector3d.cpp
+++ b/Vector3d.cpp
@@ -65,6 +65,26 @@ FromUprightOrtho( const Vector3d& vtV)
    return ( vtV ^ vtAx) ;
 }
 
+//----------------------------------------------------------------------------
+// Definizione dall'ortogonale al primo ricevuto, orizzontale e pił vicino al secondo
+//----------------------------------------------------------------------------
+Vector3d
+FromNearestHorizontalOrtho( const Vector3d& vtV, const Vector3d& vtNear)
+{
+  // se vettore nullo o coincidente con asse Z, imposto asse orizzontale pił vicino a Near
+   if ( vtV.IsZero()  ||  vtV.IsZplus()  ||  vtV.IsZminus()) {
+      Vector3d vtHor( vtNear.x, vtNear.y, 0) ;
+      if ( vtHor.Normalize( EPS_ZERO))
+         return vtHor ;
+      else
+         return X_AX ;
+   }
+  // caso generico
+   Vector3d vtHor = vtV ^ Z_AX ;
+   vtHor.Normalize( EPS_ZERO) ;
+   return ( vtHor * vtNear >= 0 ? vtHor : -vtHor) ;
+}
+
 //----------------------------------------------------------------------------
 // Lunghezza del vettore
 //----------------------------------------------------------------------------