diff --git a/EGkTriangle3d.h b/EGkTriangle3d.h
index 5e76ded..bdb6829 100644
--- a/EGkTriangle3d.h
+++ b/EGkTriangle3d.h
@@ -1,7 +1,7 @@
 //----------------------------------------------------------------------------
 //  EgalTech 2014-2019
 //----------------------------------------------------------------------------
-// File : EGkTria3d.h           Data : 06.06.19          Versione : 2.1f1
+// File : EGkTria3d.h           Data : 17.12.19          Versione : 2.1l5
 // Contenuto : Dichiarazione classe triangolo Triangle3d.
 //
 //
@@ -10,6 +10,7 @@
 //             07.02.15 DS Agg. GetArea e GetAspectRatio.
 //             15.01.18 LM Agg. flag.
 //             06.06.19 LM Agg. IsPointInsideTriangle.
+//             17.12.19 DS Agg. controllo lunghezza di tutti e tre i lati.
 //
 //----------------------------------------------------------------------------
 
@@ -49,7 +50,9 @@ class Triangle3d
                 return true ;
               }
       bool Validate( bool bOverwrite = false)
-              { if ( AreSamePointApprox( m_ptP[0], m_ptP[1])  ||  AreSamePointApprox( m_ptP[0], m_ptP[2]))
+              { if ( AreSamePointApprox( m_ptP[0], m_ptP[1])  ||
+                     AreSamePointApprox( m_ptP[1], m_ptP[2])  ||
+                     AreSamePointApprox( m_ptP[2], m_ptP[0]))
                    return false ;
                 Vector3d vtV1 = m_ptP[1] - m_ptP[0] ;
                 Vector3d vtV2 = m_ptP[2] - m_ptP[1] ;
@@ -67,7 +70,9 @@ class Triangle3d
                 return AreSameVectorApprox( vtN, m_vtN) ;
               }
       bool IsValid( void) const
-              { if ( AreSamePointApprox( m_ptP[0], m_ptP[1])  ||  AreSamePointApprox( m_ptP[0], m_ptP[2]))
+              { if ( AreSamePointApprox( m_ptP[0], m_ptP[1])  ||
+                     AreSamePointApprox( m_ptP[1], m_ptP[2])  ||
+                     AreSamePointApprox( m_ptP[2], m_ptP[0]))
                    return false ;
                 if ( m_vtN.IsSmall())
                    return false ;