diff --git a/EGkTriangle3d.h b/EGkTriangle3d.h
index c4d6d47..c4dba47 100644
--- a/EGkTriangle3d.h
+++ b/EGkTriangle3d.h
@@ -227,6 +227,8 @@ class Triangle3dEx : public Triangle3d
               }
       const TriFlags3d& GetTriFlags( void) const
               { return m_triF ; }
+      void ResetEdgeFlags( void)
+              { m_triF.bFlag[0] = m_triF.bFlag[1] = m_triF.bFlag[2] = true ; }
       bool SetVertexNorm( int nInd, const Vector3d& vtN)
               { if ( nInd < 0  ||  nInd >= 3)
                    return false ;