How to get normal x of vector created by two nodes

         *createmarkpanel nodes 1 'Select N1...'
         set n1 [hm_getmark nodes 1]
         hm_markclear nodes 1

            set n1x [ hm_getentityvalue NODES $n1 'globalx' 0 ]
            set n1y [ hm_getentityvalue NODES $n1 'globaly' 0 ]
            set n1z [ hm_getentityvalue NODES $n1 'globalz' 0 ]

   
         *createmarkpanel nodes 1 'Select N2...'
         set n2 [hm_getmark nodes 1]
         hm_markclear nodes 1

            set n2x [ hm_getentityvalue NODES $n2 'globalx' 0 ]
            set n2y [ hm_getentityvalue NODES $n2 'globaly' 0 ]
            set n2z [ hm_getentityvalue NODES $n2 'globalz' 0 ]

      *createmarkpanel nodes 1 'Select N3...'
      set n3 [hm_getmark nodes 1]
      hm_markclear nodes 1

      set vec1x [expr $n2x - $n1x]
      set vec1y [expr $n2y - $n1y]
      set vec1z [expr $n2z - $n1z]

         set n3x [ hm_getentityvalue NODES $n3 'globalx' 0 ]
         set n3y [ hm_getentityvalue NODES $n3 'globaly' 0 ]
         set n3z [ hm_getentityvalue NODES $n3 'globalz' 0 ]

     set vec2x [expr $n3x - $n2x]
     set vec2y [expr $n3y - $n2y]
         set vec2z [expr $n3z - $n2z]

         set vecx [expr $vec1y*$vec2z - $vec1z*$vec2y]
         set vecy [expr $vec1z*$vec2x - $vec1x*$vec2z]
         set vecz [expr $vec1x*$vec2y - $vec1y*$vec2x]
*createmark nodes 1 236
         *createvector 1 $vecx $vecy $vecz
 
*translatemark nodes 1 1 5