------------------------</span>
         <span class="comment">% Get shape function matrix.</span>
         N = shapeFncMtrx(this,Xn)

         <span class="comment">%------------------------------------------------------------------</span>
         <span class="comment">% Get shape function derivatives matrix.</span>
         dNdxi = shapeFncDrv(this,Xn)

         <span class="comment">%------------------------------------------------------------------</span>
         <span class="comment">% Compute jacobi