Flac3D5.0用到結構單元的時候，往往需要鏈接不同結構單元之間同一位置處的節點，這就需要將原有zone-node鏈接刪除，新建立一個node-node鏈接，然后給這個鏈接賦屬性，剛接或可屈服之類。若手動查找每個節點然后鏈接，量大時幾乎是無法完成的，現提供自動鏈接函數。

使用示例：

@install_shell
sel node local xdir=(1,0,0) ydir=(0,1,0) range x 24 24.1
sel node fix lsys range x 24 24.1
sel node fix x yr zr range x 24 24.1
; 開挖西部第一層 z1=40.5,  z2=42.5
@excav(40.5,42.5)
@install_cable_w(1)
@relink(10000)
solve
save quarter_excav_w1

自動鏈接函數：

; Flac3D 5.0
; w.gang.89@foxmail.com
 def relink(begin_link_id)
     dist_tol = 1e-2
     link_id = begin_link_id
     node_num = 0
     node_pnt0 = nd_head
     ; m_pnt = null
     loop while node_pnt0 # null
         ; node_num = node_num + 1
         ; m_pnt1 = get_mem(2)
         ; mem(m_pnt1) = m_pnt
         ; mem(m_pnt1+1) = node_pnt0
         ; m_pnt = m_pnt1
         ; node_pnt0 = nd_next(node_pnt0)
         node_num = node_num + 1
         node_pnt0 = nd_next(node_pnt0)
     endloop

     node_arr = get_array(node_num)
     node_num = 0
     node_pnt0 = nd_head
     loop while node_pnt0 # null
         node_num = node_num + 1
         node_arr(node_num) = node_pnt0
         node_pnt0 = nd_next(node_pnt0)
     endloop

     node_num_minus1 = node_num - 1
     loop ii(1,node_num_minus1)
         node_pnt1 = node_arr(ii)
         node_id1 = nd_id(node_pnt1)
         xxa = nd_pos(node_pnt1,2,1)
         yya = nd_pos(node_pnt1,2,2)
         zza = nd_pos(node_pnt1,2,3)
         ii_plus1 = ii + 1
         loop jj(ii_plus1,node_num)
             node_pnt2 = node_arr(jj)
             node_id2 = nd_id(node_pnt2)
             xxb = nd_pos(node_pnt2,2,1)
             yyb = nd_pos(node_pnt2,2,2)
             zzb = nd_pos(node_pnt2,2,3)
             node_dist = sqrt((xxa-xxb)^2+(yya-yyb)^2+(zza-zzb)^2)
             if node_dist <= dist_tol then
                 link_pnt1 = nd_link(node_pnt1)
                 link_pnt2 = nd_link(node_pnt2)
                 if link_pnt1 = null then
                     link_id = link_id + 1
                     command
                         ; sel set link node_tol=dist_tol
                         sel link id=@link_id @node_id1 target=node tgt_num=@node_id2
                         sel link attach xdir=rigid ydir=rigid zdir=rigid &
                             xrdir=rigid yrdir=rigid zrdir=rigid range id=@link_id
                     endcommand
                 else
                     if link_pnt2 = null then
                         link_id = link_id + 1
                         command
                             ; sel set link node_tol=dist_tol
                             sel link id=@link_id @node_id2 target=node tgt_num=@node_id1
                             sel link attach xdir=rigid ydir=rigid zdir=rigid &
                                 xrdir=rigid yrdir=rigid zrdir=rigid range id=@link_id
                         endcommand
                     else
                         if lk_type(link_pnt1) = lk_type(link_pnt2) then
                         ; value {1,2} denotes node-to-node or node-to-zone link
                             temp = lk_delete(link_pnt2)
                             link_id = link_id + 1
                             command
                                 sel link id=@link_id @node_id2 target = node tgt_num=@node_id1
                                 sel link attach xdir=rigid ydir=rigid zdir=rigid &
                                     xrdir=rigid yrdir=rigid zrdir=rigid range id=@link_id
                             endcommand
                         endif
                     endif
                 endif
             endif
         endloop
     endloop
     temp = lose_array(node_arr)
 end
;  @relink(10000)