Bulk Data Entry Defines boundary connections for an external superelement.
        Format
            
            
                
                            
                                | (1) | 
                                (2) | 
                                (3) | 
                                (4) | 
                                (5) | 
                                (6) | 
                                (7) | 
                                (8) | 
                                (9) | 
                                (10) | 
                            
                        
                            
                                | EXTRN | 
                                GID1 | 
                                C | 
                                GID2 | 
                                C | 
                                GID3 | 
                                C | 
                                GID4 | 
                                C | 
                                  | 
                            
                            
                                |   | 
                                GID5 | 
                                C | 
                                etc | 
                                etc | 
                                  | 
                                  | 
                                  | 
                                  | 
                                  | 
                            
                        
 
             
        
        Example
            
            
                
                            
                                | (1) | 
                                (2) | 
                                (3) | 
                                (4) | 
                                (5) | 
                                (6) | 
                                (7) | 
                                (8) | 
                                (9) | 
                                (10) | 
                            
                        
                            
                                | EXTRN | 
                                1001 | 
                                123 | 
                                1002 | 
                                456 | 
                                1103 | 
                                1234 | 
                                434 | 
                                123456 | 
                                  | 
                            
                            
                                |   | 
                                1340 | 
                                456 | 
                                etc | 
                                etc | 
                                  | 
                                  | 
                                  | 
                                  | 
                                  | 
                            
                        
 
             
        
        Definition
            
            
                
                            
                                | Field | 
                                Contents | 
                                SI Unit Example | 
                            
                        
                            
                                | GIDi | 
                                Identification number of the GRID or SPOINT to which the
                                    external superelement will be connected. No default (Integer >
                                        0)  | 
                                 | 
                            
                            
                                | Ci | 
                                Component numbers. 4
                                        
                                            - GRID
 
                                            - The components refer to the coordinate system
                                                referenced by the grid points.
 
                                            - No default (0 < Integer ≤ 6)
 
                                        
                                        
                                            - SPOINT
 
                                            - Default = blank (blank or 0)
 
                                        
                                      | 
                                 | 
                            
                        
 
             
        
        Comments
            
            
                
                    - EXTRN can only
                        be specified in partitioned Bulk Data sections and is ignored in the main
                        Bulk Data section. 
 
                    - Connection grids must be specified
                        in the partitioned Bulk Data section following BEGIN
                        SUPER = SEID. 
 
                    - Pairs of blank fields may be
                        entered to allow easier modification of the EXTRN entry. 
 
                    - Embedded blanks are not allowed in
                        the fields.