Block Format Keyword Describes the surfaces which are inside the box (exclude inner segments).


Only one box_ID is allowed:
(1) (2) (3) (4) (5) (6) (7) (8) (9) (10)
/SURF/BOX/EXT/surf_ID/unit_ID or /SURF/BOX2/EXT/surf_ID/unit_ID


Field Contents SI Unit Example
surf_ID Surface identifier

(Integer, maximum 10 digits)

unit_ID Unit Identifier

(Integer, maximum 10 digits)

surf_title Surface title

(Character, maximum 100 characters)

box_ID Box identifier, which is defined in Boxes

(Integer, maximum 10 digits)



  1. The format is the same as the corresponding options /SURF/type/surf_ID.
  2. Input format for BOX:
    • The external faces are built from all solids (the inner faces are not considered).
    • The segments built from 3-node and 4-node shells are still selected the same way as with /SURF/type/surf_ID and segments from inside of volumic parts (inner segments) will also be excluded.
  3. If type is BOX, all segments supported by solids, shells and 3-node shells with all nodes inside the box or on its external surface are selected (segments lying on solid elements are not considered).
    • If type is BOX2, all segments with at least one node inside the box or on its surface are selected.