GROUP_DEF

Manual definition of groups by lists of elements or nodes, materials, or properties or by assigning a previously defined selection.

This page discusses:

ID_NAME

= <id_name_of_group>

Name of the group.

TYPE

= ELEM

= NODE

Type of the group. The entries of the group are element or node identifiers.

FORMAT

= SELECTED

= LIST

= LIST_MAT

= LIST_PROP

= LIST_NODE_ALL

= LIST_NODE_ANY

= LIST_NDGR_ALL

= LIST_NDGR_ANY

= LIST_GROUP

= LIST_SUBTRACT_GROUP

= LIST_ELEM

= LIST_ELGR

= LIST_POINTS

Format, through selection or by explicit specification of a list of elements or nodes (= LIST), a list of materials (= LIST_MAT) or a list of properties (=LIST_PROP) or a list of nodes or node groups where all elements that contain all listed nodes (*_ALL) or one of the listed nodes (*_ANY) are added.

LIST_BEGIN

for FORMAT = LIST*

Beginning of list entries.

<entries of group list>

...

List entries.

Remarks

  1. FORMAT = SELECTED: This group contains all elements (in TYPE=ELEM) and nodes (in TYPE=NODE) that are selected with the command SELECT.
  2. FORMAT = LIST: This group contains all elements (in TYPE=ELEM) or nodes (in TYPE=NODE) which are listed following the parameter LIST_BEGIN.
  3. FORMAT = LIST_MAT: This list contains materials for the selection of elements.
  4. FORMAT = LIST_PROP: This list contains properties for the selection of elements.
  5. FORMAT = LIST_NODE_ALL: This list contains nodes for the selection of elements. All elements that contain only nodes from this list are added to the group.
  6. FORMAT = LIST_NODE_ANY: This list contains nodes for the selection of elements. All elements that contain at least one node from this list are added to the group.
  7. FORMAT = LIST_GROUP: This list contains multiple existing groups (nodes or elements) and creates a new group containing the content of all the previous groups.
  8. FORMAT = LIST_SUBTRACT_GROUP: This list contains the nodes or elements of the first group minus the content of the later groups.
  9. FORMAT = LIST_NDGR_ALL : This list contains node groups for the selection of elements. All elements that contain all nodes from the listed node groups are added to the group.
  10. FORMAT = LIST_NDGR_ANY : This list contains node groups for the selection of elements. All elements that contain at least one of the nodes from the listed node groups are added to the group.
  11. FORMAT = LIST_ELEM: This list contains elements for the selection of nodes. All nodes contained by these elements are added to the node group.
  12. FORMAT = LIST_ELGR: This list contains element groups for the selection of nodes. All nodes contained by these any elements in these groups are added to the node group.
  13. FORMAT = POINTS: The list contains one point in the global Cartesian coordinate system, one each line. For each point, the nearest node to this point will be added to the node group.
  14. Entering LIST_BEGIN is required with FORMAT = LIST* and must be placed at the end of the command. The list with the numbered areas follows this entry. The standard conventions for commentary lines are applicable. The list is closed with END_. The default separate characters for numbered areas are as follows: Thru-Character='-', Increment-Character=':', Separator-Character=','.

Examples


GROUP_DEF
 ID_NAME = my_elem_group
 TYPE    = ELEM
 FORMAT  = LIST
 LIST_BEGIN
 1,5,10-25, 45-60:5
END_

GROUP_DEF
 ID_NAME = "My Group"
 TYPE    = ELEM
 FORMAT  = LIST_MAT
 LIST_BEGIN
 7
END_

Useful for shape optimization:

Selecting all elements for surface identification:


select,elgr,s,elgr,ALL_ELEMENTS
select,elem,s,elgr
SF_IDENT

Select surface nodes:


select,node,s,ND_SF

GROUP_DEF
 ID_NAME = my_surface_node_group
 TYPE    = NODE
 FORMAT  = SELECTED
END_

For combining groups (GroupD = GroupA + GroupB + GroupC):


GROUP_DEF
 ID_NAME = GroupD
 TYPE    = ELEM
 FORMAT  = LIST_GROUP
 LIST_BEGIN
GroupA, GroupB, GroupC
END_

For subtracting groups (GroupD = GroupA - GroupB - GroupC):


GROUP_DEF
 ID_NAME = GroupD
 TYPE    = ELEM
 FORMAT  = LIST_SUBTRACT_GROUP
  LIST_BEGIN
GroupA, GroupB, GroupC
END_