ELTSET (Element Set)

Associate a name with a element set based on various selection criteria and logical operators. Output element sets.

By convention, ifirst,ilast,istride syntax represents a set selection defined either by a set of elements from ifirst to ilast, with increments of istride (1 by default). A set selection can also be defined with eltset,get, eset_name where eset_name has been defined by the following eltset commands. Most commands with the syntax ifirst,ilast,istride can also use eltset,get, elset_name.

SYNTAX

eltset/eset_name/element_attribute_name/ eq OR ne OR lt OR gt OR le OR ge /value/

eltset/eset_name/ union inter not / eset_list/
  
eltset/eset_name/ delete/eset_name/

eltset/eset_name/ inclusive exclusive face /pset,get, pset_name/

eltset/eset_name/ region mregion / region_name OR mregion_name/

eltset/eset_name/ volume/ eq OR ne OR lt OR gt OR le OR ge /value

eltset/eset_name/ aspect/ eq OR ne OR lt OR gt OR le OR ge /value

eltset/eset_name/ list

eltset/eset_name/ write /file_name[.cellset]/ ascii OR binary

eltset/-all- / write /file_name[.cellset]/ ascii OR binary
  
  1. eq equal to, gt greater than, lt less than, ge greater than or equal, le less than or equal to, ne no equal to value of an element attribute
  2. inclusive pset membership - all elements any of whose nodes is in pset
  3. exclusive pset membership - all elements all of whose nodes are in pset
  4. face pset membership - elements if all nodes of a face are in pset
  5. union, inter, not, boolian comparison with other eltsets
  6. region or mregion membership
  7. quality criteria (volume or aspect ratio)
  8. list - list element set members to screen, or list the names of element sets if no ‘eltset_name’ is specified.
  9. write - write element set members to a file
  10. delete - remove element set from mesh object

The mregion and region form of this command calculate the center of mass of the element and determine which mregion or region the center lies in. It is possible if the interface surfaces are curved that the center will not lie in the same mregion or region as the vertices. Using itetclr will give the better result.

EXAMPLES

eltset/element_set1/itetclr/eq/4 

eltset/element_set2/face/pset/get/mypset

eltset/element_set3/inclusive/pset/get/mypset

eltset/element_set4/region/upper 

eltset/element_set5/volume/lt/3.0 

eltset/element_set5/delete

eltset / /list 
cmo / select / mo_hex
intersect_elements / mo_hex / mo_wells / if_inter
eltset / e_refine / if_inter / gt / 0
refine/ eltset / eltset,get,e_refine
cmo / setatt / mo_hex / if_inter / 1,0,0 / 0
eltset / e_refine / delete

These commands will intersect mesh object named mo_hex with mesh object named mo_wells. The attribute if_inter is created by intersect_elements and has a non-zero value for elements intersected by mo_wells. The selected set is refined. It is good practice to clean up if using names and attributes over again. Here we set if_inter values to 0 and remove the element set when we are done.