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.

The following are the syntax and parameter definitions, click on options in table or scroll down the page.

attribute_name

eltset/eset_name/ attribute_name /eq or ne or lt or gt or le or ge /value/

forms an eltset from elements in attribute_name that compare to value. The comparators are eq equal to, gt greater than, lt less than, ge greater than or equal, le less than or equal to, ne not equal.

delete

eltset/eset_name/ delete

removes a previously define element set from current mesh object

list

eltset/eset_name/ list

eltset / / list

list all elements in eset_name. If the 2nd argument is empty, list all names all of eltsets for the mesh object

logicals

eltset/eset_name/ union inter not / eset_list/

logical operations union, inter and not act on previously defined eltsets. The definition of the unary operator not is extended such that not/e1/e2 means e1 and (not(e2)).

pset

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

forms an eltset from nodes in a pset with name pset_name. The following criteria are used to define which elements node set are included. The selection criteria is required.

• inclusive all elements any of whose nodes is in pset, if a node is on any element, include it. Generally the largest selection.
• exclusive all elements all of whose nodes are in pset, all nodes of an element must be in the set. Generally a smaller selection.
• face elements if all nodes of a face are in pset

region mregion

eltset/eset_name/ region or mregion / region_name /

will return all nodes that are in the specified geometry region or material mregion given by its region_name.

This command calculates 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 material or geometry region as the vertices. Using values of itetclr may give the better result.

volume aspect

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

forms an eltset based on the quality criteria volume or aspect ratio. The value and comparator detirmines the set selection.

write

eltset/eset_name or -all- / write /file_name[.cellset]/ ascii or binary

write or dump an element list with name eset_name to a file, options are ascii or binary. The argument -all- will write all eltsets in the mesh object.

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 

These are various examples of the eltset command.

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

This set of 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.