Grouping elementsΒΆ

In Mesh module it is possible to create groups of mesh entities: nodes, edges, faces, volumes, 0D elements or balls. One group contains elements of only one type. Groups, unlike sub-meshes, are exported along with mesh entities into the files of following formats: MED, UNV, and CGNS. The group has a color attribute which is used for visualization only and is not exported.

There are three types of groups different by their internal organization:

  1. Standalone group is a static set of mesh entities. Its contents can be explicitly controlled by the user. Upon removal of the entities included into the group, e.g. due to modification of meshing parameter, the group becomes empty and its content can be restored only manually. Hence it is reasonable to create standalone groups when the mesh generation is finished and mesh quality is verified.

    Warning

    Creation and edition of large standalone groups in Creating groups dialog using manual edition is problematic due to poor performance of the dialog.

  2. Group on geometry is associated to a sub-shape or a group of sub-shapes of the main shape and includes mesh entities generated on these geometrical entities. The association to a geometry is established at group construction and cannot be changed. The group contents are always updated automatically, hence the group can be created even before mesh elements generation.

  3. Group on filter encapsulates a About filters, which is used to select mesh entities composing the group from the whole mesh. Criteria of the filter can be changed at any time. The group contents are always updated automatically, hence the group can be created even before mesh elements generation.

The group on geometry and group on filter can be converted to a standalone group.

_images/groups_in_OB.png

“Groups of different types look differently in the Object Browser”

The following ways of group creation are possible:

The created groups can be later:

In the Object Browser, if an item contains more than one child group, it is possible to sort the groups by name in ascending order using Sort children context menu item.

_images/smesh_sort_groups.png

“Sorting groups”

An important tool, providing filters for creation of standalone groups and groups on filter is Selection filter library.