> For the complete documentation index, see [llms.txt](https://docs.openbrim.org/llms.txt). Markdown versions of documentation pages are available by appending `.md` to page URLs; this page is available as [Markdown](https://docs.openbrim.org/templates/openbrimfea/geometry-fea/fe-groups-fea.md).

# FE Groups \[FEA]

FE Groups provide a hierarchical organization system for finite elements. They are used to select subsets of elements for load application, result extraction, staged construction states, filtering, and other operations. Groups can be nested using parent-child relationships and can filter elements using expressions.

**Parent Group:** The parent FE group of this group. Establishing parent-child relationships creates a hierarchy of groups. For example, a "Girder\_1" group could be a child of a "Superstructure" group. When a parent group is selected for an operation, all elements in its child groups are included.

**Alignment:** Associates this group with a roadway alignment. When assigned, the group's elements are related to a specific alignment, which is useful for alignment-based coordinate computations and station-dependent operations.

**# of Objects (readonly):** The total number of finite elements that belong to this group. This is automatically computed and includes elements directly assigned to this group and elements in any child groups.


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