The Regions details view is used to create new, and edit existing composite regions. To create a new region, select Composite Region from either the Insert > Regions menu or the shortcut menu available from Mesh in the Outline or Mesh trees. To edit an existing composite region, right-click it in the Outline or Mesh tree view, then select Edit Definition from the shortcut menu.
A composite region is defined by specifying a list of regions and a method for combining them. The Regions details view can be used to create or modify a region by selecting a method of combination from the Combination list and a selection of regions from the Region List.
Note: The Regions details view enables
you to restrict the regions available for selection by limiting them
by Dimension(Filter). Selecting 2D will cause the Region List to only display
2D regions and selecting 3D will cause the Region List to only select 3D regions. Regions of mixed
dimensionality are always available.
A Combination setting of Union combines the area or volume of the selected regions to create a
new region. The new region will include all the regions from which
it is constructed. For example, two or more 3D regions can be combined
to create a new region, which can then be used as the location for
a domain.
A Combination setting of Alias is used to produce a composite region that when resolved is based
upon the same set of primitive regions as the region it is defined
on. A composite region with a Combination of Alias may only reference a single region (this may be
a composite or primitive region). The new composite region may, however,
resolve to more than one primitive region. This feature is useful
to assign recognizable names to regions with non-intuitive names.