Boolean selections — Union Selection (
),
Intersection Selection (
),
Difference Selection (
), and
Complement Selection (
) — are useful to combine two or more selections (union), create a selection of entities that are common to the input selections (intersections), create selection of entities that are in one selection but not in another (difference), and to create a selection as the complement (inverse) of one or more selections (all boundaries except the inflow boundaries, for example). The complement can be convenient if a selection is needed that consists of all boundaries except one or a few. Then it is easier to first create a selection (just the one boundary, for example) and then use a
Complement node to create its complement. All Boolean selection nodes’
Settings windows have similar sections. To add this node, right-click the
Geometry node and choose an option from the
Selections menu.
Based on space dimension, select a Level —
Object,
Domain,
Boundary,
Edge (3D only), or
Point for the selections to add or remove from the
Selections to add (
Selections to intersect,
Selections to subtract, and
Selections to invert) list.
Use the buttons in this section to move, add, or delete selections in the Selections to add (Union),
Selections to intersect (Intersection), or
Selections to invert (Complement) lists. For the
Difference selection node, also choose
Selections to subtract. Click the
Add button (
) to open an
Add dialog box that contains all existing selections for the same geometric entity level. Use the
Move Up (
),
Move Down (
), and
Delete (
) buttons to organize the list.
By default, the Keep selection check box is selected. Clear the check box if you do not want the resulting selection to be available as a named selection in other nodes in the geometry sequence or other parts of the model tree. Doing so can be useful if you let the selection feature contribute to a cumulative selection; see below. If the
Keep selection check box is selected, you can also determine if the selection should appear in applicable settings for physics, materials, and other parts of the model tree outside of the geometry using the
Show in physics list (or
Show in instances if the selection is in a geometry part;
Show in 3D in a plane geometry under a work plane in a 3D component). If the geometric entity level is not set to
Object (any of
Domain,
Boundary,
Edge, or
Point), choose
On (the default) or
Off to show the selection in physics and other settings or not. If the geometric entity level is
Object, choose one of
All levels (that is, all entity levels),
Object selection (in geometry parts only),
Domain selection,
Boundary selection,
Edge selection (3D only),
Point selection, or
Off. For
Show in physics,
All levels is the default; for
Show in instances,
Object selection is the default.
From the Contribute to list, choose an option. In addition to available
Cumulative Selection nodes,
None is always available from the list. To create a new
Cumulative Selection, click
New. Enter a
Name in the
New Cumulative Selection window. Click
OK or press enter. This new cumulative selection is now available from any
Contribute to list for a geometry selection.
