Creating Groups Using Boolean Operators

You can create groups using Boolean union, intersection, or difference operators on the entities in existing mesh groups.

This task shows you how to:

See Also
About Groups

Create Union Groups

You can create a group that combines all the entities from two or more existing mesh groups. Mesh groups can be geometric, proximity, spatial, boundary, or manual groups.

  1. From the Group section of the action bar, click Union Group .
    The Union Group dialog box and the Select toolbox appear.
  2. Optional: Enter a Name for the group.
  3. Choose a selection method from the Select toolbox.

    You can select mesh groups or mesh parts from the tree (the default method) or from the Group selection dialog box .

  4. Select mesh groups or mesh parts to add them to the union group.

    The contents of the first mesh group determine the type of the Boolean group. For example, if the first group contains elements, you cannot add a group that contains nodes. If you select mesh parts only, a Boolean group of the type element is created.

    The entities in the selected groups are highlighted.
  5. To make the union group eligible for use with simulation connections, do not select Include connection elements. This works for both groups in the Groups container and groups under a mesh.

    Note: Connections are defined in the Structural Model Creation app.

  6. Click one of the following:
    • OK to save your selections and to close the dialog box. To generate and visualize the group, you must update it.
    • Update to save your selections, close the dialog box, and update the group.
    • Cancel to cancel the modifications and to close the dialog box.
    If you click OK or Update, the group is created and appears in the tree.

Note: When you use mesh groups as supports, the symbol positioning is intended only to indicate support for the feature. The feature symbols might not cover the mesh region as they do for a similar geometry region.

Create Intersection Groups

You can create a group that contains all the entities common to two or more existing mesh groups. Mesh groups can be geometric, proximity, spatial, boundary, or manual groups.

  1. From the Group section of the action bar, click Intersection Group .
    The Intersection Group dialog box and the Select toolbox appear.
  2. Optional: Enter a Name for the group.
  3. Choose a selection method from the Select toolbox.

    You can select mesh groups or mesh parts from the tree (the default method) or from the Group selection dialog box .

  4. Select mesh groups or mesh parts to add them to the intersection group.

    The contents of the first mesh group determine the type of the Boolean group. For example, if the first group contains elements, you cannot add a group that contains nodes. If you select mesh parts only, a Boolean group of the type element is created.

    The entities in the selected groups are highlighted.
  5. To make the intersection group eligible for use with simulation connections, do not select Include connection elements. This works for both groups in the Groups container and groups under a mesh.

    Note: Connections are defined in the Structural Model Creation app.

  6. Click one of the following:
    • OK to save your selections and to close the dialog box. To generate and visualize the group, you must update it.
    • Update to save your selections, close the dialog box, and update the group.
    • Cancel to cancel the modifications and to close the dialog box.
    If you click OK or Update, the group is created and appears in the tree.

Note: When you use mesh groups as supports, the symbol positioning is intended only to indicate support for the feature. The feature symbols might not cover the mesh region as they do for a similar geometry region.

Create Difference Groups

You can create a group by subtracting the entities of one group from those of another.

  1. From the Group section of the action bar, click Difference Group .
    The Difference Group dialog box and the Select toolbox appear.
  2. Optional: Enter a Name for the group.
  3. Choose a selection method from the Select toolbox.

    You can select groups from the tree (the default method) or from the Group selection dialog box .

  4. Select Group A.

    Group A can be a group or mesh part:

    • If you select a group, the contents of the first group determine the type of the Boolean group. For example, if the first group contains elements, you cannot subtract a group that contains nodes.
    • If you select a mesh part, the contents of the second group determine the type of the Boolean group.
    The entities in Group A are highlighted.
  5. Select Group B.

    The entities from Group B will be subtracted from Group A (entities common to both groups will be removed) to create the new group.

    The entities in Group B are highlighted.
  6. To make the group eligible for use with simulation connections, do not select Include connection elements. This works for both groups in the Groups container and groups under a mesh.

    Note: Connections are defined in the Structural Model Creation app.

  7. Click one of the following:
    • OK to save your selections and to close the dialog box. To generate and visualize the group, you must update it.
    • Update to save your selections, close the dialog box, and update the group.
    • Cancel to cancel the modifications and to close the dialog box.
    If you click OK or Update, the group is created and appears in the tree.

Note: When you use mesh groups as supports, the symbol positioning is intended only to indicate support for the feature. The feature symbols might not cover the mesh region as they do for a similar geometry region.