Basic Group Operations

Geometry Groups

To create or add to a group

  1. On the Command Panel, click on Geometry and then Group.
  2. Click on the Manage Groups action button.
  3. Select Create/Add from the drop-down menu.
  4. Enter in the desired name for the Group Name/ID.
  5. Enter in the appropriate settings.
  6. Click Apply.

The command syntax to create or modify a group is:

Group ["name" | <id>] Add <list of topology entities>

For example, the command,

group "exterior" add surface 1 to 2, curve 3 to 5

will create the group named Exterior consisting of the listed topological entities. Any of the commands that can be applied to the "regular" topological entities can also be applied to groups. For example, mesh Exterior , list Exterior , or draw Exterior .

Elements may specified by name as well. For example, the command

group 'interior' add surface name 'bill' 'john' 'fred'

will add the surfaces named 'bill' 'john' and 'fred' to the group 'interior'. A topological entity can be removed from a group using the command:

Group ["name" | <id>] Remove <entity list>

The Xor operation can also be performed on entities in group. Xor means if an entity is already in the group, the command will delete this entity from the group. If it is not in the group, the entity is then added to the group.

Group ["name" | <id>] Xor <entity list>

The Equals operation assigns the group to be exactly the same as the list given. All other existing members of the group will be removed.

Group ["name" | <id>] Equals <entity list>

Modifying groups by comparing common entities

The Common_To operation looks for geometry entities that are related to the input elements, either as parents or children. For example, specifying all curves common to two surfaces will give all of the curves that are attached to both of the specified surfaces. The elements must be specified by name (specifying by id will not work), and the name must be enclosed in single quotation marks. This option works for all of the group operators given above. The command syntax is:

Group ["name" | <id>] {Add|Equals|Remove|Xor} <entity_type> Common_to <entity_type> Name 'pattern' ['pattern'...]

The following is an example of the common_to operator.

bri x 10
curve 2 name 'joe'
curve 3 name 'alf'
group 'mygroup' add surf common_to curve name 'joe' 'alf'

Mesh Groups

Groups may also contain mesh entities. The commands for adding and removing mesh entities are analogous to those for geometric entities.

To create or add to a mesh group

  1. On the Command Panel, click on Mesh and then Group.
  2. Click on the Manage Groups action button.
  3. Select Create/Add from the drop-down menu.
  4. Enter in the desired name for the Group Name/ID.
  5. Enter in the appropriate settings.
  6. Click Apply.

Group ["name" | <id>] Add {Hex|Face|Edge|Node <id_list>}

Group ["name" | <id>] Remove {Hex|Face|Edge|Node <id_list>}

Group ["name" | <id>] Xor {Hex|Face|Edge|Node <id_list>}

Deleting Groups

To delete a group

  1. On the Command Panel, click on Geometry and then Group.
  2. Click on the Manage Groups action button.
  3. Select Delete/Remove from the drop-down menu.
  4. Select a group to delete.
  5. Select delete and/or any other options from this menu.
  6. Click Apply.

Delete Group <id range> [Propagate]

The option propagate will delete the group specified and all of its contained groups recursively.

Cleaning Out Groups

You can remove all of the entities in a group via the cleanout command:

Group <group_id_range> Cleanout [Geometry|Mesh] [Propagate]

By default all entities will be removed - optionally you can cleanout just geometry or mesh entities. As in delete, the propagate option will cleanout the group specified and all of its contained groups recursively.