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Topological Commands

# Topological Commands

Commands change internal structure of the object. They are available from the Command Page of the Form View. Join and Detach commands are also available from "Current Object" menu, other commands can also be found in "Surface" menu. Change Class command is also available from context menu of both 2D Editors

See Programming topological commands topic about performing these operations programmatically.

### Break Command

The Break Command divides a line element in two. To break a line press Break button and click the segment at the point where you would like to break it. This command is a way to add a new internal segment to the line strip in the Cross-section Editor.

### Close Loop Command

The Close Loop command adds a new straight segment which joins ends of the current strip to make it closed. Close Loop command does not have any effect for strips which consist of a single segment. This command is executed only if the resulting loop will have a valid orientation (see Segment Strips) .

### Delete Command

The Delete Command deletes the currently selected segment from the strip. Note that strip in a 2D editor is assumed to be connected at all times, meaning that any two points are linked with a segment strip. Because of that, deleting a middle segment from a non-closed strip will delete the rest of the strip. This will not happen if you are deleting an end segment from a non-closed strip. This command applies only to the selected element in Cross-section view. It does not have any effect for the currently selected object in the Profile View. Delete key from the keyboard is the shortcut for this command.

When a point is selected in Cross-section View the result of this command will be:

• If the strip consists of a single segment, than the resulting object will consist of a single 3D line representing the other edge of the surface patch.
• If the point is an end of a strip which has more than one segment, the surface patch of the adjoined segment will be deleted.
• If the point is an internal point of a strip which has more than one segment, both adjoined patches will be replaced with a single flat patch. This rule has an exception for case when the initial strip is a closed loop with three segments. In the latter case the operation will not be performed because it would lead to an invalid strip.
• If the strip consists of a single point  than the resulting strip will be empty.

### New Knot Command

This command will add a new knot at the current cross-section position if the cross-section position does not coincide with one of existing knots. In the latter case the command does not have any effect. This command is a shortcut for Base > New Knot menu option.

### Change Class Command

Toggles type of  the currently selected line in either of 2D views. Note that Profile View has priority over Cross-Section view with regards of selection.

The Add command will create a new joint in the current strip (strip of patches in case of 3DO or strip of revolved 2D lines in case of SOR) by extending one if its ends. Press the button and click on a point in Cross-section View to insert a new joint. If the strip has more than one end, one of them has to be selected prior to this command. If the strip has at least one joint a new segment connecting the new point will be created. If the strip was empty prior to this command, a single point will be added to the strip.

### Join Command

The Join command attaches the Current Object to another object. Joined sections will move together as a solid object when moved with mouse or by using the Current Object Page. The Join command allows to create complex objects from simpler ones. After issuing the Join command select in 3D View the object you would like to join to. The Model Explorer offers a convenient shortcut for this command.

### Detach Command

The Detach Command detaches currently selected object from the object it is joined to (the parent object). Nothing will happen if the current object does not have a parent. Detach command can also be carried out by menu of the Model Explorer.

### Split Command

The Split Command creates a new object by cutting the current object with the cross-section plane at current cross position.. This command has no effect for Surface Of Revolution type of objects.

### Cut Command

The Cut Command creates a new object by cutting the current object along the currently selected line (Circumference generated by the selected point in case of SOR). If Cross-section editor has no selection no operation is performed.

If surface of the current object is not a closed strip of patches than current object will be split in two along the line. Otherwise a copy of the selected line will be created in the same location and these two lines will be made edges of the current object, which hence will not be closed anymore.

If the selected line is an edge of the current object, a copy of the edge will be created. This line will become a new object in the model.