Linked XForm Modifier

The Linked XForm modifier links the transforms for any object or sub-object selection to another object, called the control object. The control object's motion, rotation, and/or scale transforms are passed onto the object or sub-object selection.

Modify panel > Select objects or sub-objects. > Modifier List > Object-Space Modifiers > Linked XForm
Select an object or sub-objects. > Modifiers menu > Animation > Linked XForm

Using Linked XForm

Linked XForm connects any geometry it receives from the stack to another object, which is called the control object. Its single control simply picks the control object. To use this modifier, you must have at least two objects in your scene.

Procedures

To apply a Linked XForm modifier:

Choose a location in an object's stack and apply a Linked XForm from the Modifier List.
On the Parameter's rollout, click Pick Control Object. When animating, do this at frame 0.
Select the object you want to be the control object.
This completes the link. The name of the control object appears on the Parameters rollout.

To apply a Linked XForm modifier at a Sub-Object level:

Select an Editable Mesh or an object to which a Mesh Select modifier has been applied.
Turn on the Vertex sub-object level and select some vertices on the object.
Apply a Linked XForm modifier.
On the Parameter's rollout, click Pick Control Object. When animating, do this at frame 0.
Select another object that you want to control the sub-object selection.
This completes the link. The name of the control object appears on the Parameters rollout.
Move the control object and see how the vertices are affected.

Interface

Control Object: Object that the vertices are linked to. When transformed, the vertices follow.
Pick Control Object: Click this button, and then select the object that you want to be the control object.
Back Transform: Allows an object with a Linked XForm modifier to be linked to a Control Object. Normally, moving the Control Object causes the linked object to move twice as much as it should, once with the Control Object and once with the link. When the switch is turned on, any transforms to the Control Object are only applied to the linked object once. This switch is similar to the 'Back Transform Vertices' switch of the Skin modifier.