In the following procedure, you create a Character Extension to connect the Servo arm to the Mia character so that they can be controlled and keyframed together.

1. In the Scene browser, expand Characters, right-click Mia, and select Create Character Extension from the contextual menu (A).
   

   Scene browser: A. Create Character Extension option

2. Expand the Character Extensions folder in the Scene browser to see the Mia Extension (C).
   

   Scene browser: A. Character Extension added to Mia character B. Character Extensions heading added to the Scene browser C. Character Extension named for the Mia character

3. Switch back to the Producer Perspective view.
4. Alt-drag the ServoControl effector from the Viewer window onto the Mia Extension in the scene browser and select Add to Mia Extension from the contextual menu as shown in the following figure.
   

   A. ServoControl effector B. ServoControl effector added to Mia Extension

   The Servo arm is defined as a Character Extension of Mia, and is considered as a new “body part” of the Mia character.

5. With the ServoControl effector still selected, open the Properties window.
   Note

   The Properties window is a tab in the Resources pane, on the right side of the interface. Or, click Window > Add Property View to show the window.

   

   Asset browser Properties window

6. Select the green custom property Close_Open and drag its slider left and right as shown in the following figure.
   

   A. Servo arm opens B. Custom property Close_Open

   In the Viewer window, the pincer moves on the Servo arm.

7. Alt-drag the Close_Open property over the Mia Extension (A) and select Create 1 Property Reference from the contextual menu (B).
   

   A. Close_Open property dragged to Mia Extension B. Select Create 1 Property Reference

8. Select the Mia Extension in the Scene browser (A), then activate the Lock option in the Properties window (B) so that the Mia Extension properties stay open no matter what you select.
   

   A. Mia Extension selected B. Lock option activated in the Properties window

9. Define Mia’s right shoulder bone as the Reference object for the Character Extension by Alt-dragging the Mia:RightShoulder bone (A) into the Reference Object field in the Properties window (B).
   

   A. Mia:RightShoulder B. Mia:RightShoulder Reference Object

10. Click OK in the Reference Object Change dialog box that appears.

    The Reference object for your Character Extension is used to calculate all future positioning of the Extension, for example when the Character Extension is included in a pose.

    NoteYou can also enable the Add To Full Body option in the Properties window to define whether you want the Character Extension to be keyed when you set keys in Full Body Keying mode.