Using the F2 key to rename all empties with the following names:

Empty near the sphere: firstEmpty

Empty near the "hand": armEmpty

Empty on the right: endEmpty

Our animation will have 120 frames and an FPS of 30. Press the R key,

to apply rotations and bend the arm:

From frame 1 to 30: Rotate the arm close to the "firstEmpty."

From frame 31 to 90: Rotate the arm to the other side, close to

the "endEmpty."

From frame 91 to 120: Rotate the arm away from the "endEmpty."

The animation occurs only in the sphere objects, and to clear your

motion between frames 90 and 120, you can press ALT+R at frame 120.

By pressing the SPACEBAR key, you will see the arm moving in the 3D

Viewport, but the sphere remains in the same location.

Now, select the sphere object and apply three "Copy Location"

constraints. In each constraint, choose as the target object one of the

empties. Change the influence of the constraints with the "endEmpty"

and "armEmpty" to zero (Figure 7.27).