All the zombies in the graveyard scene currently walk exactly the same way. To add a little variety, you can create a tweaked walk cycle based on the original walk animation.

To tweak the zombie shuffle

1. Select File > Save Scene As, and save your current work under the name graveyard3.ma.
2. Create a new scene (File > New Scene).
3. Set the Playback End Time box to 200.
   
4. Select File > Create Reference.

   The File Browser appears.

5. Select zombieShuffle.mb and click the Reference button.

   The zombie with its shuffle animation are referenced into the empty scene.

6. Press ‘6’ to view the zombie in shaded mode.
7. Select zombie_shuffle_AST in the Outliner (Window > Outliner).
8. Open the Channel Box / Layer Editor and select the Anim tab in the Layer Editor and make sure the layer named zombieShuffle:Arm_Edits is selected.
9. Open the Attribute Editor and click the zombieShuffle:zombie_shuffle_AST tab. On frame 1 of the animation, set the following attributes:
   • Left Shoulder FK Control Rotate: -8.848, -10.489, 43.284
   • Right Shoulder FK Control Rotate: -13.567, -21.276, -58.994

   The zombies arms rise into a reaching pose.

   
10. In the Attribute Editor, -click the Left Shoulder FK Control Rotate attribute name and select Set Key from the pop-up menu. Do the same for Right Shoulder FK Control Rotate.
11. Repeat steps 8 and 9 at the following frames with the associated values:

    Frame	Attribute	Value
    18	Left Shoulder FK Control Rotate	10.694, -9.344, 61.577
    26	Left Shoulder FK Control Rotate	8.239, 1.676, 65.611
    33	Left Shoulder FK Control Rotate	-8.848, -10.489, 43.2845
    33	Right Shoulder FK Control Rotate	-13.567, -21.276, -58.994

12. Play the scene.

    The zombie shuffles with its arms reaching forward. Since you made the change on an animation layer, the raised arm animation is added on top of the existing animation. For more information on animation layers, see What are animation layers? in the Animation guide.

    

For the first 33 seconds of the animation, the zombies arms behave properly. However, after that its left arm starts fanning out widely. This is because the tweaks you made to the animation layer only affect the first 33 seconds. To fix the rest of the animation, you need to loop your changes so that they span the entire walk cycle.

To loop the tweaks to the zombie’s walk cycle

1. Select the zombieShuffle asset in the Outliner.
2. Select Window > Animation Editors > Graph Editor.
3. Under zombieShuffle:zombie_shuffle_AST > zombieShuffle:Arm_Edits, select Rotate X and then + select the second Rotate Z.

   These entries correspond to the attributes Left Shoulder FK Control Rotate and Right Shoulder FK Control Rotate.

4. Select View > Frame All.
   
5. Marquee select all the curves in the graph.
6. Select Curves > Post Infinity > Cycle.
7. Click an empty spot in the graph to deselect the curves.
8. Select Curves > Bake Channel.

   If you zoom out of the graph, you can now see that all the curves cycle over the first 200 seconds.

9. Close the Graph Editor.

   Now if you play the animation, the zombie’s arms behave properly for the entire walk cycle. If you look at the time slider, you can see that there is now a keyframe on every frame of the animation.