[Figure 17] The two-joint chain with an X, Y, Z rotation order before rotations are applied.

Many animators debate as to what best rotation order should be. Maya, and many other software systems, have their joints default to X as the twisting rotational axis, Y as the secondary rotation, and Z as the primary rotation axis. When creating your characters, you can experiment with changing the rotation order of your joints or objects. In our characters, we like to use the secondary rotation as the second or middle of the order, with the primary rotation being the last. On our joints and on most of our controllers, we decided that we wanted the orientation of the twist and secondary to be affected by the primary rotation. It’s no coincidence that this order is the default rotation order for Maya. We think that this rotation order generally gives us the fewest problems with gimbal lock.

[Figure 18] The two-joint chain with the second joint rotated 75 degrees in Y, causing it to gimbal lock.