Here you can edit options of all Xpressionist groups in the project globaly.

Virtual Channels

When this option is checked Xpressionist will change the way animation channels are listed in the Channel Selector. It switches Xpressionist to a mode where all properties that have three values like X, Y, Z or R, G, B will be internally combined to one vector channel. If you check this option, Xpressionist will in example combine the rotation channels of an object which are

Pitch_X
Yaw_Y
Roll_Z

To only one new channel which is

Rotation

This new chnnel is called a "virtual" channel because it is only used internally within Xpressionist but has no corresponding channel with the same name in Animator. This new channel containes the X, Y and Z rotation values of the object. It can be treated like any other vector channel. Components of these channels can be indexed like with any other vector in the project.

If you use this option you will get a unified channel naming that will be consistent regardless of the interpolation settings in Animator. It also makes it easier to use vector operations with properties like scale or rotation.

Read more about vectors here