I've been playing with Entities and orientation lately, and I have what I believe is a simple question.
I've modified the Interpolation example to draw the "basis" of the Entity as "long" light red, blue and green lines from the entity's position. As well, I modified it to draw "short" lines along the x, y and z axis. Finally, I've added a button to toggle the orientation property of the entity on and off (the calculated value and undefined).
I've attached an capture of the modified example.  First, I toggle (on, off, on) drawing the reference frame for the Entity's primitive. These match the basis (the "long" lines, that they align with in the demo), but when I toggle the orientation property off (you see the airplane change orientation), they don't match the drawn X, Y and Z vectors (you can see the reference frame no longer aligns).
Is the default orientation for an Entity (Primitive) not the identity rotation? I must be missing something as this is not what I was expecting. Is the orientation not referenced against the ECF frame? Could someone explain to me how this is working?