public Transform setRotation(Quaternion rot) {
        assert Quaternion.isValidQuaternion(rot) : "Invalid rotation " + rot;
        this.rot.set(rot);
        return this;
    }
Sets the rotation component to the argument.

@param rot the desired rotation value (not null, unaffected)
@return the (modified) current instance (for chaining)
jme3-core/src/main/java/com/jme3/math/Transform.java