A feature truly made for this purpose doesn't exist. This is something I always wish Fusion was capable of; some kind of "Probe" you could assign to components in order quantitatively study their absolute or relative movement. Without it current Motion Study is not a study but just "Motion Visualization".
One thing you may do is to define a joint between the two components (perhaps linear, if you want to know distance. Let's call it "measurement joint") and then look at its icon within the 3D model carefully while moving your own joint via Motion Study. Fusion displays the value of joint movement over it, but quite faintly. I have done this once to find out the relationship between two angles in a system. I moved my driving angle in 1 degree increments via Motion Study and recorded the "measurement joint" angle each time.
One note: if the two components are already jointed you can't apply this "measurement joint" directly; you'll need to define a dummy component to apply this joint.
Hamid
