I was having some trouble getting this one set up correctly also but here is how I finally got it to work. It will ask you to scan fighter 1 into the picture front and back, then a fighter 2 front and back. On Fighter 1 scan a large object into the highlighted area on your screen, I chose a shoebox, let it scan front and back, etc. Next on Fighter 2 you want to scan a small object, for example I scanned a water bottle. The reason I scanned a smaller object this time because at the end of the scan for attributes, the damage, health and attack meters seem to be very low compared to when you create a larger object I noticed.
Now onto the fight, do regular punches or body slams with Fighter 1 until Fighter 2's health is close to the end. If this is done correctly and you being (Fighter 1)'s health is close to 100% let the CPU (Fighter 2) hit you a few times so your diamond bar which is on top of the health meter is filled to the max where you see all 4 lines highlighted. When this is done and your meter is filled, your next attack will result with a super move and your achievement should unlock.
Sorry if I had really bad wording in this ach guide but this was the best way I could explain it. If their are any suggestions or comments to make what I wrote above sound a little more easy in any way leave them in the comments below. And definitely please comment if you decide to give this solution a negative vote if at all possible, thanks.