# Differences in rules-Herding/Possesion?

So looking thru the rules there are general rules regarding possession but when does herding become possession and are you even aloud to intentionally push multiple balls?

Herding becomes possession when the definition of possession is satisfied.

As for the other part of the question, Q&A was asked this a few days ago and responded:

There is no rule the would prevent simultaneous herding of multiple BALLS, as long as they are not in the POSSESSION of the ROBOT.

but how would you define possession? I know that-

“POSSESSION: Controlling the position and movement of a BALL. A BALL shall be considered in POSSESSION if, as the ROBOT moves or changes orientation (e.g. backs up or spins in place), the BALL remains in approximately the same position relative to the ROBOT.”

but if the balls are free spinning can you still control the general direction of the balls?

If the robot were to suddenly stop, reverse, or spin, would it have to chase a ball that it was pushing before that sudden movement? If the answer is no, the ball is possessed. If the answer is yes, the ball was probably not possessed.

Take a look at 16’s robot from 2008. It had a large frame that came down over the trackballs. If that frame had been bigger, big enough that the trackballs weren’t squeezed, 16 would still have been in possession of a trackball when the frame was around it. If it had had one open side, possession would not necessarily have been the case.

ok. but if your device for holding is a light suction and when you do back up or stop, those balls will have a tendency to follow the robot due to they’re inward, free spinning, rolling motion. then is that considered approximately the same position as the robot? your controlling the direction the balls want to roll, but not truly pulling it with a mechanism.

This is two places where you say the ball “tends to” come along with your robot. It either does or it doesn’t. If it does, that’s possession. If it only sometimes does because your mechanism isn’t 100%, then when it does it is possession. If it doesn’t, it’s not possession.

If you have demonstrated the capability of possessing more than one ball, you will probably be looked at much closer in future matches when you are herding balls. If your mechanism possessed more than one ball before, it’s likely to do it again. So if 2 balls get into your mechanism another time, you’d probably be in trouble, even if possession isn’t demonstrated that time.

Best to reconsider your design now, rather than having to do it on Friday of competition. Remember, referees might not be there to note penalties on practice day.