At our last competition, judges told one of our teams that they could not have anything concave on the front of their robot and had them remove it. The rules that I’ve seen only address concave in terms of possesion. Is this not allowed on the robot for pushing purposes (so long as they only have the one triball)?

First, Judges conduct interviews with teams and review engineering notebooks to determine which teams get judged awards. Referees are the ones who interpret the rules. In particular the Head Referee makes final decisions on legal robots.

I suspect you may have had a volunteer inspector who did not understand the rules - your next step would be to consult with the Head Referee with a Game Manual inland and relevant Q&A answers from GDC.

There is no rules against concave structures. However, the person doing the inspection should point out if a particular mechanism could lead you to possessing more than one tri-ball during a match, and it would be the teams responsibility to avoid finding themselves in such a situation.


Was the concave structure causing the bot to be oversize? An inspector should be measuring your bot, if its oversize you may fail the inspection. They should suggest you make it fit within size and come back to get re-inspected after you do. If its something obvious like an axle shaft sticking out they may suggest cutting it off but what you do to make your bot within size is up to you. In this situation was their concave shape making them to long?

Concave structures even ones with the potential to possess more than one tri-ball should pass inspection. What we are doing in inspections when we see concave structures like that is warning them that if they possess more than one tri-ball during a match that they will be called on it. Just having that shape shouldn’t require a modification to pass inspection.

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Sorry about that, I wasn’t totally clear. It passed inspection and even made it through 2 qualification matches. This was told to them mid-match, and then my team was warned right after that they wouldn’t be able to compete in the next match until it was changed.

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Sounds like they were in possession of more than one tri-ball due to the shape. If warned multiple times or is deemed match affecting this can be a DQ. They can’t be forced to make a change to a concave shape but if in the next match they again possess more than one tri-ball they should expect a DQ.

There is no rule against having a concave shape. The rule is about using a concave shape to possess more than one tri-ball. Next time you have a rule question be prepared to show them the rule if you think they are interpreting it wrong or ask them to show you the rule your violating.


Others will note the Referee can not direct physically altering the robot, only have robot not placed on field if it is not passing inspection rules (such as size constraints)…

At this stage the proper route is to contact the EP and copy your RECF Event Engagement Manager and Team Engagement Manager. The EP and ReCF will figure out how to educate the Head Referee for future events.

As a matter of team integrity, do not call out the specific event. Nothing positive, only negative feeling towards EP/Head Referee… We don’t know if they had to bring in a new referee in for the event unexpectedly (this does happen).


My team had the manual on their phone and our team captain did show the head ref, but she made the final call. It was what it was and they adapted for the next round. I just wanted to see what others thought about it or were seeing something I wasn’t in the 120 page game manual, lol. I appreciate the responses!

I agree totally, which is why I only mentioned the circumstances, and not the event itself. Any number of factors could have been - and probably were - at play. It was more a nuisance than anything else, but they made their arguments and the head ref made the call and that was that. They adapted and moved on to the next match. I just wanted to make sure I wasn’t missing something in the game manual.

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